ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Artikel  (127)
  • 15N  (127)
  • 1995-1999  (63)
  • 1990-1994  (64)
  • 1960-1964
  • 1950-1954
  • Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft  (127)
Sammlung
  • Artikel  (127)
Datenquelle
Schlagwörter
Verlag/Herausgeber
Erscheinungszeitraum
Jahr
Thema
  • 1
    Digitale Medien
    Digitale Medien
    Fate of fertiliser N applied to winter wheat growing on a Vertisol in a Mediterranean environment (1999)
    Springer
    Nutrient cycling in agroecosystems 53 (1999), S. 249-258 
    Details
    ISSN: 1573-0867
    Schlagwort(e): added nitrogen interaction ; fertiliser efficiency ; residual fertiliser nitrogen ; microplots ; 15N ; nitrogen balance ; nitrogen recovery ; split application
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field study using 15N was conducted on a Vertisol in semi-arid Morocco to assess the fate and efficiency of fertiliser N split applied to winter wheat (Triticum aestivum L.). Splitting of fertiliser N is highly crucial in semi-arid regions, considering the increased moisture stress towards the end of the growing season. A N fertilisation rate of 100 kg N ha-1 was split according to two schemes: i) 25% at planting, 50% at tillering and 25% at stem elongation; or ii) 50% at tillering and 50% at stem elongation. The application of 100 kg N ha-1increased the vegetative dry matter production with more than 2000 kg dry matter ha-1 in comparison with the control treatment. Nitrogen fertilisation had no significant effect on the grain yield production. Moreover, the 1000 grain weight decreased from 32 to 26 g due to N fertilisation. Total N uptake was about 50 kg N ha-1 higher for the fertilised plants in comparison with the unfertilised plants, but it was not affected by the splitting pattern of the fertiliser N. Recoveries of 15N-labelled fertiliser by the plant (above-ground plant parts plus roots from the upper 20 cm layer) were low (31% and 24% for the 3-split and 2-split application, respectively). More N in the plant was derived from fertiliser when applied early in the growing season than when applied late in the season. About 13% of the N in the plants was derived from the 50 kg N ha-1 at tillering, while only 5% was derived from the N application (50 kg N ha-1) at stem elongation. At harvest, a high residual of fertiliser-derived N was found in the 0–90 cm profile (62% and 72%, for the 3-split and 2-split application, respectively). Less than 10% of the applied N could not be accounted for, the amount being highest for the application at tillering. This N not accounted for was mainly ascribed to denitrification after an important rainfall event. The application of fertiliser N led to an increase of about 20 kg N ha-1 in soil N uptake by the crop (positive ANI). The results suggested a dominant influence of moisture availability on the fertiliser N uptake by wheat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009780703738
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    The fate of algal nitrogen in a flooded soil system (1999)
    Springer
    Nutrient cycling in agroecosystems 55 (1999), S. 89-94 
    Details
    ISSN: 1573-0867
    Schlagwort(e): algae ; flooded soils ; N cycling ; nitrogen ; 15N ; rice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Algal N labelled with 15N added to a flooded soil in laboratory columns without plants was studied to determine the changes over time in the fate of N assimilated by algae and to study how its fate is affected by (a) exclusion of light simulating complete closure of the rice canopy, and (b) addition of fertilizer-NH4 *. In the light but with no added fertilizer-N there was little net mineralization of the added algal N during the first 4 weeks, but after 8 weeks 42% had been mineralized, of which 95% was denitrified. Exclusion of light caused net mineralization to proceed more rapidly in the first 4 weeks due to the death of algal cells and lowered reassimilation. After 8 weeks 51% had been mineralized, of which 54% was denitrified, 16% volatilized and 30% was present as KCl exchangeable NH4 +-N. Application of fertilizer-NH4 + apparently caused mineralization of 25% of the algal N within one week but the results were probably affected by pool substitution in which labelled N mineralized to NH4 +-N was diluted with fertilizer – NH+ 4 and then immobilized leaving more labelled NH4–N in the mineral pool. After 8 weeks, 42% of algal N had been mineralized, of which 69% was estimated to have been denitrified, 19% lost through NH3 volatilization and 12% remained as extracted NH4 ++NO- 3. Uptake of N by a rice crop would reduce the gaseous losses. Algal N was mineralized quickly enough to be available during the growing season of a rice crop and, depending on field conditions, algae may have a role in assimilating N and protecting it from loss as well as being a major driving force for NH3 volatilization through diurnal increases in pH.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009850915579
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    A comparison of direct and indirect 15N isotope techniques for estimating crop N uptake from organic residues (1999)
    Springer
    Plant and soil 208 (1999), S. 259-270 
    Details
    ISSN: 1573-5036
    Schlagwort(e): crop residues ; isotope dilution ; 15N ; nitrogen ; organic matter ; pool substitution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Experiments were carried out to compare the direct approach for estimating crop N uptake from 15N labelled organic inputs, to two indirect approaches, 15N isotope dilution and A value. In the first experiment soils received 25, 50, 75, or 100 mg N kg soil−1 in the form of Casuarina equisitifolia residues in addition to ammonium sulphate fertiliser, to give a total of 100 mg N kg soil−1 added. This was a cross labelling design, thus two matching sets of treatments, were set up, identical in all but the position of the 15N label. Maize (Zea mays L.) plants were grown in the soils amended with residues for 11 weeks and N derived from residues (Ndfr) estimated using the A-value or the direct approach. The A-value approach appeared to significantly overestimate %Ndfr compared to the direct method. In the second experiment contrasting residues were added to soil, fababean (Vicia faba L. var. minor), alfalfa (Medicago sativa L.), soyabean fixing, (Glycine max (L.) Merrill), soyabean non-fixing, barley (Hordeum vulgare L.) and maize. This was also cross-labelling design, labelled and unlabelled residues were used. Maize plants were grown in these soils for 11 weeks and %Ndfr in the maize plants estimated using 15 N isotope dilution and the direct approach. The 15 N isotope dilution approach also overestimated %Ndfr compared to the direct method in this experiment. Pool substitution appeared to be responsible for the discrepancy between the direct and indirect techniques. It was concluded that 15N isotope dilution and A-value approaches as used in these experiments (i.e where residues and 15N label are added simultaneously) were not appropriate techniques for estimating N derived from organic residues in soils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004529711231
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Microbial transformations of C and N in a boreal forest floor as affected by temperature (1999)
    Springer
    Plant and soil 208 (1999), S. 187-197 
    Details
    ISSN: 1573-5036
    Schlagwort(e): carbon mineralization ; microbial biomass ; 15N ; nitrogen mineralization ; temperature effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of temperature on N mineralization were studied in two organic surface horizons (LF and H) of soil from a boreal forest. The soil was incubated at 5 °C and 15 °C after adding 15 N and gross N fluxes were calculated using a numerical simulation model. The model was calibrated on microbial C and N, basal respiration, and KCl-extractable NH4 +, NO3 −, 15NH4 + and 15 NO3 −. In the LF layer, increased temperature resulted in a faster turnover of all N pools. In both layers net N mineralization did not increase at elevated temperature because both gross NH4 + mineralization and NH4 + immobilization increased. In the H layer, however, both gross NH4 + mineralization and NH4 + immobilization were lower at 15 °C than at 5 °C and the model predicted a decrease in microbial turnover rate at higher temperature although measured microbial activity was higher. The decrease in gross N fluxes in spite of increased microbial activity in the H layer at elevated temperature may have been caused by uptake of organic N. The model predicted a decrease in pool size of labile organic matter and microbial biomass at elevated temperature whereas the amount of refractory organic matter increased. Temperature averaged microbial C/N ratio was 14.7 in the LF layer suggesting a fungi-dominated decomposer community whereas it was 7.3 in the H layer, probably due to predominance of bacteria. Respiration and microbial C were difficult to fit using the model if the microbial C/N ratio was kept constant with time. A separate 15N-enrichment study with the addition of glucose showed that glucose was metabolized faster in the LF than in the H layer. In both layers, decomposition of organic matter appeared to be limited by C availability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004462324452
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Relatively large nitrate efflux can account for the high specific respiratory costs for nitrate transport in slow-growing grass species (1999)
    Springer
    Plant and soil 215 (1999), S. 123-134 
    Details
    ISSN: 1573-5036
    Schlagwort(e): diurnal variation ; 15N ; net nitrate uptake rate ; nitrate efflux ; nitrate influx ; specific respiratory costs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In this paper we address the question why slow-growing grass species appear to take up nitrate with greater respiratory costs than do fast-growing grasses when all plants are grown with free access to nutrients. Specific costs for nitrate transport, expressed as moles of ATP per net mole of nitrate taken up, were 1.5 to 4 times higher in slow-growing grasses than in fast-growing ones (Scheurwater et al., 1998, Plant, Cell & Environ. 21, 995–1005). The net rate of nitrate uptake is determined by two opposing nitrate fluxes across the plasma membrane: influx and efflux. To test whether differences in specific costs for nitrate transport are due to differences in the ratio of nitrate influx to net rate of nitrate uptake, nitrate influx and the net rate of nitrate uptake were measured in the roots of two fast-growing ( Dactylis glomerata L. and Holcus lanatus L.) and two slow-growing (Deschampsia flexuosa L. and Festuca ovina L.) grass species at four points during the diurnal cycle, using 15NO3 -. Efflux was calculated by subtraction of net uptake from influx; it was assumed that efflux of nitrogen represents the flux of nitrate. Transfer of the plants to the solution containing the labelled nitrate did not significantly affect nitrate uptake in the present grass species. The net rate of nitrate uptake was highest during the middle of the light period in all species. Diurnal variation in the net rate of nitrate uptake was mostly due to variation in nitrate influx. Variation in nitrate efflux did not occur in all species, but efflux per net mole of nitrate taken up was higher during darkness than in the light in the slow-growing grasses. The two fast-growing species, however, did not show diurnal variation in the ratio of efflux to net nitrate uptake. Integrated over 24 hours, the slow-growing grasses clearly exhibited higher ratios of influx to net uptake than the fast-growing grass species. Our results indicate that the higher ratio of nitrate influx to net nitrate uptake can account for higher specific costs for nitrate transport in slow-growing grass species compared with those in their fast-growing counterparts, possibly in combination with greater activity of the non-phosphorylating alternative respiratory path. Therefore, under our experimental conditions with plants grown at a non-limiting nitrate supply, nitrate uptake is less efficient (from the point of ATP consumption) in slow-growing grasses than in fast-growing grass species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004559628401
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Nutrient interactions of alley cropped Sorghum bicolor and Acacia saligna in a runoff irrigation system in Northern Kenya (1999)
    Springer
    Plant and soil 210 (1999), S. 249-262 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Acacia saligna ; nutrient competition ; 15N ; resin core ; soil solution ; Sorghum bicolor ; Sr
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In a runoff irrigation system in Northern Kenya, we studied the nutrient interactions of sole cropped and alley cropped Sorghum bicolor (L.) Moench and Acacia saligna (Labill.) H.L. Wendl. The trees were pruned once before the cropping season and the biomass was used as fodder for animals. The nutrient contents in leaf tissue, soil and soil solution were monitored and the uptake of applied tracers (15N, Sr) was followed. The grain yield of alley cropped sorghum was similar to or slightly higher than in monoculture and did not decrease near the tree-crop interface. Foliar N and Ca contents of the crop were higher in the agroforestry combination than in monoculture, corresponding to higher soil N and Ca contents. Soil solution and soil mineral N dynamics indicate an increase of N under the tree row and unused soil N at the topsoil in the alley of the sole cropped trees as well as below 60 cm depth in the crop monoculture. The N use efficiency of the tree+crop combination was higher than the sole cropped trees or crops. Competition was observed for Zn and Mn of both tree and crop whereas for Ca only the tree contents decreased. P, K, Mg and Fe dynamics were not affected by alley cropping at our site. The lower uptake of applied Sr by trees in alley cropping compared to those of the monoculture stand suggested a lower competitiveness of the acacia than sorghum, which did not show lower Sr contents when intercropped. The study showed the usefulness of combining soil and plant analyses together with tracer techniques identifying nutrient competition, nutrient transfer processes and the complementary use of soil nutrients, as the main features of the tree-crop combination.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004698403770
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Monitoring plant physiological characteristics to evaluate mine site revegetation: A case study from the wet-dry tropics of northern Australia (1999)
    Springer
    Plant and soil 215 (1999), S. 73-84 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Acacia ; Eucalyptus ; mine site revegetation ; nitrate ; 15N ; 13C ; tropical savanna ; waste rock dump ; water relations ; tropical woodland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Biologically driven markers or monitors were used to evaluate plant and ecosystem health of uranium-mining affected sites. Plant water, nitrogen (N) and phosphorus (P) status were used to measure physiological characteristics of tree and shrub species at sites perturbed by mining activities (waste rock dumps: WRD 1, WRD 2; mine wastewater irrigated woodland) and of species at undisturbed woodland (tropical savanna). Plant water status was evaluated by measuring leaf relative water content (RWC) and carbon isotope discrimination (δ13C). Leaf RWC varied significantly (P〈0.0001) between wet and dry season in species at the woodland sites with higher RWC in the wet season compared to the dry season. No seasonal differences were observed in RWC in species at the WRDs. Leaf δ13C was similar in species at woodland sites and WRD 2 (−28.8 to −28.1‰) but was significantly (P〈0.05) lower in species at WRD 1 (−27.6‰). This suggests that species at WRD 1 had a lower water availability and/or lower water use compared to species at all other sites. WRD substrate had an up to 4-orders of magnitude greater availability of inorganic phosphate (Pi) compared to woodland soil as determined using in situ ion exchange resin. Pi concentrations in xylem sap of species at WRDs were 2- to 3-fold higher compared to species at woodland sites. Plant nitrate reductase (NR) activity was low in most species at woodland and WRD 1. In contrast, Eucalyptus and Acacia species had high NR activities of up to 300–700 pkat g-1 fw at WRD 2 indicating that these species had greater nitrate use than species at all other sites. Nitrate availability in the top five cm of the profile, as determined using in situ ion exchange resins, increased at all sites in the wet season, but no significant differences were observed between sites using this method. However, traditional soil analysis revealed that WRD substrate had a 2-times higher nitrate content (0 to 1000 mm depth) compared to woodland soil. Thus, it is likely that plants at WRD2 accessed nitrate from deeper parts of the profile. Proline, an indicator of plant stress, was found in appreciable quantities in leaves of herbaceous species but not in woody species. Soil and leaf δ15N were measured to investigate N-cycling and the contribution of diazotrophic N2 fixation to plant N nutrition. Soil δ15N values were highest and most variable at WRD 2 (6.2‰) compared to all other sites (irrigated woodland 3.1‰, undisturbed woodland 2.5‰, WRD 1 0.9‰). This may indicate that N-turnover and nitrification was greatest at WRD 2 leading to greater 15N enrichment of soil N. At all sites, Acacia species were nodulated and putatively fixing N2. With the exception of WRD 2 where leaf δ15N of Acacia species averaged 0.9‰, Acacia species had 15N depleted values characteristic of species that receive N derived from N2 fixation (−0.8 to −0.6‰). Eucalyptus species at the woodland also had 15N depleted values (average −0.4‰) but 15N enriched values (0.3 to 1.8‰) at the three mining affected sites. The results show that for the plants studied foliar δ15N could not be used as an unequivocal measure of plant N sources. The results suggest that biomonitoring of plant and ecosystem health has potential in evaluating performance of mine site revegetation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004721330261
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Relationship between rate of crop growth at date of fertiliser N application and fate of fertiliser N applied to winter wheat (1999)
    Springer
    Plant and soil 214 (1999), S. 49-59 
    Details
    ISSN: 1573-5036
    Schlagwort(e): date of application ; fertiliser ; growth rate ; N uptake efficiency ; 15N ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract To investigate the relationship between the timing of fertiliser N applications and the N use efficiency of wheat, three field experiments with 15N were set up on winter wheat, on three different soils in France. Different crop N demands on the day of fertiliser application were obtained by varying either crop densities or date of fertiliser application. Labelled 15NH4 15NO3 was applied at tillering and during stem elongation. The 15N recovered from plant and soil at different dates after 15N addition and at maturity of wheat was measured. The fate of fertiliser N was rapidly determined, most of the fertiliser N accumulated in the wheat at maturity having been taken up within a few days of application. 15N recovery by the crop at final harvest (%) varied greatly (19–55% N applied) according to crop density, soil type and date of application. It was linearly related to the instantaneous crop growth rate calculated at the day of 15N application. The amount of fertiliser N immobilised in the soil was constant at 20 kg N ha−1, for all soil types and crop densities. Because residual mineral 15N in the soil at harvest was negligible and immobilisation was constant, the level of total 15N measured in the different N pools (soil+plant) reflected the% 15N uptake by the plant. There was consequently a negative linear relationship between the percentage of 15N not recovered for measurement, and crop growth rate (i.e. crop N demand) at date of fertiliser application. These results suggest that crop N demand at the time of N application determines the ability of the crop to compete for N with other processes, and may be a major factor determining the division of N between soil and crop.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004629511235
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Nitrogen transformations in a flooded soil in the presence and absence of rice plants: 2. Denitrification (1998)
    Springer
    Nutrient cycling in agroecosystems 51 (1998), S. 269-279 
    Details
    ISSN: 1573-0867
    Schlagwort(e): denitrification ; gas entrapment ; nitrification inhibitors ; 15N ; rice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Denitrification rates (d) in a flooded alkaline clay were measured following addition of either $$^{15} NO_3^ - or^{15} NH_4^ + $$ to the floodwater, by collecting evolved N2 + N2O in an enclosure in the absence or presence of rice plants. Similar estimates of d were obtained in the $$^{15} NO_3^ - $$ treatment when the isotopic composition of the enclosed atmosphere was determined using arc redistribution or direct mass spectrometric analysis. Approximately 90% of the gaseous products of denitrification were physically trapped in the soil five days after $$^{15} NO_3^ - $$ addition. Mechanical shaking of the soil-water system was an effective method for releasing entrapped gas. Denitrification showed a marked diurnal variation in both $$^{15} NO_3^ - $$ and $$^{15} NH_4^ + $$ treatments planted to rice, with higher rates during the day than at night. Measured rates of denitrification were higher in planted than in unplanted pots for both $$^{15} NO_3^ - $$ and $$^{15} NH_4^ + $$ treatments for normal gas sampling. However, evidence was obtained that this was not a real effect, but was due to release of entrapped gas. Denitrification losses corrected for gas entrapment were estimated at 〈5% of applied $$^{15} NH_4^ + $$ . The 15N mass balance indicated that a much larger amount of applied ammonium (15–25%) was lost by NH3 volatilisation. The rate of denitrification corrected for gas entrapment was similar to the rate of nitrification estimated by inhibition of ammonium oxidation. Although the inhibitors 2-ethynylpyridine and acetylene prevented denitrification by effectively inhibiting nitrification of $$^{15} NH_4^ + $$ , the total recovery of 15N in the soil-plant system did not increase. The total recovery of $$^{15} NH_4^ + $$ was 7–9% higher in the presence than in the absence of rice.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009726524817
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Efficiency of nitrogen fertilizer in the sugarcane-vertical system in Guadeloupe according to growth and ratoon age of the cane (1998)
    Springer
    Nutrient cycling in agroecosystems 52 (1998), S. 9-17 
    Details
    ISSN: 1573-0867
    Schlagwort(e): fertilizer-N ; 15N ; soil N ; sugarcane ; vertisol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Sugarcane is one of the main economic resources of Guadeloupe (France). Cane grown on the island's vertisols shows nitrogen deficiency which is accentuated with each successive ratoon. This deficiency could partially explain the observed decrease in yield. The present study, based on the isotopic N method applied to different ratoons in the field, was aimed at: (i) diagnosing the problem in the crop environment itself; and (ii) quantifying the fertilizer-N balance. The results indicated that decrease in yield and N absorption by the cane was related to ratoon number. The real utilization coefficient for the fertilizer (RUC%) ranged from 6 and 34%, and a high proportion (30–40%) of fertilizer-N was immobilized in the soil (NiS%) after the annual crop cycle. The N absorbed by the cane was essentially derived from the soil. Rainfall at the beginning of (re)growth determined crop development and N supply to the crop. When the water requirements of the crop are satisfied, nitrogen supply and cane yield can be improved in two ways: (i) by increasing the efficiency of the applied N fertilizer (RUC% and NiS%); and (ii) by maintaining the soil's capacity to supply cane with N. This implies maintaining and, if necessary, upgrading the structural state of the vertisols.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009765302105
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 11
    Digitale Medien
    Digitale Medien
    Short-term immobilisation and crop uptake of fertiliser nitrogen applied to winter wheat: effect of date of application in spring (1998)
    Springer
    Plant and soil 206 (1998), S. 137-149 
    Details
    ISSN: 1573-5036
    Schlagwort(e): fertilisation ; microbial immobilisation ; N nutrition ; 15N ; timing ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Previous studies on the fate of fertiliser nitrogen applied to winter wheat in temperate climates have shown that nitrogen (N) applied early, at tillering for wheat, was less efficiently taken up than N applied later in the growth cycle. We examined the extent to which the soil microbial N immobilisation varied during the wheat spring growth cycle and how microbial immobilisation and plant uptake competed for nitrogen. We set up a pulse-15N labelled field experiment in which N was applied at eight development stages from tillering (beginning of March) to anthesis (mid-June). Each application was 50 kg N ha-1 as 15N labelled urea except for the first application which was 25 kg N ha-1. The distribution of fertiliser 15N in shoots, roots, mineral and organic soil N was examined by destructive sampling 7 and 14 days after each 15N pulse. The inorganic 15N pool was almost depleted by day 14. The N uptake efficiency increased with later applications from 45% at tillering to 65% at flowering. N immobilisation was rather constant at 13–16% of N applied, whatever the date of application. The increase in plant 15N uptake resulted in an increase in the total 15N recovery in the plant-soil system (15N in soil +15N in plant), suggesting that gaseous losses were lower at the later application dates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004377006602
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 12
    Digitale Medien
    Digitale Medien
    Nitrogen fixation and nodule occupancy by native strains of Rhizobium on different cultivars of common bean (Phaseolus vulgaris L.) (1998)
    Springer
    Plant and soil 204 (1998), S. 147-154 
    Details
    ISSN: 1573-5036
    Schlagwort(e): common bean ; 15N ; Phaseolus vulgaris ; rhizobial diversity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment under rainfed conditions was conducted in Durango, México, to assess N2-fixation of three cultivars of common bean (Phaseolus vulgaris L.) using 15N-methodology. In addition, diversity of rhizobial isolates obtained from nodules of the different plant genotypes was evaluated by intrinsic antibiotic resistance (IAR), PCR using enterobacterial repetitive intergenic consensus (ERIC) primers, PCR-RFLP analysis of the 16S rRNA gene and multilocus enzyme electrophoresis (MLEE). Selected isolates were used to determine acetylene reduction and competitive ability under greenhouse conditions. The three cultivars tested did not show high variation in N2-fixation, the %Ndfa values ranged from 19 to 26%. Variability in N2-fixation efficiency among various native rhizobial isolates was very high and our results indicate that differences in competitive abilitiy exist also. PCR-RFLP of the 16S rRNA gene and MLEE revealed that most of the isolates belong to the species Rhizobium etli. Intrinsic antibiotic resistance analysis and ERIC-PCR showed high diversity among isolates. In contrast, our results using MLEE show low genetic diversity (H = 0.105).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004399531966
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 13
    Digitale Medien
    Digitale Medien
    Measurement of nitrous oxide and di-nitrogen emissions from agricultural soils (1998)
    Springer
    Nutrient cycling in agroecosystems 52 (1998), S. 131-139 
    Details
    ISSN: 1573-0867
    Schlagwort(e): denitrification ; di-nitrogen ; mass spectrometry ; nitrification ; 15N ; nitrous oxide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nitrous oxide can be produced during nitrification, denitrification, dissimilatory reduction of NO 3 - to NH 4 + and chemo-denitrification. Since soils are a mosaic of aerobic and anaerobic zones, it is likely that multiple processes are contributing simultaneously to N2O production in a soil profile. The N2O produced by all processes may mix to form one pool before being reduced to N2 by denitrification. Reliable methods are needed for measuring the fluxes of N2O and N2 simultaneously from agricultural soils. The C2H2 inhibition and 15N gas-flux methods are suitable for use in undisturbed soils in the field. The main disadvantage of C2H2 is that as well as blocking N2O reductase, it also blocks nitrification and dissimilatory reduction of NO 3 - to NH 4 + . Potentially the 15 N gas-flux method can give reliable measurements of the fluxes of N2O and N2 when all N transformation processes proceed naturally. The analysis of 15N in N2 and N2O is now fully automated by continuous-flow isotope-ratio mass spectrometry for 12-ml gas samples contained in septum-capped vials. Depending on the methodology, the limit of detection ranges from 4 to 11 g N ha-1day-1 for N2 and 4 to 15 g N ha-1day-1 for N2O. By measuring the 15N content and distribution of 15N atoms in the N2O molecules, information can also be obtained to help diagnose the sources of N2O and the processes producing it. Only a limited number of field studies have been done using the 15N gas-flux method on agricultural soils. The measured flux rates and mole fractions of N2O have been highly variable. In rain-fed agricultural soils, soil temperature and water-filled pore space change with the weather and so are difficult to modify. Soil organic C, NO 3 - and pH should be amenable to more control. The effect of organic C depends on the degree of anaerobiosis generated as a result of its metabolism. If conditions for denitrification are not limiting, split applications of organic C will produce more N2O than a single application because of the time lag in the synthesis of N2O reductase. Increasing the NO 3 - concentration above the K m value for NO 3 - reductase, or decreasing soil pH from 7 to 5, will have little effect on denitrification rate but will increase the mole fraction of N2O. The effect of NO 3 - concentration on the mole fraction of N2O is enhanced at low pH. Manipulating the interaction between NO 3 - supply and soil pH offers the best hope for minimising N2O and N2 fluxes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009715807023
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 14
    Digitale Medien
    Digitale Medien
    Nitrogen uptake and use of two contrasting maize hybrids differing in leaf senescence (1998)
    Springer
    Plant and soil 199 (1998), S. 283-291 
    Details
    ISSN: 1573-5036
    Schlagwort(e): dry matter partitioning ; maize ; 15N ; nitrogen uptake ; nitrogen use efficiency ; senescence ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In eastern Canada, the use of fertilizer N has been identified as the most energy-consuming component of maize (Zea mays L.) grain production. As the economic and environmental costs of excessive N fertilization rise, there is an increased emphasis on selection of hybrids with greater N use efficiency (NUE; defined as the ratio of the amount of 15N recovered in grain or stover dry matter to the amount of fertilizer 15N applied to the soil in this study). Using an 15N-labelling approach, a field study was conducted on a tile-drained Brandon loam soil (Typic Endoaquoll) on the Central Experimental Farm at Ottawa, Canada (45°22′ N, 75°43′ W) in 1993 and 1994. Fertilizer N uptake and partitioning within the plant in relation to dry matter changes were monitored during development of a current stay-green maize hybrid and an older early-senescing hybrid grown with three fertilizer N levels (0, 100, 200 kg N ha-1). Dry matter, N concentration and15 N atom% enrichment of plant components were determined at five growth stages. The current stay-green hybrid, ‘Pioneer 3902’ had greater NUE than the old early-senescing hybrid, ‘Pride 5’, which was associated with 24% more dry matter production and 20% more N uptake during grain fill for Pioneer 3902. There was no indication of greater allocation of N to the grain in Pioneer 3902. Our data suggest that prolonged maintenance of green leaf area for photosynthate production during grain fill and the ability to take up available soil N later in grain filling are characteristics of maize hybrids with greater NUE.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004397219723
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 15
    Digitale Medien
    Digitale Medien
    Dual inoculation with strains of Bradyrhizobium japonicum and Azospirillum brasilense to improve growth and biological nitrogen fixation of soybean (Glycine max L.) (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 317-322 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Soybean ; Isotope dilution ; Nitrogen fixation ; Bradyrhizobium japonicum ; Soil sterilization ; 15N ; Azospirillum brasilense ; Bacterial inoculation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of inoculation with Bradyrhizobium japonicum and Azospirillum brasilense strains on the growth of soybean were evaluated with regard to the estimation of N2 fixation using the 15N isotope dilution technique. Inoculation, in general, increased the dry mass of soybean as well as nitrogen content. Dual inoculation with a mixture of B. japonicum and A. brasilense strains was superior over single inoculation with B. japonicum. Nitrogen fixed (Ndfa) varied according to inoculant and soil conditions. Percentages of nitrogen derived from air (% Ndfa) using a non-nodulating isoline were 72% and 76% for B. japonicum and B. japonicum plus A. brasilense, respectively, in non-sterile soil. A similar but higher trend was recorded in sterilized soil, in which the percentages of N2 fixed were 81% and 86% for single and dual inoculation, respectively. The correlation coefficient between N2 fixed and N uptake (r=0.94) and dry mass (r=0.89) was significant. Application of special bacterial inoculants in agricultural systems of Egypt seems to be a promising technology and could be used for improving soybean growth as well as soil fertility, thus minimizing environmental pollution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003740050250
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 16
    Digitale Medien
    Digitale Medien
    Improved diffusion methods for determination of inorganic nitrogen in soil extracts and water (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 413-420 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Ammonium analysis ; 15N ; Nitrate ; Nitrite ; Inorganic N ; Soil extract diffusion method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Diffusion methods previously developed for inorganic-N analysis of soil extracts were modified to improve reliability, increase the dynamic range, extend the scope of applications, and simplify the processing of samples for N-isotope analysis. In these methods, the soil extract is treated with MgO, or MgO plus Devarda‘s alloy, in a 473-ml (1-pint) wide-mouth Mason jar to convert NH4 +-N, NO3 –-N, and/or NO2 –-N to NH3-N. The NH3 thereby liberated is collected in H3BO3-indicator solution in a Petri dish suspended from the Mason-jar lid and determined quantitatively by acidimetric titration. With the modifications described, analyses can be performed on 10- to 100-ml samples of water, 0.5MK2SO4, 1MKCl, 2MKCl, or 4MKCl, at temperatures between 20 and 30°C. Recovery from 10 or 20ml was quantitative in 18–80h with up to 4mgN; recovery from 50 or 100ml was quantitative in 3–13 days with up to 2mgN. Removal of H3BO3 for N-isotope analysis by the Rittenberg process was effected using methanol. Mason-jar diffusion methods are much simpler and more convenient than conventional steam distillations. Comparative studies showed that quantitative determinations are more accurate and precise by diffusion than by distillation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003740050266
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 17
    Digitale Medien
    Digitale Medien
    Nitrogen fertilizers promote denitrification (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 211-220 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Denitrification ; Fertilizer efficiency ; 15N ; Labelled dinitrogen ; Nitrification ; Nitrous oxide ; Urea ; Waterlogged soil ; Water-soluble organic carbon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A laboratory study was conducted to compare the effects of different N fertilizers on emission of N2 and N2O during denitrification of NO3 – in waterlogged soil. Field-moist samples of Drummer silty clay loam soil (fine-silty, mixed, mesic Typic Haplaquoll) were incubated under aerobic conditions for 0, 2, 4, 7, 14, 21, or 42 days with or without addition of unlabelled (NH4)2SO4, urea, NH4H2PO4, (NH4)2HPO4, NH4NO3 (200 or 1000 mg N kg–1 soil), or liquid anhydrous NH3 (1000 mg N kg–1 soil). The incubated soil samples were then treated with 15N-labelled KNO3 (250 mg N kg–1 soil, 73.7 atom% 15N), and incubation was carried out under waterlogged conditions for 5 days, followed by collection of atmospheric samples for 15N analyses to determine labelled N2 and N2O. Compared to samples incubated without addition of unlabelled N, all of the fertilizers promoted denitrification of 15NO3 –. Emission of labelled N2 and N2O decreased in the order: Anhydrous NH3〉urea〈$〉\gg〈$〉 (NH4)2HPO4〉(NH4)2SO4≃NH4NO3≃NH4H2PO4. The highest emissions observed with anhydrous NH3 or urea coincided with the presence of NO2 –, and 15N analyses indicated that these emissions originated from NO2 – rather than NO3 –. Emissions of labelled N2 and N2O were significantly correlated with fertilizer effects on soil pH and water-soluble organic C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003740050233
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 18
    Digitale Medien
    Digitale Medien
    Estimating nitrogen transfer by foliar 15N-labelling in legume – non-legume associations (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 239-242 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Biologically fixed N ; Cereals ; Intercropping ; Foliar labelling ; Grasses ; Legumes ; 15N ; N transfer ; Pastures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We examined the basis for estimating the transfer of legume N to companion cereals or grasses in intercropping or pature systems using the foliar 15N-labelling technique. Published data from three pot experiments were used to illustrate different methods for estimating N transfer. Yield-dependent and yield-independent methods based on measurement of the 15N enrichment of the whole legume biomass at harvest overestimate N transfer. Estimates of N transfer using a yield-independent method based on the 15N enrichment of the legume roots at harvest were inconsistent with estimates based on the isotopic composition of the whole plant. We propose a new mathematical concept for estimating the transfer of legume N based on measurement of the ‘mean pool abundance’ of the legume biomass during the period of N transfer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003740050237
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 19
    Digitale Medien
    Digitale Medien
    Amino acid utilization and isotope discrimination of amino nitrogen in nitrogen metabolism of rat liverin vivo (1997)
    Springer
    European journal of nutrition 36 (1997), S. 340-346 
    Details
    ISSN: 1436-6215
    Schlagwort(e): Protein quality ; endogenous imbalance ; 15N ; natural abundance ; isotope discrimination ; Proteinqualität ; endogene Imbalanz ; 15N ; natürliche Häufigkeit ; Isotopendiskriminierung
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zwischen Harnstoff und Plasmaprotein besteht ein natürlicher Unterschied der15N-Häufigkeit von bis zu 10‰. Die Ursache hierfür ist der verzweigte Stickstoff-Metabolismus in der Leber. Ein Hauptzweig ist die Proteinsynthese, im zweiten Hauptzweig wird der Aminostickstoff zur Harnstoff-Synthese verwendet.15N der Vorläuferaminosäuren wird hierbei, abhängig von den Umsatzraten, im Harnstoff abgereichert und im Protein angereichert. Unter Hinzuziehung der15N-Häufigkeit der Vorläuferaminosäuren, die sich aus Jejunum-Gewebe bestimmen läßt, kann aus der Isotopendiskriminierung in den beiden Stoffwechselzweigen die Utilisierung der Aminosäuren in der Leber berechnet werden. Dies wurde an Ratten nach Fütterung mit verschiedenen Proteinen untersucht. Es zeigte sich, daß bei Verzehr von hochwertigen Proteinen die Utilisierung der Aminosäuren im Stoffwechsel der Leber bei bedarfsgerechter Fütterung besser war (Molkenprotein: 〉85%) als bei Proteinkarenz (70%). Das bedeutet, daß das Muster der aus dem metabolischen Pool verfügbaren Aminosäuren bei Proteinkarenz eine Imbalanz aufweist. Durch exogene Aminosäuren aus der Nahrung kann diese endogene Imbalanz offenbar komplementierend ausgeglichen werden, so daß die Stickstoffausscheidung bei nicht bedarfsüberschreitendem Verzehr sogar unter den Werten der sogenannten „obligaten“ oxidativen Verluste liegen kann. Die Qualität von Nahrungsproteinen spiegelt sich also nicht nur in den N-Bilanzen wider. Sie wird auch durch Bestimmung der Utilisierung der Aminosäuren im Stoffwechsel der Leber mit Hilfe der Analyse der Isotopendiskriminierung quantifizierbar. Zusätzlich wird mit dieser Methode eine Aussage über die Qualität des Musters der metabolisch verfügbaren Aminosäuren gewonnen.
    Notizen: Summary Urea and plasma protein differ in natural15N abundance up to 10‰ The origin of this difference is the branched nitrogen metabolism in the liver. One main branch is the protein synthesis pathway, the other the urea synthesis pathway. By this branching15N of precursor amino acids is depleted in urea while it is enriched in protein. With the15N abundance of precursor amino acids, which may be taken from jejunum tissue, utilization of amino acids in liver metabolism can be calculated from isotope discrimination in either pathway. This was investigated by feeding different proteins to rats. When feeding high quality protein (whey protein) utilization of amino acids in liver metabolism at requirement intake was better than at zero protein intake (〉85% vs. 70%). From this we conclude that the pattern of amino acids available from the metabolic pool at zero protein intake is characterized by an imbalance. This endogenous imbalance can be complemented by exogenous dietary amino acids so that nitrogen excretion may even be smaller than the so-called „obligatory“ losses of intakes not exceeding requirement. Thus, the quality of dietary protein is reflected not only by N balance. It also may be quantified by analysis of isotope discrimination in nitrogen metabolism of the liver. In addition, the quality of amino acid pattern available from the metabolic pool is indicated by this method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01617819
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 20
    Digitale Medien
    Digitale Medien
    Detection and characterization of nitrogen circulation through the sieve tubes and xylem vessels of rice plants (1997)
    Springer
    Plant and soil 196 (1997), S. 233-237 
    Details
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; 13N ; 15N ; phloem sap ; positron-emitting tracer imaging system ; rice ; xylem
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nitrogen movement through the xylem vessels and sieve tubes in rice plants was studied using xylem and phloem sap analysis in combination with stable and radioactive nitrogen isotope techniques. More than 90% of nitrogen was translocated in the sieve tubes of rice plants as amino acids. When 15N (99.6 atom%) was applied as a nitrate to the root, 15N first appeared in phloem sap of the leaf sheath within 10 minutes and increased to 37 atom% excess 5 hours after the experiment had started. In long-term experiments, 63% of nitrogen in the phloem sap of the leaf sheath and 15% in that of the uppermost internode came from nitrogen absorbed within the last 24 hours and 50 hours, respectively. To obtain information about the more rapid circulation of nitrogen in the plant, radioactive 13N was used as a tracer. A positron-emitting tracer imaging system was used to show that 13N was transferred to the leaf sheath within 8 minutes of its application to the roots. Analysis of the xylem sap of the leaf sheath showed that when the nitrate was applied to the roots, most of the nitrogen in the xylem was transported as a nitrate. These data showed that phloem and xylem sap analysis together with the stable and radioactive nitrogen techniques provide a good method for the detection of nitrogen cycles in plants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004254124898
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 21
    Digitale Medien
    Digitale Medien
    Turnover of residual 15N-labelled fertilizer N in soil following harvest of oilseed rape (t Brassica napus L.) (1997)
    Springer
    Plant and soil 190 (1997), S. 193-202 
    Details
    ISSN: 1573-5036
    Schlagwort(e): extractable organic N ; fertilizer N ; mineral N ; 15N ; N loss ; oilseed rape ; soil microbial biomass N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We studied the fate of 15N-labelled fertilizer nitrogen in a sandy loam soil after harvest of winter oilseed rape (Brassica napus L. cv. Ceres) given 100 or 200 kg N ha-1 in spring, with or without irrigation. Our main objective was to quantify the temporal variations of the soil mineral N, the extractable soil organic N and soil microbial biomass N, and fertilizer derived N in these pools during autumn and winter. Nitrogen use efficiency of the oilseed rape crop varied from 47% of applied N in the 100N, irrigated treatment to 34% in the 200N, non-irrigated treatment. However, only in the latter treatment did we find significantly higher fertilizer derived soil mineral N than in the three other treatments which all had low soil mineral N contents at the first sampling after harvest (8 days after stubble tillage). Between 31% and 42% of the applied N could not be accounted for in the harvested plants or 0-15 cm soil layer at this first sampling. Over the following autumn and winter none of the remaining fertilizer derived soil N was lost from the 0–5 cm depth, but from the 5–15 cm depth a marked proportion of N derived from fertilizer was lost, probably by leaching. Negligible amounts of fertilizer derived extractable soil organic and mineral N (〈1 kg N ha-1, 0-15 cm) were found in all treatments after the first sampling. Soil microbial biomass N was not significantly affected by treatments and showed only small temporal variability (±11% of the mean 76 kg N ha-1, 0- 15 cm depth). Surprisingly, the average amount of soil microbial biomass N derived from fertilizer was significantly affected by the treatments, with the extremes being 5.5 and 3.1 kg N ha-1 in the 200N, non-irrigated and 100N, irrigated treatments, respectively. Also, the estimated exponential decay rate of microbial biomass N derived from fertilizer, differed greatly (2 fold) between these two treatments, indicating highly different microbial turnover rates in spite of the similar total microbial biomass N values. In studies utilising 15N labelling to estimate turnover rates of different soil organic matter pools this finding is of great importance, because it may question the assumption that turnover rates are not affected by the insertion of the label.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004253611044
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 22
    Digitale Medien
    Digitale Medien
    Varietal differences in perennial ryegrass for nitrogen use efficiency in leaf growth following defoliation: performance in flowing solution culture and its relationship to yield under simulated grazing in the field (1997)
    Springer
    Euphytica 98 (1997), S. 109-119 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Lolium perenne ; nitrate uptake ; nitrogen remobilization ; 15N ; regrowth ; nitrogen-use efficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Varietal differences in rates of NO3 uptake and remobilization of nitrogen (N) during a cycle of severe defoliation and regrowth were assessed in perennial ryegrass (Lolium perenne L.) varieties Ba11778, Aberelan, Talbot and Gator. Plants were grown in flowing solution culture for 34 days, prior to a 30 d treatment period, including 21 d of regrowth. Net uptake of NO3 was measured continuously from solutions maintained automatically at 10 mmol m-3NO3.15 N-labelled NO3 3 was supplied to the plants in situ for either 21 h immediately prior to defoliation, or for 7-11 days afterwards, to measure remobilization of N from roots and stubble into the regrowing leaves. The four varieties differed only slightly in total dry matter production over 30 d, but varied substantially in post-defoliation specific growth rate by the leaf fraction. Gator was the lowest ( 0.11 g g-1 d-1), Ba11778 the highest ( 0.15 g g-1 d-1) and Aberelan and Talbot intermediate in leaf regrowth rate. Varieties did not vary significantly in shoot: root dry weight ratio, but the rate of NO3 uptake per unit of leaf fresh weight during regrowth was 27% lower in Ba11778 than in Gator. Leaves of Ba11778 and Aberelan had a lower organic N concentration in the dry matter at the end of the regrowth period than Talbot, which, in turn, had a lower concentration than Gator. Varieties differed in amount of leaf dry matter produced per unit of N absorbed by the plants after defoliation, the values (g g-1 N) being Ba11778 (22.6 ), Aberelan (20.7), Talbot (18.3) and Gator (16.7). More N was remobilized from the roots than from the stubble after defoliation. There were no significant differences among varieties in the amount and rate of N remobilization following defoliation. In earlier field experiments employing frequent cutting to simulate grazing, Ba11778 and Aberelan yielded at least 10% more dry matter annually than Talbot which, in turn, outyielded the amenity variety Gator by a similar amount. Thus the present results are consistent with the hypothesis that the efficiency of N use in leaf growth is an important factor determining genetic variation in productivity under frequent defoliation in the field when the herbage produced consists primarily of leaf.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003080007976
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 23
    Digitale Medien
    Digitale Medien
    Crop uptake and leaching of 15N applied in ruminant slurry with selectively labelled faeces and urine fractions (1997)
    Springer
    Plant and soil 197 (1997), S. 233-239 
    Details
    ISSN: 1573-5036
    Schlagwort(e): mineral fertilizer ; 15N ; nitrate leaching ; slurry ; spring barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two animal slurries either labelled with 15N in the urine or in the faeces fraction, were produced by feeding a sheep with unlabelled and 15N-labelled hay and collecting faeces and urine separately. The slurries were applied (12 g total N -2) to a coarse sand and a sandy loam soil confined in lysimeters and growing spring barley (Hordeum vulgare L). Reference lysimeters without slurry were supplied with15 NH4 15NO3 corresponding to the inorganic N applied with the slurries (6 g N m-2). In the second year, all lysimeters received unlabelled mineral fertilizer (6 g N m-2) and grew spring barley. N harvested in the two crops (grain + straw) and the loss of nitrate by leaching were determined. 15N in the urine fraction was less available for crop uptake than mineral fertilizer 15N. The first barley crop on the sandy loam removed 49% of the 15N applied in mineral fertilizer and 36% of that applied with urine. The availability of fertilizer 15N (36%) and urine15 N (32%) differed less on the coarse sand. Of the15 N added with the faeces fraction, 12–14% was taken up by the barley crop on the two soils. N mineralized from faeces compensated for the reduced availability of urine N providing a similar or higher crop N uptake in manured lysimeters compared with mineral fertilized ones. About half of the total N uptake in the first crop originated from the N applied either as slurry or mineral fertilizer. The remaining N was derived from the soil N pool. Substantially smaller but similar proportions of15 N from faeces, urine and fertilizer were found in the second crop. The similar recoveries indicated a slow mineralization rate of the residual faeces N since more faeces was left in the soil after the first crop. More N was lost by leaching from manured lysimeters but as a percentage of N applied, losses were similar to those from mineral fertilizer. During the first and second winter, 3–5% and 1–3%, respectively, of the 15N in slurry and mineral fertilizer was leached as nitrate. Thus slurry N applied in spring just before sowing did not appear to be more prone to loss by nitrate leaching than N given in mineral fertilizer. Slurry N accounted for a higher proportion of the N leached, however, because more N was added in this treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004224615075
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 24
    Digitale Medien
    Digitale Medien
    Volatilization losses of surface-applied urea nitrogen from Vertisols in the Indian semi-arid tropics (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 345-349 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Vertisol ; pH ; Cation exchange capacity ; Moisture ; Urea ; 15N ; Nitrogen losses ; Ammonia volatilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The N loss from Vertisols was estimated by measuring the loss of 15N-labelled urea N under conditions that promote NH3 volatilization. Urea granules were placed on the top of 150-mm deep soil columns (Vertisols) collected from three sites with a range in pH, electrical conductivity, and cation exchange capacity. There were two contrasting moisture treatments, one near field capacity (wet) and another with intermittent wetting of the soil surface before allowing the columns to dry (moist-dry). The results indicated that losses were influenced markedly by pH and moisture treatment, being 29.5, 33.5, and 33% from the wet soils and 37, 42, and 40.5% from the moistdry soils with pH values of 7.7, 8.2, and 9.3, respectively. These observations clearly indicate that broadcasting of urea on the surface of Vertisols may cause substantial N losses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00334581
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 25
    Digitale Medien
    Digitale Medien
    Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 93-98 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Added nitrogen interaction ; Alkaline-hydrolysing fertilizer ; Aqua ammonia ; Gross N immobilization ; Gross N mineralization ; 15N ; Soluble organic N availability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Organic N solubilized by NH3(aq) was extracted from 15N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, gross N immobilization, and nitrification in soils with or without addition of unlabelled soluble organic N were estimated by models based on the dilution of the NH 4 + or NO inf3 sup- pools, which were labelled with 15N at the beginning of incubation. Mineralization of labelled organic N was measured by the appearance of label in the mineral N pool. Although gross N mineralization and gross N immobilization were increased in two soils between day 0 and day 7 following addition of unlabelled organic N solubilized by NH3(aq), there was no increase in net N mineralization. Solubilization of 15N-labelled organic N increased and the 15N enrichment of the soluble organic N decereased as the concentration of NH3(aq) added increased. A constant proportion of approximately one-quarter of the labelled organic N added at different rates to non-extracted soil was recovered in the mineral N pool after an incubation period of 14 days, and the availability ratios calculated from net N mineralization data were 1.1:1 and 2.1:1 for 111 and 186 mg added organic-N kg-1 soil, respectively, indicating that the mineralization of organic N was increased by solubilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00335824
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 26
    Digitale Medien
    Digitale Medien
    Growth and nitrogen nutrition of maize (Zea mays L.) in soil treated with the nitrification-inhibiting insecticide Baythroid (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 161-165 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words ANI ; Baythroid ; Cyfluthrin ; Insecticide ; 15N ; Nitrification ; N uptake ; Synthetic pyrethroid ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A pot experiment was conducted to compare the uptake and dry matter production potential of NH+ 4 and NO– 3 and to study the effect of Baythroid, a contact poison for several insect pests of agricultural crops, on growth and N uptake of maize (Zea mays L.). Nitrogen was applied as (15NH4)2SO4, K15NO3, or 15NH4NO3 and in one treatment Baythroid was combined with 15NH4NO3. Source of N had, in general, a nonsignificant effect on dry matter and N yield, but uptake of NO– 3 was significantly higher than that of NH+ 4 when both N sources were applied together. Substantial loss of N occurred from both the sources, with NH+ 4 showing greater losses. Baythroid was found to have a significant positive effect on dry matter yield of both root and shoot; N yield also increased significantly. Uptake of N from both the applied and native sources increased significantly in the presence of Baythroid and a substantial added nitrogen interaction (ANI) was determined. The positive effect of Baythroid was attributed to: (1) a prolonged availability of NH+ 4 due to inhibition of nitrification, (2) an increased availability of native soil N through enhanced mineralization, and (3) an enhanced root proliferation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336057
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 27
    Digitale Medien
    Digitale Medien
    A yield-independent, 15N-isotope dilution method to estimate legume symbiotic dependence without a non-N2-fixing reference plant (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 196-199 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Isotope dilution ; 15N ; Lupin ; Symbiotic dependence ; Biological N2 fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The proportional contribution of atmospheric N2 to the N nutrition of lupin (P atm) was estimated in a field experiment following addition of NH4Cl of KNO3 to unconfined microplots (1.5 m2) at 2.5 g N m-2 (10 atom% 15N). The integrated 15N enrichment, or ‘mean pool abundance’, of nitrate extracted from 0- to 15-cm samples taken under the lupin crop on eight occasion between 28 and 190 days after sowing was used as the reference criterion to estimate P atm by the 15N-isotope dilution technique. Estimates of P atm were similar to those obtained using canola as a non-fixing reference plant, but were higher than estimates obtained using a yield-dependent model. Use of ‘mean pool abundance’ obviates the need for a non-fixing reference plant, and the frequent sampling and isotope-ratio analysis of the legume biomass required with the yield-dependent model is unnecessary. However, further work is needed to validate a sampling strategy commensurate with the growth of the legume roots.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336063
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 28
    Digitale Medien
    Digitale Medien
    A yield-independent, 15N-isotope dilution method to estimate legume symbiotic dependence without a non-N2-fixing reference plant (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 196-199 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Isotope dilution ; 15N ; Lupin ; Symbiotic dependence ; Biological N2 fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The proportional contribution of atmospheric N2 to the N nutrition of lupin (P atm) was estimated in a field experiment following addition of NH4Cl of KNO3 to unconfined microplots (1.5 m2) at 2.5 g N m–2 (10 atom% 15N). The integrated 15N enrichment, or ’mean pool abundance‘, of nitrate extracted from 0- to 15-cm samples taken under the lupin crop on eight occasion between 28 and 190 days after sowing was used as the reference criterion to estimate P atm by the 15N-isotope dilution technique. Estimates of P atm were similar to those obtained using canola as a non-fixing reference plant, but were higher than estimates obtained using a yield-dependent model. Use of ’mean pool abundance‘ obviates the need for a non-fixing reference plant, and the frequent sampling and isotope-ratio analysis of the legume biomass required with the yield-dependent model is unnecessary. However, further work is needed to validate a sampling strategy commensurate with the growth of the legume roots.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336063
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 29
    Digitale Medien
    Digitale Medien
    Growth and nitrogen nutrition of maize (Zea mays L.) in soil treated with the nitrification-inhibiting insecticide Baythroid (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 161-165 
    Details
    ISSN: 1432-0789
    Schlagwort(e): ANI ; Baythroid ; Cyfluthrin ; Insecticide ; 15N ; Nitrification ; N uptake ; Synthetic pyrethroid ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A pot experiment was conducted to compare the uptake and dry matter production potential of NH inf4 sup+ and NO inf3 sup- and to study the effect of Baythroid, a contact poison for several insect pests of agricultural crops, on growth and N uptake of maize (Zea mays L.). Nitrogen was applied as (15NH4)2SO4, K15NO3, or 15NH4NO3 and in one treatment Baythroid was combined with 15NH4NO3. Source of N had, in general, a nonsignificant effect on dry matter and N yield, but uptake of NO inf3 sup- was significantly higher than that of NH inf4 sup+ when both N sources were applied together. Substantial loss of N occurred from both the sources, with NH inf4 sup+ showing greater losses. Baythroid was found to have a significant positive effect on dry matter yield of both root and shoot; N yield also increased significantly. Uptake of N from both the applied and native sources increased significantly in the presence of Baythroid and a substantial added nitrogen interaction (ANI) was determined. The positive effect of Baythroid was attributed to: (1) a prolonged availability of NH inf4 sup+ due to inhibition of nitrification, (2) an increased availability of native soil N through enhanced mineralization, and (3) an enhanced root proliferation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336057
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 30
    Digitale Medien
    Digitale Medien
    Volatilization losses of surface-applied urea nitrogen from Vertisols in the Indian semi-arid tropics (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 345-349 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Vertisol ; pH ; Cation exchange capacity ; Moisture ; Urea ; 15N ; Nitrogen losses ; Ammonia ; volatilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The N loss from Vertisols was estimated by measuring the loss of 15N-labelled urea N under conditions that promote NH3 volatilization. Urea granules were placed on the top of 150-mm deep soil columns (Vertisols) collected from three sites with a range in pH, electrical conductivity, and cation exchange capacity. There were two contrasting moisture treatments, one near field capacity (wet) and another with intermittent wetting of the soil surface before allowing the columns to dry (moist-dry). The results indicated that losses were influenced markedly by pH and moisture treatment, being 29.5, 33.5, and 33% from the wet soils and 37, 42, and 40.5% from the moist-dry soils with pH values of 7.7, 8.2, and 9.3, respectively. These observations clearly indicate that broadcasting of urea on the surface of Vertisols may cause substantial N losses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00334581
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 31
    Digitale Medien
    Digitale Medien
    Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 93-98 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Added nitrogen interaction ; Alkaline-hydrolysing fertilizer ; Aqua ammonia ; Gross N immobilization ; Gross N mineralization ; 15N ; Soluble organic N availability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Organic N solubilized by NH3(aq) was extracted from 15N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, gross N immobilization, and nitrification in soils with or without addition of unlabelled soluble organic N were estimated by models based on the dilution of the NH4 + or NO3 – pools, which were labelled with 15N at the beginning of incubation. Mineralization of labelled organic N was measured by the appearance of label in the mineral N pool. Although gross N mineralization and gross N immobilization were increased in two soils between day 0 and day 7 following addition of unlabelled organic N solubilized by NH3(aq), there was no increase in net N mineralization. Solubilization of 15N-labelled organic N increased and the 15N enrichment of the soluble organic N decereased as the concentration of NH3(aq) added increased. A constant proportion of approximately one-quarter of the labelled organic N added at different rates to non-extracted soil was recovered in the mineral N pool after an incubation period of 14 days, and the availability ratios calculated from net N mineralization data were 1.1:1 and 2.1:1 for 111 and 186 mg added organic-N kg–1 soil, respectively, indicating that the mineralization of organic N was increased by solubilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00335824
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 32
    Digitale Medien
    Digitale Medien
    Tree fallows: A comparison between five tropical tree species (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 50-56 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Agroforestry ; 15N ; Nitrogen fixation ; Phenolics ; 13C ; Tree fallows
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The natural abundance of 15N and 13C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N2-fixing), Leucaena leucocephala, Prosopis chilensis (both N2-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and δ15N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N2 fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the 15N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in δ13C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N2-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00335818
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 33
    Digitale Medien
    Digitale Medien
    Tree fallows: A comparison between five tropical tree species (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 50-56 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Key words Agroforestry ; 15N ; Nitrogen fixation ; Phenolics ; 13C ; Tree fallows
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The natural abundance of 15N and 13C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N2-fixing), Leucaena leucocephala, Prosopis chilensis (both N2-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and δ15N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N2 fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the 15N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in δ13C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N2-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00335818
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 34
    Digitale Medien
    Digitale Medien
    Extractability of 15N-labeled corn-shoot tissue in a sandy and a clay soil by 0.01 MCaCl2 method in laboratory incubation experiments (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 109-115 
    Details
    ISSN: 1432-0789
    Schlagwort(e): 15N ; Organic N ; Net mineralization of N ; CaCl2 extraction method ; Non-exchangeable NH inf4 sup+ ; Corn-shoot tissue ; Incubation method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Management of N fertilization depends not only on the mineral N measured at the beginning of the growing season but also on the status of the low-molecular-weight organic-N fraction. Our study was conducted to analyze how much of the 15N applied in labeled cornshoot tissue would be recovered in 0.01 M CaCl2-extractable 15N fractions and wheter a decrease in the CaCl2-extractable 15N fraction quantitatively followed the trend in net mineralization of the 15N applied in corn-shoot tissue during an incubation period. The effects of adding 15N-labeled young corn-shoot tissue to a sandy soil and a clay soil were investigated for 46 days in an aerobic incubation experiment at 25°C. The application of 80 mg N kg-1 soil in the form of labeled corn-shoot tissue (24.62 mg 15N kg-1 soil) resulted in a significant initial increase, followed by a decrease the labeled organic-N fraction in comparison with the untreated soils during the incubation. The labeled organic-N fraction was significantly higher in the sandy soil than in the clay soil until the 4th day of incubation. The decrease in labeled organic N in the sandy soil resulted in a subsequent increase in 15NO inf3 sup- during the incubation. Ammonification of applied plant N resulted in a significant increase in the 1 M HCl-extractable non-exchangeable 15NH inf4 sup+ fraction in the clay soik, owing to the vermiculite content. The 15N recovery was analyzed by the 0.01 M CaCl2 extraction method; at the beginning of the incubation experiment, recovery was 37.0% in the sandy soil and 36.7% in the clay soil. After 46 days of incubation, recovery increased to 47.2 and 43.8% in the sandy and clay soils, respectively. Net mineralization of the 15N applied in corn-shoot tissue determined after the 46-day incubation was 6.60 mg 15N kg-1 soil (=34.9% of the applied organic 15N) and 4.37 mg 15N kg-1 soil (=23.1% of the applied organic 15N) in the sandy and the clay soils, respectively. The decrease in the labeled organic-N fraction extracted by 0.01 M CaCl2 over the whole incubation period was 3.14 and 2.33 mg 15N kg-1 soil in the sandy and clay soil, respectively. These results indicate that net mineralization of 15N was not consistent with the decrease in the labeled organic-N fraction. This may have been due to the inability of 0.01 M CaCl2 to extract or desorb all of the applied organic 15N that was mineralized during the incubation period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384441
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 35
    Digitale Medien
    Digitale Medien
    Fate of urine nitrogen on mineral and peat soils in New Zealand (1996)
    Springer
    Plant and soil 178 (1996), S. 141-152 
    Details
    ISSN: 1573-5036
    Schlagwort(e): dentrification ; leaching ; lysimeter ; 15N ; ryegrass ; white clover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field lysimeter experiment was conducted over 150 days to examine the fate of synthetic urinary nitrogen (N) applied to peat and mineral soils, with and without a water table. At the start of the winter season, synthetic urine labelled with 15N, was applied at 500 kg N ha−1. Plant uptake, leaching losses and nitrous oxide (N2O) fluxes were monitored. Total plant uptake ranged from 11% to 35% of the urine-N applied depending on soil type and treatment. Plant uptake of applied N was greater in the presence of a water table in the mineral soil. Nitrate-N (NO3 --N) was only detected in leachates from the mineral soil, at concentrations up to 146 μg NO3 --N mL−1. Presence of a water table in the mineral soil reduced leaching losses (as inorganic-N) from 47% to 6%, incrased plant uptake and doubled apparent denitrification losses. In the peat soils leaching losses of applied urine-N as inorganic-N were low (〈5%). Losses of N as N2O were greater in the mineral soil than in the peat soils, with losses of 3% and 〈1% of N applied respectively after 100 days. Apparent denitrification losses far exceeded N2O losses and it is postulated that the difference could be due to dinitrogen (N2) loss and soil entrapment of N2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011172
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 36
    Digitale Medien
    Digitale Medien
    Nutrient inflow and root proliferation during the exploitation of a temporally and spatially discrete source of nitrogen in soil (1996)
    Springer
    Plant and soil 178 (1996), S. 185-192 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium ; heterogeneity ; inflow ; localised nutrient ; mineralisation ; 15N ; nitrate ; organic residue ; proliferation ; roots ; soil ; uptake ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract To obtain nutrients mineralised from organic matter in the soil, plants have to respond to its heterogeneous distribution. We measured the timing of nitrogen uptake by wheat from a localised, 15N labelled organic residue in soil, as well as the timing of changes in root length density. We calculated the rates of N uptake per unit root length (inflows) for roots growing through the residue and for the whole root system. A stimulated local inflow appeared to be the main mechanism of exploitation of the residue N during the first five days of exploitation. 8% of the N that the plants would ultimately obtain from the residue was captured in this period. Roots then proliferated in the residue. This, together with a rapidly declining N inflow, contributed to the capture, over the next seven days, of 63% of the N that the plants derived from the residue. After that time, massive root proliferation occurred in the residue, but relatively little further N was captured.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011582
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 37
    Digitale Medien
    Digitale Medien
    Nitrogen fixation by nine white clover cultivars in grazed pasture, as affected by nitrogen fertilization (1996)
    Springer
    Plant and soil 178 (1996), S. 193-203 
    Details
    ISSN: 1573-5036
    Schlagwort(e): cultivar, grazing ; 15N ; nitrogen fertilizer ; nitrogen fixation ; Trifolium repens
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Forage production and N2 fixation were determined for nine cultivars of white clover (Trifolium repens L.) grown with perennial ryegrass (Lolium perenne L.) and receiving nitrogen (N) fertilizer at either 0 or 390 kg N ha-1 yr-1. The site was grazed by sheep at 3 or 6 (in winter and summer) week intervals and N fertilizer was applied at 30 kg N ha-1 after each grazing. Annual white clover production showed a 2-fold variation between cultivars and was positively correlated with total pasture production in the 0 N treatment. Nitrogen fertilizer application increased average total pasture dry matter (DM) production from 12830 to 16010 kg ha-1 yr-1, but decreased average white clover production from 3600 to 2970 kg DM ha-1 yr-1. Fertilizer N application decreased annual N2 fixation from 111 to 47 kg N ha-1 (mean for all cultivars, using 15N dilution), with the decline occurring predominantly in spring and summer. The decrease in N2 fixation in spring from 47 to 18 kg N ha-1 was due largely to a decrease in clover DM production. In contrast, N application decreased average N2 fixation in summer from 36 to 14 kg N ha-1 due mainly to a large decrease in the proportion of clover N derived from atmospheric N2 (from 49 to 24%), with clover DM production falling by only 10%. Clover cultivars showed a variation in annual N2 fixation of about 3-fold under both N regimes. During winter and spring, the amount of N fixed by the different cultivars was determined predominantly by their DM production in both N regimes. In contrast, during summer and autumn there was a marked variation between cultivars in tolerance of N2 fixation to increased soil inorganic N due to N fertilizer application. This was evident from a significant cultivar × N interaction for the proportion (PN) of clover N derived from N2 fixation. During summer/autumn, PN for Kopu was similar in the 0 and 390 N treatments, whereas PN declined by up to two-thirds for the other cultivars. Consequently, in summer/autumn the amount of N fixed by Kopu decreased by only 20% (from 65 to 52 kg N ha-1) due to N application whereas it decreased by 40–80% (to 15–34 kg N ha-1) for the other cultivars. Thus, N2 fixation during winter/spring was highest for the most productive large-leaved cultivars (Kopu, Aran and Pitau) either in the absence or presence of added N. In contrast, in summer/autumn the cultivars differed in tolerance to added N, and N2 fixation in the 390 N treatment was higher for the more tolerant cultivar Kopu than for the other cultivars.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011583
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 38
    Digitale Medien
    Digitale Medien
    Rainfed vetch-barley mixed cropping in the Syrian semi-arid conditions (1996)
    Springer
    Plant and soil 183 (1996), S. 137-148 
    Details
    ISSN: 1573-5036
    Schlagwort(e): barley ; legume ; mixed crop ; monocrop ; N2 fixation ; 15N ; vetch
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment on vetch and barley grown in monoculture and in mixed culture was conducted under rain-fed conditions throughout two growing seasons. Plants were either subjected to three sequential harvests, or were harvested only once, at physiological maturity. Our results showed the advantage of a mixed cropping system of vetch and barley over sole cropping under rainfed conditions in terms of dry matter production, total nitrogen content, and land use efficiency expressed as land equivalent ratio (LER). This advantage was more pronounced in the plants harvested once at the end of the season than those subjected to the three successive harvests. Based on this result, a single seasonal rather than several harvests would be recommended under similar rainfed conditions. Nitrogen fixation in vetch measured by the15N-isotope dilution method, varied with the number of harvests and with cropping system. The percentage of N derived from the atmosphere (%Ndfa) of vetch in mixed culture was in most cases higher than in monoculture. The poor competitiveness of vetch for soil N uptake was responsible for the higher soil N uptake by barley and therefore, a higher %Ndfa in vetch. Positive and high final nitrogen balance was observed in the mixture. We excluded, under the current experimental conditions, the possibility of N-transfer from vetch to barley.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02185573
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 39
    Digitale Medien
    Digitale Medien
    N2-Fixation, nodule efficiency and biomass accumulation after two years in three Chilean legume trees and Tagasaste Chamaecytisus proliferus subsp. palmensis (1996)
    Springer
    Plant and soil 179 (1996), S. 131-140 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Acacia caven ; agroforestry ; Chamaecytisus proliferus subsp. palmensis ; isotope dilution ; 15N ; nitrogen fixation ; nodule efficiency ; Prosopis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Initial results of a long-term field experiment are presented for the above and below-ground biomass accumulation after two years, as well as root nodulation, nodule efficiency (g N fixed/g nodules) and biological N2 fixation (using the 15N isotope dilution method) of four N2-fixing tree species (NFTs) grown in the subhumid mediterranean-climate zone of central Chile. Two non-legume tree species, Fraxinus excelsior and Schinus polygamus, were used as reference plants for the isotope dilution calculations. Over two years, Tagasaste (Chamaecytisus proliferus subsp. palmensis, a Papilionoideae from the Canary Islands), produced 10 to 20 times more biomass than the other three NFTS (Acacia caven, Prosopis alba and P. chilensis); all Mimosoideae native to Chile, and nodulation and nitrogen fixed were an order of magnitude higher as well. At the end of the second year, the percentage of N derived from N2 fixation (%Ndfa) in Tagasate averaged 85.6, equivalent to ca. 49.1 g N fixed per tree. For all four NFTs, however, %Ndfa, nodule efficiency, and total N accumulation varied from one year to the next; caution is thus required in interpreting or predicting NFT performance over the long term, even if Tagasaste can already be considered a highly promising NFT for central Chile.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011650
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 40
    Digitale Medien
    Digitale Medien
    Inhibition of N2 fixation by white clover (Trifolium repens L.) at low concentrations of NO inf3 sup− in flowing solution culture (1996)
    Springer
    Plant and soil 180 (1996), S. 287-295 
    Details
    ISSN: 1573-5036
    Schlagwort(e): inhibition ; 15N ; nitrate ; nitrogen fixation ; Trifolium repens ; uptake ; white clover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The impact of sustained low external concentrations of NO 3 − (0, 10, 100 and 1000 mmol m−3) on plant growth and the relative acquisition of N through N2 fixation and NO 3 − uptake by established, nodulated white clover (Trifolium repens L. cv. Blanca) was studied over 28 days in flowing solution culture. Nitrogen fixation was measured by N difference and 15N dilution methods. Plants supplied with NO 3 − achieved higher relative growth rates (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\]=0.091 d−1) compared with ‘control’ plants dependent on N2 fixation (0.073 d−1). Nitrate plants showed progressive increases in shoot: root d.w. ratios from 4 to 6.5–7.6 between days 0–28, compared with 5.1 on day 28 for control plants. Increases in both nodule d.w. and numbers per plant were inhibited after day seven at all concentrations of NO 3 − . The severity of inhibition of N2 fixation increased with increasing NO 3 − concentration and with time. The total amounts of N2 fixed per plant between days 0–7 after supplying 10, 100 and 1000 mmol m−3 NO 3 − , respectively, were 37–39, 28–30 and 0–13%, of the total N acquired. Between days 7–28 the proportional contributions of N2 fixation to total N acquisition declined to 3, 0.5 and 0%, respectively, in these treatments. The corresponding mean specific rates of N2 fixation between days 0–7 were, respectively, 5.4, 3.2, and 2.0 mmol N d−1 g−1 nodule d.w., compared with 7.9 mmol N d−1 g−1 nodule d.w. for zero NO 3 − plants. There was no evidence of a transitory increase in N2 fixation following the addition of NO 3 − , even at the lowest supply concentration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00015312
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 41
    Digitale Medien
    Digitale Medien
    The effect of fertilizer placement on nitrogen uptake and yield of wheat and maize in Chinese loess soils (1996)
    Springer
    Nutrient cycling in agroecosystems 47 (1996), S. 81-91 
    Details
    ISSN: 1573-0867
    Schlagwort(e): China ; Loess Plateau ; maize ; 15N ; Nitrogen ; urea ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field trials were carried out to study the fate of15N-labelled urea applied to summer maize and winter wheat in loess soils in Shaanxi Province, north-west China. In the maize experiment, nitrogen was applied at rates of 0 or 210 kg N ha−1, either as a surface application, mixed uniformly with the top 0.15 m of soil, or placed in holes 0.1 m deep adjacent to each plant and then covered with soil. In the wheat experiment, nitrogen was applied at rates of 0, 75 or 150 kg N ha−1, either to the surface, or incorporated by mixing with the top 0.15 m, or placed in a band at 0.15 m depth. Measurements were made of crop N uptake, residual fertilizer N and soil mineral N. The total above-ground dry matter yield of maize varied between 7.6 and 11.9 t ha−1. The crop recovery of fertilizer N following point placement was 25% of that applied, which was higher than that from the surface application (18%) or incorporation by mixing (18%). The total grain yield of wheat varied between 4.3 and 4.7 t ha−1. In the surface applications, the recovery of fertilizer-derived nitrogen (25%) was considerably lower than that from the mixing treatments and banded placements (33 and 36%). The fertilizer N application rate had a significant effect on grain and total dry matter yield, as well as on total N uptake and grain N contents. The main mechanism for loss of N appeared to be by ammonia volatilization, rather than leaching. High mineral N concentrations remained in the soil at harvest, following both crops, demonstrating a potential for significant reductions in N application rates without associated loss in yield.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01985721
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 42
    Digitale Medien
    Digitale Medien
    Screening woody and shrub legumes for growth, nodulation and nitrogen-fixation potential in two contrasting soils (1996)
    Springer
    Agroforestry systems 33 (1996), S. 137-152 
    Details
    ISSN: 1572-9680
    Schlagwort(e): woody legumes ; screening ; Alfisol ; Ultisol ; N2-fixation ; 15N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In order to identify for alley cropping new candidate species with high biomass and nitrogen-fixing potential, a screening study was conducted on ten woody and shrub legumes (Acacia auriculiformis, Albizia lebbeck, Gliricidia sepium, Leucaena diversifolia, L. leucocephala cv. K28 and cv. K636, Lonchocarpus sericeus, Cajanus cajan, Crotalaria juncea and Tephorsia candida) for 6 months using an acid Ultisol and a non-acid Alfisol. A wide interspecific variability of legumes appeared within soil types, and there were significant species-by-soil interactions for many parameters in this study. In the acid Ultisol, plant growth in height and grith, nodule numbers, nitrogen yield and N2-fixing potential were significantly (P = 0.05) lower than those in the Alfisol. While Albizia lebbeck was outstanding in both acid and non-acid soil conditions for most performance criteria, L. leucocephala cv. K28 was most sensitive to soil acidity with 41.7% of total nitrogen yield in the Ultisol relative to that accumulated in the Alfisol. In addition to L. leucocephala cv. K28 and G. sepium, the most common hedgerow species, A. lebbeck, L. leucocephala cv. K636, L. diversifolia on Alfisol, and A. lebbeck, L. leucocephala cv. K636, L. diversifolia, Tephrosia candida and Cajanus cajan on acid Ultisol, could be considered promising and thus, worthy of further site adaptability trials.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00213646
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 43
    Digitale Medien
    Digitale Medien
    Biological nitrogen fixing capacity and biomass production of different understorey pastures in a Pinus radiata-pasture agroforestry system in New Zealand (1996)
    Springer
    Agroforestry systems 34 (1996), S. 33-49 
    Details
    ISSN: 1572-9680
    Schlagwort(e): nitrogen fixation ; 15N ; %Ndfa ; ryegrass+clover pasture ; silvopastoral system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Quantitative field measurements of biological nitrogen fixation (BNF) and biomass production by four different understorey pastures in a Pinus radiata-pasture agroforestry system were determined over a period of one year. The trees were two years old at the beginning of this study and the understorey pastures were being cut and removed for silage. The BNF was determined using the 15N dilution technique. Pastures of ryegrass+clover, cocksfoot+clover, phalaris+clover and lucerne were used. Substantial amounts of BNF were found (71 to 230 kg N ha−1 year−1) with lucerne showing the highest N fixation. However, lucerne derived only 71 to 72% of its N from the atmosphere (%Ndfa) during the spring/summer period compared to 83–97% with clovers, thus the net N demand from the soil was substantially higher with lucerne. This caused increased N stress to the trees. Clover in ryegrass+clover pasture fixed more N than the other grass+clover pastures. Although pasture position in relation to trees did not affect annual pasture total DMY and %Ndfa, pastures north of tree row grew better than those in other positions. Trees significantly affected the BNF of legumes and the botanical composition of pastures with highest BNF and legume production occurring in pastures midway between two rows of trees. These results suggest that it would be advantageous to evaluate different legumes and grasses for tolerance of shade and moisture stress in future studies. As the trees studied were only 1.5 to 3 m in height, their effects on BNF, seasonal pasture biomass production and botanical composition are expected to increase with tree dominance in the ecosystem with time. Amounts of N fixed were related to the productivity (i.e. dry matter and N yield) and seasonal persistence of the legumes. The productivity was high in spring and summer and low in autumn and winter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00129631
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 44
    Digitale Medien
    Digitale Medien
    Mineralization of carbon and nitrogen from fresh and anaerobically stored sheep manure in soils of different texture (1995)
    Springer
    Biology and fertility of soils 19 (1995), S. 29-35 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Ammonium sulphate ; Biomass N ; Clay CO2 ; Gross mineralization ; 15N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A sandy loam soil was mixed with three different amounts of quartz sand and incubated with (15NH4)2SO4 (60 μg N g-1 soil) and fresh or anaerobically stored sheep manure (60 μg g-1 soil). The mineralization-immobilization of N and the mineralization of C were studied during 84 days of incubation at 20°C. After 7 days, the amount of unlabelled inorganic N in the manure-treated soils was 6–10 μg N g-1 soil higher than in soils amended with only (15NH4)2SO4. However, due to immobilization of labelled inorganic N, the resulting net mineralization of N from manure was insignificant or slightly negative in the three soil-sand mixtures (100% soil+0% quartz sand; 50% soil+50% quartz sand; 25% soil+75% quartz sand). After 84 days, the cumulative CO2 evolution and the net mineralization of N from the fresh manure were highest in the soil-sand mixutre with the lowest clay content (4% clay); 28% fo the manure C and 18% of the manure N were net mineralized. There was no significant difference between the soil-sand mixtures containing 8% and 16% clay, in which 24% of the manure C and -1% to 4% of the manure N were net mineralized. The higher net mineralization of N in the soil-sand mixture with the lowest clay content was probably caused by a higher remineralization of immobilized N in this soil-sand mixture. Anaerobic storage of the manure reduced the CO2 evolution rates from the manure C in the three soil-sand mixtures during the initial weeks of decomposition. However, there was no effect of storage on net mineralization of N at the end of the incubation period. Hence, there was no apparent relationship between net mineralization of manure N and C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336343
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 45
    Digitale Medien
    Digitale Medien
    Nitrogen fixation and beneficial effects of some grain legumes and green-manure crops on rice (1995)
    Springer
    Biology and fertility of soils 19 (1995), S. 49-54 
    Details
    ISSN: 1432-0789
    Schlagwort(e): N2 fixation ; N supplying potential ; Grain legumes ; Green manuring ; 15N ; Wetland rice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Studies were conducted on paddy soils to ascertain N2 fixation, growth, and N supplying ability of some green-manure crops and grain legumes. In a 60-day pot trial, sunhemp (Crotalaria juncia) produced a significantly higher dry matter content and N yield than Sesbania sesban, S. rostrata, cowpeas (Vigna unguiculata), and blackgram (V. mungo), deriving 91% of its N content from the atmosphere. Dry matter production and N yield by the legumes were significantly correlated with the quantity of N2 fixed. In a lowland field study involving sunhemp, blackgram, cowpeas, and mungbean, the former produced the highest stover yield and the stover N content, accumulating 160–250 kg N ha-1 in 60 days, and showed great promise as a biofertilizer for rice. The grain legumes showed good adaptability to rice-based cropping systems and produced a seed yield of 1125–2080 kg ha-1, depending on the location, species, and cultivar. Significant inter- and intraspecific differences in the stover N content were evident among the grain legumes, with blackgram having the highest N (104–155 kg N ha-1). In a trial on sequential cropping, the groundnut (Arachis hypogaea) showed a significantly higher N2 fixation and residual N effect on the succeeding rice crop than cowpeas, blackgram, mungbeans (V. radiata), and pigeonpeas (Cajanus cajan). The growth and N yield of the rice crop were positively correlated with the quantity of N2 fixed by the preceding legume crop.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336346
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 46
    Digitale Medien
    Digitale Medien
    Dynamics of nodulation, nitrogen fixation, nitrogen use and biomass yield over time in pot-grown Leucaena leucocephala (Lam.) de Wit (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 163-168 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Leucaena ; Nodulation ; Nitrogen fixation ; Nitrogen use ; 15N ; Time course
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The dynamics of nodulation, N2-fixation and N use in Leucaena leucocephala cv. K28 over time was investigated in a screenhouse at 4, 8, 12 and 16 months after planting (MAP) using the 15N-labelling method. Leucaena had a consistently increasing pattern of nodulation, dry biomass and nitrogen yield. A sharp rise in nodulation was observed between 12 and 16 MAP, whereas for biomass, N accumulation and N2-fixation, and N2-fixation, an upward surge occurred between 4 and 12 months. Nodulation, N accumulation, N2-fixation and biomass yield all peaked at 16 MAP. Along with the steady increase in N2-fixation throughout the 16-month growth period, the % N derived from the atmosphere rose from 17.9% to 61.5%, 70.1% and 74%, equivalent to 191, 1623, 2395 and 3385 mg N2 fixed plant-1 at 4, 8, 12 and 16 MAP, respectively. Nitrogen assimilation from soil and fertilizer decreased inversely to the increase in symbiotic nitrogen fixation with time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336553
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 47
    Digitale Medien
    Digitale Medien
    Biological interactions between soil nitrogen and alkaline-hydrolysing nitrogen fertilizers (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 41-48 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Added nitrogen interaction ; Ammonia fixation ; 15N ; Immobilization ; Fertilizer-induced solubilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Added N interactions were measured in four soil incubated with 15N-labelled urea or diammonium phosphate. The use of biologically active, γ-irradiated, or reinoculated γ-irradiated samples allowed us to separate added N interactions due to chemical and biological processes, and to distinguish real interactions from apparent effects. Real biologically mediated added N interactions were observed in one soil for both fertilizer sources and in three soils amended with urea. These real interactions increased with the N fertilizer rate, but did not differ significantly between N sources. Fertilizer-induced unlabelled organic N in soil extracts declined during incubation in both sterile and non-sterile samples, but the temporal decline was higher in biologically active soil. Changes in fertilizer-induced unlabelled organic N in the extracts of three soils attributed to biological processes were similar to the measured real biologically mediated added N interactions. The results are consistent with the hypothesis that real biologically mediated added N interactions arise from the mineralization of soil organic N solubilized by alkaline-hydrolysing N fertilizers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00307839
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 48
    Digitale Medien
    Digitale Medien
    A conceptual assessment of the importance of denitrification as a source of soil nitrogen loss in tropical agro-ecosystems (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 139-148 
    Details
    ISSN: 1573-0867
    Schlagwort(e): denitrification ; methods ; 15N ; nitrate ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper attempts to answer the question: is denitrification a major route of N loss from tropical agro-ecosystems? This question turns out to be very difficult to answer due to a severe shortage of data on this process for tropical agro-ecosystems other than rice. Given this lack of data, I approach this question by analyzing data on denitrification and nitrous oxide flux in tropical native forest and pasture soils and attempt to make some conclusions and pose some hypotheses about the significance of denitrification in tropical agricultural soils. I also briefly review methods for measuring denitrification. The data analysis suggests that denitrification in tropical forest soils is strongly influenced by the nature and amount of soil C and N turnover. Studies to examine differences in denitrification in different tropical agricultural systems should focus on the effects of system management on C and N turnover. The data analysis also suggests that, just as in temperate regions, denitrification may not be a significant route of N loss from most tropical agricultural systems. However, field studies are necessary to determine if this is actually the case.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750508
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 49
    Digitale Medien
    Digitale Medien
    Estimation of the contribution of biological N2 fixation to twoPhaseolus vulgaris genotypes using simulation of plant nitrogen uptake from15N-labelled soil (1995)
    Springer
    Nutrient cycling in agroecosystems 45 (1995), S. 169-185 
    Details
    ISSN: 1573-0867
    Schlagwort(e): 15N ; non-nod beans ; quantification of N2 fixation ; reference crops ; simulation technique ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A technique for the application of the15N isotope dilution technique for the quantification of plant associated biological nitrogen fixation (BNF) was tested and applied to quantify the BNF contribution to two genotypes ofPhaseolus vulgaris. The technique makes use of sequential measurements of the15N enrichment of soil mineral N, and the uptake of labelled N by the “N2-fixing” plant, to simulate its uptake of soil N (the “soil to plant simulation” technique). The test was made with two non-N2-fixing crops (non-nodulating beans and wheat) and two bean genotypes (PR 923450 and Puebla 152), at two levels of N fertilizer addition (10 and 40 kg N ha−1), to compare the actual N uptake with that simulated from the soil and crop15N data. The simulation of the soil N uptake by the non-nod bean crop using this “soil to plant simulation” technique underestimated by 20 to 30% the true N uptake, suggesting that the mineral N extracted from soil samples taken from the 0–15cm layer had a higher15N enrichment than that N sampled by the roots of this crop. In the case of the wheat crop the simulation resulted in a much greater underestimation of actual N uptake. In general the results using this technique suggested that BNF inputs to the bean cultivars was higher than would be expected from the nodulation and acetylene reduction data, except for the early PR beans in the 40 kg N ha−1 treatment. In this case the total N and simulated soil N accumulation were well matched suggesting no BNF inputs. An allied technique (the “plant to plant simulation technique”) was proposed where the15N enrichrnent of soil mineral N was simulated from the data for total N and labelled N accumulation taken from sequential harvests of either of the non-N2 -fixing control crops. This was then utilized in combination with the labelled N uptake data of the other crop to simulate its soil N uptake. However, the results using either technique indicated that the wheat and non-nod or nodulating beans exploited pools of N in the soil with completely different15N enrichments probably due to differences in exploitation of the soil N with depth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00748587
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 50
    Digitale Medien
    Digitale Medien
    Assessment of biological nitrogen fixation (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 33-41 
    Details
    ISSN: 1573-0867
    Schlagwort(e): acetylene ; 15N ; nodules ; reference plant ; ureide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The four commonly used methods for measuring biological nitrogen fixation (BNF) in plants are: the total nitrogen difference (TND) method, acetylene reduction assay (ARA) technique, xylem-solute (or ureide production) method and the use of15N labelled compounds. The TND method relies on a control non-N2-fixing plant to estimate the amount of N absorbed by the fixing plant from soil. It is one of the simplest and least expensive methods, but works best under low soil N conditions. The ARA technique measures the rate of acetylene conversion to ethylene by the N2-fixing enzyme, nitrogenase. The ethylene produced can then be converted into N2 fixed, using a conversion ratio, originally recommended as 3. Although the method is inexpensive and highly sensitive, its major disadvantages are, the short-term nature of the assays, the doubtful validity of always using a conversion ratio of 3 and the auto-inhibition of acetylene conversion to ethylene. The ARA technique is therefore not a method of choice for measuring BNF. The xylem-solute technique can be used to measure BNF for those species that produce significant quantities of ureide as product of BNF. Although simple and relatively inexpensive, it is an instantaneous assay and also needs to be calibrated against a known method. The most serious limitation is, that only a small proportion of N2-fixing plants examined are ureide exporters, and the method is therefore not widely applicable. The15N methods, classified into the isotope dilution and A-value methods, appear to be the most accurate, but also the most expensive. They involve labelling soil with15N fertilizer and using a non-N2-fixing reference plant to measure the15N/14N ratio in the soil. The15N isotope dilution approach is both operationally and mathematically simpler than the A-value approach. To limit potential errors in the selection of reference crops, it is recommended to use15N labelled compounds or soil labelling methods that result in the slow release of15N or the slow decline of15N/14N ratio in the soil. Additionally, the use of several reference plants rather than a single one can improve the accuracy of the results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750498
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 51
    Digitale Medien
    Digitale Medien
    15N isotope dilution techniques to study soil nitrogen transformations and plant uptake (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 185-192 
    Details
    ISSN: 1573-0867
    Schlagwort(e): 15N ; nitrogen ; soil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The use of15N as a tracer in soil/plant research is examined. The limitations of the so-called Ndff approach are discussed to show the need to consider not just the fate of the added label but also the path that was followed and the rate of the transformation. The development of15N isotope dilution techniques to determine gross rates of nitrogen transformation in soil is reviewed with some indications as to the further development of the approach.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750513
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 52
    Digitale Medien
    Digitale Medien
    Fate of CO(NH2)2-15N applied to taro (Colocasia esculenta var.esculenta) in an acid Vertisol of Trinidad (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 109-115 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Colocasia esculenta var.esculenta ; crop uptake ; 15N ; soil management ; tropical soils ; urea ; Vertisols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Vertisols are an important natural resource, particularly in the developing world, but a greater understanding of their chemical characteristics with special reference to the fate of applied N is needed for their greater sustainable use. The Bejucal clay (Chromic Dystraquerts, very fine, mixed, acid) is an important agricultural soil in North Trinidad and a series of studies were undertaken on it to determine the optimum rate and the best time of application and to quantify the efficiency of applied N using CO(NH2)2-15N and taro, commonly called dasheen locally, (Colocasia esculenta var.esculenta), as a test crop. The optimum rate was found to be 280 kg N ha−1 for corm production from a field experiment, laid out in a randomised incomplete block design. This corresponded to an apparent recovery at 10 per cent when CO(NH2)2 was applied at 14 days after planting (DAP). Generally, a decrease in N uptake with increasing levels and later application times was observed. Another field experiment which employed15N applied at 14, 56, and 112 DAP showed that15N applied at 112 DAP corresponded to the highest15N level in the plant tissue. A green house experiment conducted to determine the efficiency of the use of the applied N showed the highest recovery of approximately 49 per cent at a rate equilavent to 280 kg N ha−1 with efficiencies of 43 and 40 per cent at the 140 and 420 kg N ha−1 of applied N levels, respectively. A single application at 14 DAP resulted in an efficiency of 41 per cent compared to 44 and 47 per cent for the 2 split and 3 split applications, respectively. Split applications increased N uptake but without a corresponding increase in yield. These studies showed that N applied as CO(NH2)2 at 280 kg N ha−1 at 14 DAP is optimum for upland taro production under conditions of the Bejucal clay. Under normal field conditions surface washing may be the most important N loss pathway but when excessive fertilizers are used then the gaseous pathways may also contribute to N losses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750504
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 53
    Digitale Medien
    Digitale Medien
    Soil, plant and atmospheric conditions as they relate to ammonia volatilization (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 149-158 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Micrometeorology ; N flux ; livestock waste ; NH3 ; 15N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Gaseous ammonia (NH3) transport is an important pathway in the terrestrial N cycle. In the atmosphere NH3 neutralizes airborne acids and is a major factor determining air quality and acid rain deposition patterns. Redeposition of atmospheric NH3 plays an important role in the N balance of natural ecosystems and has been implicated in forest decline, plant species change and eutrophication of surface water. Much of the N in soil-plant animal systems can be lost to the atmosphere, particularly with surface applied livestock waste, or urea and anhydrous ammonia fertilizers. Plants can have a significant impact on NH3 transport because they can both absorb and desorb atmospheric NH3. Under conditions of low soil N or high atmospheric NH3 concentrations, plants absorb NH3. Under conditions of high soil N or low atmospheric NH3 concentrations, plants volatilize NH3. This article discusses methods for evaluating NH3 transport in the filed, the rate of NH3 volatilized from fertilizer application, and the effects of plants on net NH3 transport.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750509
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 54
    Digitale Medien
    Digitale Medien
    The role ofAzolla in curbing ammonia volatilization from flooded rice systems (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 165-174 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Anabaena ; cropping systems ; fertilizer management ; integrated nitrogen management ; 15N ; nitrogen balance ; Oryza sativa ; urea ; wetlands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract By the year 2020, an additional 300 million tons of rice are needed annually to meet the demands of a growing population. If our natural resource base is to be preserved, intensification strategies should rely on integrated nutrient management, making full use of biological nitrogen fixation. TheAzolla-Anabaena complex is amongst the most effective systems of fixing nitrogen. In this paper we present evidence from greenhouse studies on the potential ofAzolla to curb the volatilization of NH3 following the application of urea to a mixedAzolla-rice culture, providing a new incentive for developing ways of integratingAzolla in intensive rice cultivation systems. The results of a series of short term greenhouse experiments show that a full cover ofAzolla can significantly reduce losses of applied urea-N from 45 and 50% to 20 and 13% for the 30 and 60 kg N ha−1 treatments, respectively. About one-quarter of the applied N was tied up in theAzolla biomass. The applied N inhibitedAzolla growth as well as the amount of N fixed. Inoculation with smaller quantities ofAzolla allowing for more vigorousAzolla multiplication was equally effective in reducing NH3 volatilization and doubled the amount of15N tied-up byAzolla. The reduction in NH3 volatilization is largely related to the depression byAzolla of the floodwater pH, which in its absence may reach values between 9 and 10 as a result of algal activity. Early rice growth responded positively to urea as well as the large quantities of appliedAzolla and increased the yield potential of the crop. Smaller quantities ofAzolla alone were not effective in this regard. The conservation of fertilizer N byAzolla, particularly when it fully covered the water, was reflected in a synergistic effect on rice dry matter production, amounting to 9% at the 30 kg N rate and 16% at the 60 kg N rate. In all likelihood this interaction is attributable to the higher efficiency of the applied N. The benefits ofAzolla in conserving basal urea-N even in small quantities (200-500 kg fresh material ha−1), outweighed competition for the applied N and may be as important as its BNF. The most promising integratedAzolla/rice management systems emerging from our studies should be given further attention under field conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750511
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 55
    Digitale Medien
    Digitale Medien
    Urea-N uptake by dasheen (Colocasia esculenta L. Schott) in relation to the fertilizer placement method (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 205-214 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Colocasia esculenta ; fertilizer efficiency ; fertilizer management ; 15N ; urea transformations ; volatilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Urea has become the most important N carrier in many parts of the world and its reaction when added to soil is unique in many ways. Two field experiments were therefore undertaken using15N to investigate the uptake efficiency of the added urea-15N which was banded in Experiment I and broadcast in Experiment II. In both experiments the uptake efficiencies were not affected by N-rate and cropping system (Exp. I) or crop residue management (Exp. II) and averaged 17.4 and 16.9% respectively. These low values were supported by evidences of high losses; high pH increases following urea application (volatilization), downward movement of N (leaching), and cycles of waterlogged and well drained conditions in the soil (de-nitrification). Evidence of leaching at least down to 30 cm in the profile was observed in the first experiment where urea was banded but not in experiment II where it was broadcast. The proportion of N in the crop that was derived from added urea (%Ndff) was 57.7% and 36.4% in experiments I and II respectively, suggesting that band application resulted in a higher proportion of the added N in the root zone compared to that for broadcast application. The results indicate the need to investigate other management strategies, such as higher application frequencies and placement closer to the root zone, in order to improve the uptake efficiency of added urea-N in upland rainfed dasheen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750515
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 56
    Digitale Medien
    Digitale Medien
    Nitrogen fixation of and N transfer from cowpea, mungbean and groundnut when intercropped with maize (1995)
    Springer
    Nutrient cycling in agroecosystems 40 (1995), S. 41-48 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Arachis hypogaea ; intercropping ; maize ; N2 fixation ; N-transfer ; 15N ; Vigna radiata ; Vigna unguiculata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Grain legumes are used widely in intercropping systems. However, quantitative and comparative data available as to their N2 fixation and N beneficial effect on the companion crop in intercropping systems are scarce. Hence, studies were conducted to ascertain the above when cowpea (Vigna unguiculata L.), mungbean (Vigna radiata L.) and groundnut (Arachis hypogaea L.) were intercropped with maize. The study was15N-aided and made outdoors in basins (30 L) filled with 38 kg of soil.15N labelling was effected by incorporating15N-tagged plant material or applying15N-labelled fertilizer along with sucrose to stabilize15N enrichment in the soil during the experimental period. Intercropped groundnut fixed the highest amount of nitrogen from the atmosphere (i.e. 552 mg plant−1), deriving 85% of its N from the atmosphere. Intercropped cowpea and mungbean fixed 161 and 197 mg N plant−1, obtaining 81% and 78% of their N content from the atmosphere, respectively. The proportion of N derived by maize from the associated legume varied from 7-11% for mungbean, 11–20% for cowpea and 12–26% for groundnut which amounted to about 19–22, 29–45 and 33–60 mg N maize plant−1, respectively. The high nitrogen fixation potential of groundnut in dual stands and its relatively low harvest index for N have apparently contributed to greater N-benefical effect on the associated crop.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00749861
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 57
    Digitale Medien
    Digitale Medien
    Measurements of abundances of 15N and 13C as tools in retrospective studies of N balances and water stress in forests: A discussion of preliminary results (1995)
    Springer
    Plant and soil 168-169 (1995), S. 125-133 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 13C ; forests ; 15N ; nitrogen saturation ; water stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Preliminary attempts to make retrospective studies of N balances and water stress in forest fertilization experiments by analyzing changes in the abundances of 15N and 13C, respectively, are discussed. Most evidence is from the Swedish Forest Optimum Nutrition Experiments, which have been running for two decades. Annual additions of N have been given either alone or in combination with other elements, notably P and K, every third year. Processes leading to loss of N, e.g. volatilization of ammonia, nitrification followed by leaching or denitrification, and denitrification alone, discriminate against the heavy isotope 15N. A correlation was found between fractional losses of added N and the change in δ15N (‰) during 19 years in current needles in a Scots pine forest, irrespective of source of N. Isotope effects were larger on urea than on ammonium nitrate plots (2 as compared to 9 δ15N (‰)) because of ammonia volatilization and higher rates of nitrification. They developed gradually over time, which opens possibilities to analyse the development of N saturation. However, the analysis may be confounded by shifts in 15N abundance of fertilizer N. In another trial, N isotope effects could be seen in both plants and soils 10 years after the last fertilization; they were smaller in soils because of a large pretreatment memory effect, but we expect them to persist there for decades. The enzyme RuBisCo discriminates strongly against the heavy isotope 13C during photosynthesis, but this effect becomes less expressed as stomata close because of water stress. The supply of N may also affect the δ13C (‰) via effects on rates of photosynthesis, and the source of N may have an influence directly via non-RubisCo carboxylations, and indirectly via effects on water use efficiency. In a trial with Norway spruce, the effect of N fertilization on the δ13C (‰) of current needles was strongly correlated with production and weakly so with foliar biomass a dry year, but not a wet year. This suggested that these variations are primarily related to induced differences in the balance between supply and demand for water. Hence, studies of {au13}C abundance can disentangle the role of water as such from its effects on mineralization of N and flow of N.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00029321
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 58
    Digitale Medien
    Digitale Medien
    Nitrogen fixation in Faidherbia albida, Acacia raddiana, Acacia senegal and Acacia seyal estimated using the 15N isotope dilution technique (1995)
    Springer
    Plant and soil 172 (1995), S. 175-180 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Acacia raddiana ; Acacia senegal ; Acacia seyal ; Faidherbia albida ; isotope dilution ; 15N ; nitrogen fixation ; Parkia biglobosa reference tree ; Tamarindus indica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A pot experiment was conducted in a greenhouse using the 15N isotope dilution method and two reference plants, Parkia biglobosa and Tamarindus indica to estimate nitrogen fixed in four Acacia species: A raddiana, A. senegal, A. seyal and Faidherbia albida (synonym Acacia albida). For the reference plants, the 15N enrichments in leaves, stems and roots were similar. With the fixing plants, leaves and stems had similar 15N enrichments; they were higher than the 15N enrichment of roots. The amounts of nitrogen fixed at 5 months after planting were similar using either reference plant. Estimates of the percentage of N derived from fixation (%Ndfa) for the above ground parts, in contrast to %Ndfa in roots, were similar to those for the whole plant. However, none of the individual plant parts estimated accurately total N fixed in the whole plant, and excluding the roots resulted in at least 30% underestimation of the amounts of N fixed. Between species, differences in N2 fixation were observed, both for %Ndfa and total N fixed. For %Ndfa, the best were A. seyal (average, 63%) and A. raddiana (average, 62%), being at least twice the %Ndfa in A. senegal and F. albida. Because of its very high N content, A. seyal was clearly the best in total N fixed, fixing 1.62 g N plant−1 compared to an average of 0.48 g N plant−1 for the other Acacia species. Our results show the wide variability existing between Acacia species in terms of both %Ndfa and total N fixed: A. seyal was classified as having a high N2 fixing potential (NFP) while the other Acacia species had a low NFP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011319
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 59
    Digitale Medien
    Digitale Medien
    Mineralization-immobilization and plant uptake of nitrogen as influenced by the spatial distribution of cattle slurry in soils of different texture (1995)
    Springer
    Plant and soil 173 (1995), S. 283-291 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium ; animal manure ; injection ; 15N ; N utilization ; ryegrass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of incorporating cattle slurry in soil, either by mixing or by simulated injection into a hollow in soil, on the ryegrass uptake of total N and 15NH4 +-N was determined in three soils of different texture. The N accumulation in Italian ryegrass (Lolium multiflorum L.) from slurry N and from an equivalent amount of NH4 +-N in (15NH4) SO4 (control) was measured during 6 months of growth in pots. After this period the total recovery of labelled N in the top soil plus herbage was similar in the slurry and the control treatments. This indicated that gaseous losses from slurry NH4 +-N were insignificant. Consequently, the availability of slurry N to plants was mainly influenced by the mineralization-immobilization processes. The apparent utilization of slurry NH4 +-N mixed into soil was 7%, 14% and 24% lower than the utilization of (NH4)2SO4-N in a sand soil, a sandy loam soil and a loam soil, respectively. Thus, the net immobilization of N due to slurry application increased with increasing soil clay content, whereas the recovery in plants of 15N-labelled NH4 +-N from slurry was similar on the three soils. A parallel incubation experiment showed that the immobilization of slurry N occurred within the first week after slurry application. The incorporation of slurry N by simulated injection increased the plant uptake of both total and labelled N compared to mixing the slurry into the soil. The apparent utilization of injected slurry NH4 +-N was 7% higher, 8% lower and 4% higher than the utilization of (NH4)2SO4-N in the sand, the sandy loam and the loam soil, respectively. It is concluded that the spatial distribution of slurry in soil influenced the net mineralization of N to the same degree as did the soil type.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011466
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 60
    Digitale Medien
    Digitale Medien
    Effects of timing and supply of nitrogen on nitrogen remobilization from vegetative organs and redistribution to developing seeds of sunflower (1995)
    Springer
    Plant and soil 170 (1995), S. 359-370 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Helianthus annuus L. ; 15N ; nitrogen supply ; redistribution ; remobilization ; seed N ; sunflower ; total N ; vegetative organs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A glasshouse study was made of the distribution of 15N among vegetative organs of sunflower and its later remobilization and redistribution to seeds, as influenced by the developmental stage at which 15N was provided, and by the N status of the plants. Plants of Hysun 30 sunflower were grown in sand culture and provided with K15NO3 for a 3-day period at: (a) 3 days before the end of floret initiation; (b) 3 days before anthesis; (c) the start of anthesis; (d) full anthesis; and (e) 8 days after full anthesis. The plants were grown on a range of N supply rates, from severely deficient to more than adequate for maximum growth. Nitrogen-15 was distributed to all parts of the plant at the end of the 15N uptake periods. With the exception of the most N-stressed plants, subsequent remobilization of 15N from roots, stems and leaves occurred irrespective of the time the 15N was taken up. However, the percentage redistribution to seeds of 15N taken up at the end of floret initiation was less than for 15N taken up at anthesis. Remobilization of 15N from leaves and roots was higher (70%) for 15N taken up during and after anthesis than for 15N taken up at the end of floret initiation (45%), except for plants grown on the lowest N supply. By contrast, remobilization of 15N from the stem was lower for 15N taken up after full anthesis (40%) than before or during anthesis (〉70%). The proportion of 15N remobilized from the top third of the stem was less than that from the bottom third, and decreased with increasing plant N status. Nitrogen-15 taken up over the 3-day supply periods during anthesis contributed from 2 to 11% of the total seed N at maturity; the contribution to seeds was greatest for plants grown on the highest N supply. Nitrogen taken up just before and during anthesis contributed most of the N accumulated in mature seeds of plants grown on an adequate N supply, but N taken up between the end of floret initiation and just before anthesis, or after full anthesis seemed to make an equally important contribution to mature seeds as N taken up during anthesis for plants grown on a very low N supply. It was concluded that the development of florets and seeds of sunflower is supported by N taken up by the plant between the end of floret initiation and anthesis, and by N redistributed from vegetative organs. Unless soil N is so low as to impair early growth, split applications of N fertilizer would be best made just before the end of floret initiation (‘star stage’) and just before anthesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010490
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 61
    Digitale Medien
    Digitale Medien
    Mobilization of the reserve N in citrus (1995)
    Springer
    Plant and soil 173 (1995), S. 205-210 
    Details
    ISSN: 1573-5036
    Schlagwort(e): citrus ; N mobilization ; N translocation ; 15N ; reserves
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The mobilization of N from reserve organs (leaves, roots, branches and trunk) to developing new organs was studied at different moments of the growth cycle. Three-year-old Valencia Late orange trees (Citrus sinensis (L.) Osbeck) were grown individually outdoors in 150 L containers filled with siliceous sand. Trees were irrigated with a nutrient solution labelled with potassium nitrate with an enrichment of 4 atom 15N % excess during a complete growth cycle. At the following year, plants were irrigated with unlabelled nutrient solution, and harvested throughout the growth cycle (flowering, fruit set, second flush, third flush, and dormancy). Total N and 15N analyses were carried out in the different organs of the plants. The highest amounts of N were found in leaves and roots (33–42% and 30–38%, respectively). Distribution of 15N was similar to that obtained for total N (42 and 39% of total 15N in leaves and roots, respectively) as is expected after a long period of labelling. Old leaves were the main reserve organs, contributing a 40–50% of the total N exported. Roots and aerial woody tissues exported between 30–35% and 15–25% of total reserve N, respectively. N exported by old leaves was approximately 57% of the N accumulated during the preceding year, while roots translocated 40% and trunk plus branches 35%. More than 70% of N accumulated in new organs during spring came from N stored in old organs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011457
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 62
    Digitale Medien
    Digitale Medien
    Management of biological N2 fixation in alley cropping systems: Estimation and contribution to N balance (1995)
    Springer
    Plant and soil 174 (1995), S. 119-141 
    Details
    ISSN: 1573-5036
    Schlagwort(e): decomposition ; isotope dilution ; 15N ; mineralization ; nodulation ; N use efficiency ; residue management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Alley cropping is being widely tested in the tropics for its potential to sustain adequate food production with low agricultural inputs, while conserving the resource base. Fast growth and N yield of most trees used as hedgerows in alley cropping is due greatly to their ability to fix N2 symbiotically with Rhizobium. Measurements of biological N2 fixation (BNF) in alley cropping systems show that some tree species such as Leucaena leucocephala, Gliricidia sepium and Acacia mangium can derive between 100 and 300 kg N ha-1 yr−1 from atmospheric N2, while species such as Faidherbia albida and Acacia senegal might fix less than 20 kg N ha-1 yr-1. Other tree species such as Senna siamea and S. spectabilis are also used in alley cropping, although they do not nodulate and therefore do not fix N2. The long-term evaluation of the potential or actual amounts of N2 fixed in trees however, poses problems that are associated with their perennial nature and massive size, the great difficulty in obtaining representative samples and applying reliable methodologies for measuring N2 fixed. Strategies for obtaining representative samples (as against the whole tree or destructive plant sampling), the application of 15N procedures and the selection criteria for appropriate reference plants have been discussed. Little is known about the effect of environmental factors and management practices such as tree cutting or pruning and residue management on BNF and eventually their N contribution in alley cropping. Data using the 15N labelling techniques have indicated that up to 50% or more of the tree's N may be below ground after pruning. In this case, quantification of N2 fixed that disregards roots, nodules and crowns would result in serious errors and the amount of N2 fixed may be largely underestimated. Large quantities of N are harvested with hedgerow prunings (〉300 kg N ha-1 yr-1) but N contribution to crops is commonly in the range of 40–70 kg N ha-1 season. This represents about 30% of N applied as prunings; however, N recoveries as low as 5–10% have been reported. The low N recovery in maize (Zea mays) is partly caused by lack of synchronization between the hedgerow trees N release and the associated food crop N demand. The N not taken up by the associated crop can be immobilized in soil organic matter or assimilated by the hedgerow trees and thus remain in the system. This N can also be lost from the system through denitrification, volatilization or is leached beyond the rooting zone. Below ground contribution (from root turnover and nodule decay) to an associated food crop in alley cropping is estimated at about 25–102 kg N ha-1 season-1. Timing and severity of pruning may allow for some management of underground transfer of fixed N2 to associated crops. However many aspects of root dynamics in alley cropping systems are poorly understood. Current research projects based on 15N labelling techniques or 15N natural abundance measurements are outlined. These would lead to estimates of N2 fixation and N saving resulting from the management of N2 fixation in alley cropping systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00032244
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 63
    Digitale Medien
    Digitale Medien
    Grain legumes and green manures as pre-rice crops in Northeast Thailand (1995)
    Springer
    Plant and soil 177 (1995), S. 111-126 
    Details
    ISSN: 1573-5036
    Schlagwort(e): added nitrogen interactions ; Aeschynomene afraspera ; cowpea ; groundnut ; 15N ; nitrogen recovery ; Sesbania rostrata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two field experiments were conducted on farmers' fields in Northeast Thailand to examine the potential of several green manure and short-duration grain legume species as pre-rice green manures. The performance of species mixtures was also investigated. Experiments were conducted under rainfed conditions both with and without recommended applications of lime, P and K fertilizers. 15N-isotope methods were used to estimate N2-fixation in the legumes and N supplied by the legume residues to a following rice crop. When provided with lime, P and K fertilizer, all legumes grew well and fixed 65–85% of their N, amounting to 59–102 kg N ha-1 wihin 90 days. The short-duration groundnut and a mixed Sesbania rostrata and multi-purpose cowpea treatment produced over 4 tonnes ha-1 residue dry weight which contained 135–150 kg N ha-1. In addition groundnut yielded almost 2 tonnes ha-1 of grain, whilst the intercrop yielded 1 t ha-1 of fresh pods of MCP, only 35% less than the sole MCP which only produced 41 kg N ha-1 in its stover. Rice dry weight increases of over 50% were found after several of the legume treatments, and 15N-based estimates indicated up to 18 kg N ha-1 was directly supplied by the legume stover to the rice. Without fertilizer application residue yields of the S. rostrata + multi-purpose cowpea mixed crop were poor (580 kg ha-1) and N2-fixation contributed only 57% of the N accumulated (20 kg N ha-1 fixed). The application of P and K fertilizers was found to approximately double residue yields with the combined addition of lime more than doubling these yields again, resulting in 88% of the legume N derived from N2-fixation (84 kg N ha-1). The following rice recovered 9–17% of the added legume N and the yield response in rice reflected the differences in legume yield. Application of P,K and lime resulted in a fivefold increase in the amount of legume N recovered by rice, indicating the importance of alleviating nutrient deficiencies through fertilizer application if green manures are to be used successfully in Northeast Thailand.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010342
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 64
    Digitale Medien
    Digitale Medien
    Time-course of nitrogen fixation in two bambara groundnut (Vigna subterranea L. Verdc.) cultivars (1994)
    Springer
    Biology and fertility of soils 18 (1994), S. 231-236 
    Details
    ISSN: 1432-0789
    Schlagwort(e): A-value ; Bradyrhizobium ; Genotype ; Growth stage ; 15N ; Nitrogen fixation ; Nodulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract TheA-value method, involving the application of a higher15N rate to a reference non-N2-fixing plant, was used to assess the magnitude of N2 fixation in two bambara groundnut cultivars at four growth stages [vegetative, 0–47 days after planting (DAP); early pod-filling, 47–99 DAP; mid-pod-filling, 99–120 DAP; physiological maturity, 120–148 DAP). The cultivars were Ex-Ada, a bunchy type, and CS-88-11, a slightly spreading type. They were grown on a loamy sand. Uninoculated Ex-Ada and CS-88-11 were used as reference plants to measure the N2 fixed in the inoculated bambara groundnuts. In this greenhouse study, soil was the major source of N in bambara groundnuts during vegetative growth, and during this period it accounted for over 80% of the N accumulaed in the plants. However, N2 fixation became the major source of plant N during reproductive growth. There were significant differences between the two cultivars in the ability to fix N2, and at physiological maturity, almost 75% of the N in CS-88-11 was derived from the atmosphere compared to 55% in Ex-Ada. Also, the total N fixed in CS-88-11 at physiological maturity was almost double that in Ex-Ada. Our data indicate that the higher N2 fixation in CS-88-11 was due to two factors, a higher intensity of N2 fixation and a longer active period of N2 fixation. The results also suggest that bambara groundnut genotypes could be selected for higher N2 fixation in farining systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00647672
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 65
    Digitale Medien
    Digitale Medien
    Nitrogen utilization by lowland rice as affected by fertilization with urea and green manure (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 215-223 
    Details
    ISSN: 1573-0867
    Schlagwort(e): 15N ; residual N ; Sesbania ; urea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field studies were conducted during two consecutive wet seasons in flooded rice (Oryza sativa L.) to determine the effect of green manure on urea utilization in a rice-fallow-rice cropping sequence. Replicated plots were fertilized with 60 to 120 kg of urea N ha−1 in three split applications (50, 25 and 25%) with or without incorporation of dhaincha (Sesbania aculeata L.) (100 kg N ha−1). During the first crop only 31 to 44% of the urea added was used by the rice. Incorporatingin situ grown dhaincha (GM) into the soil at transplanting had little effect on urea utilization. Forty-four to 54% of the N added was not recovered in the soil, rice crop, or as nitrate leachate during the first cropping season. Incorporation of GM had no effect on fertilizer N recovery. Only about 2% of the urea N added to the first rice crop was taken up by the second rice crop and, as in the first crop, the GM had little effect on residual N, either in amount or utilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750468
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 66
    Digitale Medien
    Digitale Medien
    Fate of inorganic 15N in the profile of different coniferous forest soils (1994)
    Springer
    Biology and fertility of soils 17 (1994), S. 101-107 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Nutrient cycle ; Coniferous forest ; Soil properties ; 15N ; Acidification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The fate of inorganic 15N added to different coniferous forest soils was traced throughout the soil profile (0–25 cm) in a laboratory experiment under controlled conditions of temperature and water content. Six soils with different chemical climates were compared. The sequestration of labelled N was significantly explained by the clay content but the correlation was improved when C and N content were included. The level of acidification, even in soil with a fine texture, reduced the immobilization. For a similar N input, sandy soils with low C content or high acidification showed a reduced N storage capacity, so that N excess would be able to pollute the ground-water.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00337740
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 67
    Digitale Medien
    Digitale Medien
    Effect of extracellular-enzyme activities on solubilization rate of soil organic nitrogen (1994)
    Springer
    Biology and fertility of soils 17 (1994), S. 32-38 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Organic matter ; Extracellular enzymes ; Solubilization ; Mineral N ; Total soluble N ; 15N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In a sandy soil containing 15N-labeled active (soluble and easily degradable) and non-labelled passive (recalcitrant) fractions of soil organic matter, the rate of net N mineralization (solubilization) was determined during a 55-day incubation at 25°C, 63% water-holding capacity and different levels of soil extracellular-enzyme activities. The active fraction of soil N was labelled by preincubation (at 5°C and 74% water-holding capacity for 6 months) of soil amended with 15N-labeled plant material. Increases in the activity of extracellular-enzymes in soil were induced by the addition of glucose and KH2PO4 at the beginning of the incubation. The results show that the contents of total soluble N (NO 3 − −N+NH 4 + −N + soluble organic N) were significantly higher in glucose-amended soil compared to the unamended soil. The increases in soluble N in soil amended with 1 and 2 mg glucose g-1 dry soil corresponded to a mean rate of net solubilization of 7.9±1.4 and 18.8±0.7 nmol N g-1 dry soil day-1, respectively. The mean rate of net N solubilization (3.6±1.0 nmol N g-1 dry soil day-1) in unamended soil was significantly lower than those of glucose amended soils. The content of 15N in total soluble N in soil amended with 2 mg glucose, for example, was diluted from 3.11±0.08 atom% before the incubation to 2.77±0.03 atom% after 55 days. This indicates that 89% of soluble-N accumulated in soil by the end of the incubation originated from the active fraction of soil N and the rest, estimated at 11%, originated from the passive fraction. The activities of soluble and total proteases as well as the rate of N solubilization in the soil increased with the application of glucose. The activity of these extracellular enzymes was highly correlated with the rates of net N solubilization. Thus, increases in extracellular-enzyme activities in glucose-amended soils had a priming effect on the solubilization of 15N-labeled active and non-labeled passive fractions of soil organic N. It seems that the activity of extracellular-enzymes expressed in terms of total and soluble protease activities could be a rate-limiting factor in the processes of soil organic N solubilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00418669
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 68
    Digitale Medien
    Digitale Medien
    Bi-directional transfer of nitrogen between alfalfa and bromegrass: Short and long term evidence (1994)
    Springer
    Plant and soil 164 (1994), S. 77-86 
    Details
    ISSN: 1573-5036
    Schlagwort(e): alfalfa ; bi-directional N transfer ; bromegrass ; long-term N transfer ; short-term N transfer ; 15N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Transfer of N from legumes to associated non-legumes has been demonstrated under a wide range of conditions. Because legumes are able to derive their N requirements from N2 fixation, legumes can serve, through the transfer of N, as a source of N for accompanying non-legumes. Studies, therefore, are often limited to the transfer of N from the legume to the non-legume. However, legumes preferentially rely on available soil N as their source of N. To determine whether N can be transferred from a non-legume to a legume, two greenhouse experiments were conducted. In the short-term N-transfer experiment, a portion of the foliage of meadow bromegrass (Bromus riparius Rhem.) or alfalfa (Medicago sativa L.) was immersed in a highly labelled 15N-solution and following a 64 h incubation, the roots and leaves of the associated alfalfa and bromegrass were analyzed for 15N. In the long-term N transfer experiment, alfalfa and bromegrass were grown in an 15N-labelled nutrient solution and transplanted in pots with unlabelled bromegrass and alfalfa plants. Plants were harvested at 50 and 79 d after transplanting and analyzed for 15N content. Whether alfalfa or bromegrass were the donor plants in the short-term experiment, roots and leaves of all neighbouring alfalfa and bromegrass plants were enriched with 15N. Similarly, when alfalfa or bromegrass was labelled in the long-term experiment, the roots and shoots of neighbouring alfalfa and bromegrass plants became enriched with 15N. These two studies conclusively show that within a short period of time, N is transferred from both the N2-fixing legume to the associated non-legume and also from the non-legume to the N2-fixing legume. The occurrence of a bi-directional N transfer between N2-fixing and non-N2-fixing plants should be taken into consideration when the intensity of N cycling and the directional flow of N in pastures and natural ecosystems are investigated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010113
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 69
    Digitale Medien
    Digitale Medien
    The fate of spring applied fertilizer N during the autumn-winter period: comparison between winter-fallow and green manure cropped soil (1994)
    Springer
    Plant and soil 160 (1994), S. 201-213 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium nitrate ; green manure ; incorporation of plant material ; 15N ; N loss ; N mineralization ; NO emission ; oilseed rape ; organic N pool
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment was carried out at a pilot plot that was cropped with oilseed rape, and then left partly fallow and partly cropped with a green manure (mustard) during the autumn after harvest of the oilseed rape. The rape residues were incorporated in the soil. Methods used to quantify the N fluxes from harvest until sowing of the next crop were (1) 15N balance method, (2) total mineral N analysis and (3) NO emission measurements. Losses of spring applied fertilizer N were negligible in cropped plots and minimal in fallow plots during the following autumn-winter period. Most of the plant-N residues was retained by the organic N pool of the upper 30-cm soil layer. The green manure contributed slightly to soil available N at sowing of the next crop. However, the incorporation of plant material resulted in a nitrate flux that was at risk of leaching on the fallow plots, and on the green manure plots after incorporation of the green manure. This nitrate was largely derived from soil organic N, not from unused fertilizer applied in spring or from immobilized fertilizer. The NO emissions from the green manure plots were significantly higher than emissions from the fallow plots. The plants had a stimulating effect on the NO emission. A relationship between the NO emission and the soil nitrate concentration could not be established. No emissions were measured after green manure incorporation due to the low temperatures at the pilot plot. However, a greenhouse experiment showed an increased emission after incorporation. The NO emissions seemed to be related with the soil ammonium concentration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010146
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 70
    Digitale Medien
    Digitale Medien
    Transfer of nitrogen from damaged roots of white clover (Trifolium repens L.) to closely associated roots of intact perennial ryegrass (Lolium perenne L) (1994)
    Springer
    Plant and soil 166 (1994), S. 181-185 
    Details
    ISSN: 1573-5036
    Schlagwort(e): mobile N ; N transfer ; 15N ; root damage ; stored N ; white clover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract An experiment is described in which the magnitude of N transferred from damaged white clover roots to perennial ryegrass was determined, using 15N labelling of the grass plant. There was no effect on the growth and N-fixation of the clover plants after removing part of the root system. The 15N data suggested that N had been acquired by all grass plants, even in plants grown alone with no further N supplied after labelling. However, after quantifying the mobile and stored N pools of the grass plants it was evident that significant transfer of N from clover to grass only took place from damaged clover roots. Dilution of the atom% 15N in the roots of the grass plants grown alone, and in association with undamaged clover roots, was explained by remobilisation of N within the plant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008331
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 71
    Digitale Medien
    Digitale Medien
    Fertilization rates and clay fixed ammonium in two Quebec soils (1994)
    Springer
    Plant and soil 163 (1994), S. 103-109 
    Details
    ISSN: 1573-5036
    Schlagwort(e): soil mineralogy ; 15N ; clay fixed ammonium ; fertilizer rate ; fertilizer nitrogen recovery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Clay fixed NH4 + can provide a significant sink for fertilizer N, as well as a source of N for plant uptake. Knowledge or soil NH4 + fixing capacity and release for crops is necessary to develop long-term fertilizer programs. Field experiments with corn (Zea mays L.) were carried out to investigate soil NH4 + fixing capacity and subsequent release as influenced by fertilizer rates using 15N in a Ste. Rosalie clay (fine, mixed, frigid, Typic Humaquept) and a Chicot sandy clay loam (fine-loamy, mixed, frigid, Typic Hapludalf). With high N rates increased NH4 + fixation occurred only in the Ste. Rosalie soil. At the end of the first growing season, fertilizer N recovery as clay fixed NH4 + for high and normal rates of fertilizer in the Ste. Rosalie soil was 17.8% and 28.7%, respectively and the recovery for the high and normal rates in the Chicot soil was 4.6 and 10.5%, respectively. Significant amounts of clay fixed NH4 +-N were released in the soil profile in the second year after 15N application on the Chicot soil. Recently clay fixed fertilizer NH4 +N was released more rapidly than that of the native fixed NH4 +, from the surface layer of the Ste. Rosalie soil. The fertilizer fixed NH4 + seems to be in a more labile N pool than the native fixed NH4 +-N in the Chicot soil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00033946
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 72
    Digitale Medien
    Digitale Medien
    Solubilization of soil organic N by alkaline-hydrolysing N fertilizers (1994)
    Springer
    Nutrient cycling in agroecosystems 38 (1994), S. 131-139 
    Details
    ISSN: 1573-0867
    Schlagwort(e): aqua ammonia ; di-ammonium phosphate ; gamma-irradiated soil ; 15N ; organic matter solubility ; urea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Interactions between15N-labelled fertilizers applied at concentrations representative of the fertilizer microsite and the solubility of the nitrogenous component of soil organic matter were investigated in laboratory experiments. Soil organic N was solubilized in aγ-irradiated soil due to addition of NH3(aq), and the fertilizer-induced loss of unlabelled total N in the extracted soil (ΔTUs) increased with increasing N fertilizer concentration and soil pH. ΔTUs was linearly correlated with ammoniacal-N concentration and the pH of the fertilized soil within the range of 7.5-10 (r = 0.94). Total organic N in the soil extract (OTe) increased rapidly up to day 14 following addition of 2000 mg urea-N kg−1 soil, but was then stable up to day 28. OTe of a range of soils increased from between 5 and 148 to between 15 and 368 mg N kg−1 soil after application of 1045 mg NH3-N kg−1 soil. While up to 25% of the organic N was solubilized by the fertilizer in nine soils, the change in total organic N in the extracts (ΔOTe) of three soils was not significant. The highest ΔOTe of 399 mg N kg−1 soil (35.4% of soil organic N) was measured after application of 2000 mg NH3-N kg−1 soil. pH and ΔOTe decreased in the order of NH3(aq) 〉 urea 〉 di-ammonium phosphate 〉 ammonium sulphate at equivalent rates of N addition. A negative ΔOTe was measured following application of ammonium sulphate. ΔOTe was correlated with the pH of the fertilized soil but not ammoniacal-N concentration for different N fertilizer sources.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00748773
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 73
    Digitale Medien
    Digitale Medien
    The effect of root temperature on the induction of nitrate reductase activities and nitrogen uptake rates in arctic plant species (1994)
    Springer
    Plant and soil 159 (1994), S. 187-197 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium ; arctic plants ; nitrate reductase ; nitrogen uptake ; 15N ; root temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We investigated whether six arctic plant species have the potential to induce nitrate reductase (NR) activity when exposed to NO3 --nitrogen under controlled environment conditions, using an in vivo assay that uses the rate of NO2 --accumulation to estimate potential NR activity. We also assessed the effect of low root temperatures on NR activity, growth and nitrogen uptake (using 15N applications) in two of the selected species. Five of the six species (Cerastium alpinum, Dryas intergrifolia, Oxyria digyna, Saxifraga cernua and Salix arctica) were capable of inducing NR activity when exposed to solutions containing 0.5 mM NO3 - at 20°C for 10 days. Although in vivo NR activity was not induced in Saxifraga oppositifolia under controlled conditions, we conclude that it was capable of growing successfully on NO3 -, due to the presence of moderate rates of NR activity observed in both NH4 +-grown and NO3 --treated plants. Exposure of O. digyna and D. integrifolia to 3°C root temperatures for two weeks, with the shoots kept at 20°C, resulted in root and leaf NR activity rates of NO3 --treated plants being reduced to rates exhibited by NH4 +-grown plants. Although these decreases in NR in both species appeared to be due to limitations in NO3 --uptake and growth rate (rather than direct low-temperature inhibition of NR synthesis per se), direct low-temperature inhibition of root NR synthesis could not be ruled out. In contrast to the temperature insensitivity of NH4 + uptake in D. integrifolia, NO3 --uptake in D. integrifolia was inhibited by low root temperatures. We conclude that the selected arctic species have the genetic potential to utilize NO3 --nitrogen, and that low root temperatures, in conjunction with other environmental limitations, may be responsible for the lack of induction of NR in D. integrifolia and Salix arctica under field conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009280
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 74
    Digitale Medien
    Digitale Medien
    Hyphal N transport by a vesicular-arbuscular mycorrhizal fungus associated with cucumber grown at three nitrogen levels (1994)
    Springer
    Plant and soil 160 (1994), S. 1-9 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 15N ; Cucumis sativus ; Glomus intraradices ; hyphal N transport ; plant N status ; VA mycorrhiza
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Cucumis sativus L. cv. Aminex (F1 hybrid) was grown alone or in symbiosis with Glomus intraradices Schenck and Smith in containers with two hyphal compartments (HCA and HCB) on either side of a root compartment (RC) separated by fine nylon mesh. Plants received a total of either 100, 200 or 400 mg N which were applied gradually to the RC during the experiment. 15N was supplied to HCA 42 d after plating, at 50 mg 15NH4 +-N kg−1 soil. Lateral movement of the applied 15N towards the roots was minimized by using a nitrification inhibitor and a hyphal buffer compartment. Non-mycorrhizal controls contained only traces of 15N after a 27 d labelling period irrespective of the amount of N supplied to the RC. In contrast, 49, 48 and 27% of the applied 15N was recovered in mycorrhizal plants supplied with 100, 200 and 400 mg N, respectively. The plant dry weight was increased by mycorrhizal colonization at all three levels of N supply, but this effect was strongest in plants of low N status. The results indicated that this increase was due partly to the improved inflow of N via the external hyphae. Root colonization by G. intraradices was unaffected by the amount of N supplied to the RC, while hyphal length increased in HCA compared to HCB. Although a considerable 15N content was detected in mycorrhizal roots adjacent to HCB, only insignificant amounts of 15N were found in the external hyphae in HCB. The external hyphae depleted the soil of inorganic N in both HCA and HCB, while the concentration of soil mineral N was still high in non-mycorrhizal containers at harvest. An exception was plants supplied with 400 mg N, where some inorganic N was present at 5 cm distance from the RC in HCA. The possibility of a regulation mechanism for hyphal transport of N is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00150340
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 75
    Digitale Medien
    Digitale Medien
    Urea N uptake efficiency of ryegrass (Lolium perenne L.) in the presence of urease inhibitors (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 225-228 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Urease inhibitors ; Urea N efficiency ; 15N ; Ryegrass ; Hydroquinone (HQ) ; Phenyl phosphorodiamidate (PPDA) ; N-(n-butyl) phosphorothioic triamide (NBPT)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A greenhouse experiment was conducted to study the comparative efficiency of urea as an N fertilizer with and without the addition of different urease inhibitors. Ryegrass (Lolium perenne L.) was used as the test plant and the N balance technique with 15N was applied. Three urease inhibitors, hydroquinone, phenyl phosphorodiamidate (PPDA), and N-(n-butyl) phosphorothioic triamide (NBPT), were evaluated for their effects on urea-N uptake as well as on grass yield. The addition of urease inhibitors, except for hydroquinone in the later growth period, did not significantly influence the dry matter weight. Throughout the whole growth period, only NBPT significantly increased the total urea-N uptake. In the uninhibited system, the major fertilizer N loss occurred during the first period of grass growth, presumably via NH3 volatilization, since the environment did not favour the other pathways of N loss. However, an appreciable amount of urea N was lost during the later growth period in all inhibited systems, especially in the hydroquinone-treated system. This indicates that the application of urease inhibitors could not eliminate the urea N loss. The greater N loss in the hydroquinone-treated soil appears to be related to the inhibition by hydroquinone of nitrification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00361616
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 76
    Digitale Medien
    Digitale Medien
    Effect of nitrogen application on the A N value of soil (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 299-301 
    Details
    ISSN: 1432-0789
    Schlagwort(e): A N value ; 15N ; Nitrogen fixation ; Glycine max ; Hordeum vulgare
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Pot experiments were conducted with two soils, from Rottenhaus and Seibersdorf in Austria, to ascertain whether the rate of fertilizer N application and the test crop would influence the amount of N available in the soil as assessed by the A-value method. 15N-labelled fertilizer was applied at rates of 10, 25, 40, 60, and 100 mg N kg-1 soil, corresponding approximately to 20, 50, 80, 120 and 200 kg N ha-1 respectively, and two crop species, barley (Hordeum vulgareL.) and non-nodulating soybean (Glycine max L.) were used to determine the soil A N value under the various fertilizer regimes. The results showed that the Rottenhaus soil had a higher A N value than the Seibersdorf soil, suggesting that the former was more fertile than the latter. The A N values of both soils were significantly affected by the level of N application. When grown in the same soil, the two test crops showed significantly different fertilizer use efficiency and per cent N derived from fertilizer when the rate of N application exceeded 20 kg ha-1. Thus, the A N value as determined by the two test crops differed significantly for the same soil when the rate of N application was greater than 20 kg/ha. The difference was greater when the soil fertility level was high. The dependence of the A N value on the level of N application and the species of crop seriously compromises the suitability of this method for determining plant-associated N2 fixation. Hence, considerable caution is required when using this method to estimate plant-associated N2 fixation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00369309
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 77
    Digitale Medien
    Digitale Medien
    N supply by groundnuts to maize in a maize plus groundnut intercropping system, as affected by the genotype (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 215-219 
    Details
    ISSN: 1432-0789
    Schlagwort(e): N2 fixation ; N-supplying ability ; 15N ; Arachis hypogaea ; Intercropping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Identification of legume genotypes with high N-supplying ability is important in improving and sustaining the productivity of low-input cropping systems. Hence, 15N-aided studies were made to ascertain the relative N-supplying ability of some cultivars of groundnut, a widely grown tropical legume. The study was conducted outdoors in 1991 at Kamburupitiya, Sri Lanka, in tanks filled with 64 kg soil which had been tagged by incorporating 15N-labelled plant material. Maize cv. Badra was grown as a monocrop and as an intercrop with five genotypes of groundnut, X-14, MI-1, Red Spanish, ICGV 87127, and a non-nodulating line. All the nodulating genotypes derived over 90% of their N from the atmosphere. Significant genotypic differences in N2 fixation were observed. X-14 fixed the highest amount (1.95 g plant-1), while Red Spanish the lowest (0.88 g plant-1). Intercropping of maize with nodulating groundnut significantly decreased the 15N atom excess of maize, depending on the genotype. However, this decrease did not appear to be related to the amount of N2 fixed, based on aboveground material. The per cent N derived by maize from the intercropped groundnuts varied from 17% (X-14) to 39% (Red Spanish), indicating a marked genotypic variability in N-suppling ability. X-14, which fixed the largest amounts of N2, grew most vigorously compared to other genotypes, causing a growth depression in the maize. The genotype that fixes the most N2 may therefore not necessarily have the greatest N-supplying ability. The transfer of N from the legume and the consequent improvement of N nutrition in the associated cereal in low-fertility situations is therefore expected to be high when the growth of the legume is intermediate and does not suppress the growth of the cereal.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00361614
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 78
    Digitale Medien
    Digitale Medien
    The release and plant uptake of nitrogen from some plant and animal manures (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 285-293 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Manures ; N mineralisation ; N uptake ; 15N ; Added nitrogen interactions ; Priming effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Field and laboratory experiments were used to examine the efficiency of N uptake from various manure forms, and at different rates of application. In a field experiment, wheat was grown on soils with different amounts of 15N-labelled legume residues. The amount of N taken up by the crop was directly proportional to the amount applied, with a recovery of between 15% and 23% of the legume N. In a second field experiment, inorganic N was applied at rates varying from 0 to 120 kg N ha-1 in the presence and absence of poultry manure. The uptake of N by barley was 11 kg ha-1 greater in the manured plots when no inorganic N was applied, and 23 kg ha-1 greater when N was applied at the top rate. N uptake in a pot experiment was again shown to be directly proportional to the rate of manure application, but the amount of N taken up was strongly related to the N content of the manure. An incubation experiment demonstrated that net N mineralisation reached a maximum where residue concentrations were 1,5%. The significance of added nitrogen interactions in the context of manure-N additions is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00337214
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 79
    Digitale Medien
    Digitale Medien
    Ontogenic variation in nitrogen fixation and accumulation of nitrogen in mungbean, blackgram, cowpea, and groundnut (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 125-130 
    Details
    ISSN: 1432-0789
    Schlagwort(e): N2 fixation ; Ontogeny ; 15N ; Vigna radiata ; Vigna mungo ; Vigna unguiculata ; Arachis hypogaea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ontogenic variations in N2 fixation and accumulation of N by the mungbean (Vigna radiata L. Wilczek), blackgram (Vigna mungo L. Hepper), cowpea (Vigna unguiculata L. Walp.), and groundnut (Arachis hypogaea L.) were studied by a 15N-dilution technique. Pots filled with 7 kg of red yellow podzolic soil were used. Samples were taken 20, 40, 60, and 80 days after emergence which approximately corresponded to preflowering, flowering, early/mid-pod filling and late pod filling stages, respectively. During early growth (up to 40 days after emergence), the carryover of seed N accounted for a considerable fraction of the total plant N in the legumes, the highest being in the groundnut. With a correction for carryover, the groundnut derived over 45% of its N content from the atmosphere 20 days after emergence whereas the corresponding figures were 33% for the blackgram and about 28% for the cowpea and mungbean. Between flowering and early pod fill, there was a rapid increase in N2 fixation in all legumes except in groundnut which showed highest fixation from 60 to 80 days after emergence. In the mungbean, N2 fixation and uptake of soil N were insignificant 60 days after emergence while in other legumes these processes continued beyond this time. All legumes derived about 90% of their N from atmosphere by 80 days after emergence. However, due to considerable interspecific differences in total N yield the final amount of N2 fixed showed an appreciable variation among legumes. It was highest in the groundnut (443 mg N plant-1) followed by the cowpea (385), blackgram (273), and mungbean (145), respectively. The groundnut maintained nodules until the late pod filling stage while in other legumes, nodules senesced progressively following the mid-pod filling stage. During pod filling there was a net mobilization of N from vegetative tissues to developing pods in the mungbean, which amounted to about 20% of N in seeds. This mobilization was not evident in other legumes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00369413
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 80
    Digitale Medien
    Digitale Medien
    15N Abundance of forests is correlated with losses of nitrogen (1993)
    Springer
    Plant and soil 157 (1993), S. 147-150 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 15N ; forest soils ; N deposition ; N losses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A direct correlation was found between fractional losses of added N and the change in δ 15N‰ during 19 years in an experiment with annual additions of N at three rates to a Scots pine (Pinus sylvestris L.) forest in northern Sweden. This confirms that processes leading to losses of N discriminate against 15N, and opens possibilities to conduct retrospective studies of the N balance in forests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00038758
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 81
    Digitale Medien
    Digitale Medien
    15N Abundance of forests is correlated with losses of nitrogen (1993)
    Springer
    Plant and soil 157 (1993), S. 147-150 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 15N ; forest soils ; N deposition ; N losses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A direct correlation was found between fractional losses of added N and the change in δ15N‰ during 19 years in an experiment with annual additions of N at three rates to a Scots pine (Pinus sylvestris L.) forest in northern Sweden. This confirms that processes leading to losses of N discriminate against15N, and opens possibilities to conduct retrospective studies of the N balance in forests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02390237
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 82
    Digitale Medien
    Digitale Medien
    Variation in 15N enrichment of crimson clover labeled under field conditions (1993)
    Springer
    Plant and soil 152 (1993), S. 255-260 
    Details
    ISSN: 1573-5036
    Schlagwort(e): crimson clover ; field labeling ; legume ; nitrogen ; 15N ; variability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Plant material labeled with 15N is often used to determine recovery of N from green manure crops by subsequent crops. In this study, 15N enriched crimson clover (Trifolium incarnatum L.) was grown at a field site where it was to be utilized in a subsequent experiment. A foliar spray of (NH4)2SO4 (99 atom % excess 15N) was applied to a 1.2 m × 8.8 m plot of crimson clover at a rate of 10 kg N ha−1 in early March 1990, immediately prior to the period of rapid vegetative growth. Clover shoots harvested in April contained 1.72 atom % excess 15N. Total N concentration of enriched clover was similar to that in adjacent untreated clover. Clover shoots contained 20% of the applied 15N, and an additional 27% was recovered from the surface soil horizon (0 to 15 cm). A gradient was observed across the plot, with clover enrichment increasing from 1.3 to 2.2 atom % excess 15N. Recovery of applied 15N in soil was highest in the subplots with lowest clover enrichment. Variability in 15N enrichment was also observed among plant parts: leaves from the basal half of shoots had 2.2 atom % excess 15N; while leaves from the terminal half of shoots, terminal stems, and basal stems had between 1.1 and 1.4 atom % excess 15N.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00029095
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 83
    Digitale Medien
    Digitale Medien
    Nitrogen uptake in needles of Scots pine (Pinus sylvestris L.) when exposed to gaseous ammonia and ammonium fertilizer in the soil (1993)
    Springer
    Plant and soil 153 (1993), S. 231-242 
    Details
    ISSN: 1573-5036
    Schlagwort(e): air pollution ; ammonia ; ammonium ; 15N ; N concentration ; needle ; pine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Young saplings of Pinus sylvestris L. were exposed to gaseous NH3 at 53 or 105 μg m−3 for one year in open-top chambers. Saplings received 15N-labelled (NH4)2SO4 via the soil. To examine the importance of foliar N uptake, changes in the concentration of total and labelled N in the needles were followed. Increase in needle biomass and N concentration were found in trees exposed to NH3, confirming that atmospheric NH3 acted as a N fertilizer. NH3 had a greater and quicker effect than (NH4)2SO4: compared with the growth in ambient air, the N concentration in the needles exposed to NH3 had increased by 49% in four months, while the increase after highest N-fertilization (200 kg N ha−1 y−1) was only 8%. The small contribution of NH4 + fertilization to the total N concentration was not due to a deficient N uptake: the 15N concentration in the needles increased significantly with time. On the other hand, NH3 uptake in shoots may have a negative effect on the NH4 + root uptake. The relation between plant N and atmospheric NH3 concentration was non-linear and possible reasons for this observation are discussed. Fumigation with NH3 significantly decreased the ratios of K/N and P/N, showing that fumigation disrupted the nutrient balance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00012996
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 84
    Digitale Medien
    Digitale Medien
    Nitrous oxide and dinitrogen emissions from urine-affected soil under controlled conditions (1993)
    Springer
    Plant and soil 151 (1993), S. 127-138 
    Details
    ISSN: 1573-5036
    Schlagwort(e): urine ; nitrous oxide ; dinitrogen ; nitrification ; denitrification ; carbon ; 15N ; nitrification inhibitor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A 15N labelling technique was used to measure N2O and N2 emissions from an undisturbed grassland soil treated with cow urine and held at 30 cm water tension and 20°C in a laboratory. Large emissions of dinitrogen were detected immediately following urine application to pasture. These coincided with a rapid and large increase in soil water-soluble carbon levels, some of this increase being attributed to solubilization of soil organic matter by high pH and ammonia concentrations. Emissions of nitrous oxide generally increased with time in contrast to dinitrogen fluxes which decreased as time progressed. Estimated losses of N2O and N2 over a 30 day period were between 1 to 5% and 30 to 65% of the urine N applied plus N mineralized from soil organic matter, respectively. Most of the N2 and N2O originated from denitrification with nitrification-denitrification being of minor significance as a source of N2O. Comparisons of the 15N enrichments in the soil mineral N pools and the evolved N2O suggested that much of the N2O was produced in the 5–8 cm zone of the soil. It is concluded that established grassland soils contain large amounts of readily-oxidizable organic carbon which may be used by soil denitrifying organisms when nitrate is non-limiting and soil redox potential is lowered due to high rates of biological activity and high soil moisture contents. ei]{gnR}{fnMerckx}
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010793
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 85
    Digitale Medien
    Digitale Medien
    Differences in uptake kinetics of ammonium and nitrate in legumes and cereals (1993)
    Springer
    Plant and soil 154 (1993), S. 67-72 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium uptake ; cereals ; kinetics ; legumes ; 15N ; nitrate uptake ; translocation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Influx isotherms were obtained for nitrate and ammonium from three legumes, Cajanus cajan (L.) Millsp., Cicer arietinum L. and Arachis hypogaea L. and three cereals, Sorghum bicolor (L.) Moench., Pennisetum glaucum L. and Zea mays L. The transition in influx isotherms for both nitrogen sources was found to be within the concentration range (0.05–2.5 mM) tested. There were significant differences in Km and Vmax for ammonium between legumes and cereals. The difference in the kinetic properties for nitrate uptake between the two groups of plants only became apparent at the higher concentration tested. Legumes translocated absorbed nitrate and ammonium to shoots more rapidly than cereals. Results show that there are significant differences in uptake and translocation of ammonium and nitrate between legumes and cereals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011073
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 86
    Digitale Medien
    Digitale Medien
    The course of 15N-ammonium nitrate in a spring barley cropping system (1993)
    Springer
    Plant and soil 150 (1993), S. 167-175 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium nitrate ; barley ; fertilizer efficiency ; 15N field experiment ; N recovery ; 15N ; plant uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract 15N-labelled ammonium nitrate was applied to spring barley growing on a Cambisol soil in western Switzerland. Immobilization, plant uptake and disappearance of inorganic nitrogen were followed at frequent intervals. Fertilizer nitrogen disappeared shortly after its application, mainly through immobilization by soil microorganisms and absorption by the crop. Some of the added nitrogen was probably denitrified as a result of humid conditions during the first days after fertilizer application. At the end of the growing season, 31% of the added nitrogen was recovered from the aerial barley plants, and 56% was immobilized by microorganisms. Most of the fertilizer nitrogen not used by the crop was immobilized in the upper 0–30 cm soil layer. This prevented downward movement of nitrate and limited nitrogen losses. Fertilizer efficiency was mainly determined by the competition between crop uptake and microbial immobilization. Careful consideration of the time of fertilization, taking into account plant growth and weather conditions, can result in an increase in fertilizer efficiency and minimal pollution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00013014
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 87
    Digitale Medien
    Digitale Medien
    A comparison of the effects of subsoiling on plant uptake and leaching losses of sulphur and nitrogen from a simulated urine patch (1993)
    Springer
    Plant and soil 155-156 (1993), S. 375-378 
    Details
    ISSN: 1573-5036
    Schlagwort(e): clover ; grass ; leaching ; lysimeter ; nitrogen ; 15N ; nutrient balances ; nutrient uptake ; pasture ; subsoiling ; sulphur ; 35S
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Synthetic cow urine labelled with 35S and 15N was applied to large, undisturbed, monolith lysimeters sampled from subsoiled and non-subsoiled areas of a grass/clover pasture. For one year following the urine application, the lysimeters were subjected to a combination of natural rainfall, simulated rainfall and simulated flood irrigations. Drainage from the lysimeters was sampled regularly and monthly (approx.) pasture cuts taken. At the end of the year, the lysimeters were destructively sampled in 50 mm depth increments for soil analysis. Leachates, plant samples and soil samples were analysed for 35S and 15N. There were no significant differences in plant uptake of 35S and 15N between the subsoiled and nonsubsoiled lysimeters. Initially grass showed a higher degree of labelling than clover. Total amounts of 35S and 15N leached from the subsoiled lysimeters were approximately twice that leached from the nonsubsoiled ones. Leaching patterns differed substantially between the two nutrients. Total recoveries of 35S (in plants, leachates and soil extracts) accounted for 82% of the applied 35S for the subsoiled lysimeters and 72% for non-subsoiled ones. The unrecovered 35S is considered to have been incorporated into soil organic matter. Total recoveries of 15N (in plants, soil and leachates) were similar to those for 35S, but unrecovered 15N is attributed to loss by denitrification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025061
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 88
    Digitale Medien
    Digitale Medien
    Fate of nitrogen fertilizer applied on two main arables crops, winter wheat (Triticum aestivum) and sugar beet (Beta vulgaris) in the loam region of Belgium (1993)
    Springer
    Plant and soil 155-156 (1993), S. 367-370 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Broadcast ; loam soil ; 15N ; N losses ; N recovery ; row application ; split dressing ; sugar beet ; winter wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Since 1986, the fate of fertilizer N (NH4NO3 or NaNO3) applied in field conditions on two main arable crops, winter wheat (Triticum aestivum) and sugar beet (Beta vulgaris), has been studied using 15N. Up to a rate of 200 kg ha-1 of N, mean recovery of fertilizer by winter wheat was 70%, provided it had been split applied. Single application (with or without dicyandiamid) was less effective. For sugar beet, in 1990, 1991 and 1992, 40% of fertilizer N was found in the crop at harvest when NH4NO3 had been broadcast at 100 to 160 kg N ha-1 at sowing time. For the same N rate, recovery was 50% when row applied near the seeds and 60% for 80 kg N ha-1. For the two experimental crops, residual fertilizer N in soil was exclusively organic. It ranged from 15 to 30% of applied N and was located in the 30 cm upper layer. Losses were generally lower with winter wheat (12%) than with sugar beet (20–40%) and could be ascribed to volatilization and denitrification. Soil derived N taken up by the plant was site and year dependent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025059
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 89
    Digitale Medien
    Digitale Medien
    Nitrogen use efficiency of rice reconsidered: What are the key constraints? (1993)
    Springer
    Plant and soil 155-156 (1993), S. 359-362 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 15N ; microbial biomass ; nitrogen uptake efficiency ; Oryza sativa ; soil nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Recent field studies on irrigated rice at the IRRI research farm indicate efficient use of fertilizer-N based on plant uptake of applied N, (estimated by N difference), and utilization of acquired N for increased grain yield. These findings contrast with 15N uptake in microplot studies which underestimate the actual increase in plant N from added fertiliser. Constraints other than uptake efficiency, however, may govern fertiliser-N efficiency in farmers fields. In a study of 44 farmers' fields in Central Luzon, rice yields ranged from 2.5 to 6.2 t ha-1 and N uptake from 35 to 95 kg N ha-1 in plots without fertiliser-N addition. Farmers applied from 35 to 240 kg N ha-1, but there was no relationship between the N rate used by each farmer and the effective soil N supply. Mean N uptake efficiency from fertiliser by N difference was only 36%. We conclude that improved fertiliser-N efficiency by farmers will require a more information-intensive management strategy that makes N fertiliser inputs better fitted to the seasonal pattern of crop N demand and soil N supply.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025057
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 90
    Digitale Medien
    Digitale Medien
    Leaching loss of calcium, magnesium, potassium and nitrate derived from soil, lime and fertilizers as influenced by urea applied to undisturbed lysimeters in south-east Nigeria (1992)
    Springer
    Nutrient cycling in agroecosystems 31 (1992), S. 281-289 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Leaching ; calcium ; magnesium ; potassium ; nitrate ; tropical soils ; 15N ; urea ; shifting cultivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Calcium hydroxide was applied to monolith lysimeters at Onne in south-east Nigeria. Eight lysimeters were cropped with maize followed by upland rice and four were uncropped. The cropped and two uncropped lysimeters received Mg, K and urea in the first season. Two uncropped lysimeters received no fertilizers. Drainage water was collected during the two growing seasons and analyzed for calcium, magnesium, potassium, sodium, nitrate and chloride. The fertilizer applied in the second season was not leached during the year of application. The cropped lysimeters lost 27 percent of the sum of the exchangeable Ca in the soil profile and the calcium added, and 29 percent of the corresponding sum for Mg. With no crop, the losses increased to 34 and 37 percent, respectively, but with no crop or fertilizer, the losses were similar to those from the cropped lysimeters. The loss of potassium ranged from 6 percent from the unfertilized lysimeters to 10 percent in the cropped lysimeters. The amounts of sodium leached ranged from 29 to 35 kg Na ha−1. The bulk of the calcium and magnesium leached from calcium hydroxide and fertilizers occurred in the second season when the loss was in good agreement with the amount of nitrate lost giving (Ca + Mg)/NO3 charge ratios of approximately one. Urea increased the amount of nitrate leached and led to a corresponding increase in the amounts of calcium and magnesium lost in the drainage water. The charge ratio remained unchanged when the cations were leached only with nitrate derived from the mineralization of soil organic matter. In the cropped lysimeters, this source accounted for about four times more nitrate in the drainage water than the fertilizer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01051280
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 91
    Digitale Medien
    Digitale Medien
    Influence of delaying flood and preflood nitrogen application on dry-seeded rice (1992)
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 55-59 
    Details
    ISSN: 1573-0867
    Schlagwort(e): 15N ; nitrogen ; rice ; soil N ; N fertilizer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In the southern U.S. rice belt it is recommended that rice (Oryza sativa L.) grown in the dry-seeded, delayed flood cultural system have the preflood N fertilizer applied and the field flooded at the fourth to fifth leaf stage of plant development. The objective of this field study was to determine if delaying the flood and preflood N application past the fifth leaf stage was detrimental to rice total N and fertilizer15N uptake, total dry matter, and grain yield. This study was conducted on a Crowley silt loam (Typic Albaqualfs) and a Perry clay (Vertic Haplaquepts). The preflood N fertilizer and flood were delayed 0, 7, 14, or 21 d past the fourth to fifth leaf stage, after which time a permanent flood was established and maintained until maturity. All treatments received 20.5 g N m−2 as15N-labeled urea in three topdress applications. All plant and soil samples were taken at maturity. Harvest index increased as the preflood N and flood were delayed past the 4 to 5 leaf stage. Total N in the grain + straw either decreased or showed a decreasing trend as the N and flood were delayed. Similarly, uptake of native soil N decreased as flood was delayed. Conversely, percent recovery of fertilizer N in the rice plant and the plant-soil system increased as the preflood N and flood were delayed. Rice grain yield was not significantly affected by delaying the preflood N and flood up to 21 d.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01054394
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 92
    Digitale Medien
    Digitale Medien
    Fate of nitrogen (15N) from oxamide and urea applied to turf grass: A lysimeter study (1992)
    Springer
    Nutrient cycling in agroecosystems 33 (1992), S. 71-79 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Nitrogen balance ; 15N ; oxamide ; slow release fertilizer ; soil microbial biomass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Slow release N fertilizers are receiving increasing attention for use on turf grass, but their fate in the plant-soil system is still poorly understood. We aimed to quantify the uptake and recovery of N by a mixture of grasses when applied as either urea or oxamide in different diameter granules using a tracer technique (15N). The effects of the N source on soil biomass, root density and amount of readily available organic C in soil were also evaluated. In a first experiment oxamide in 4–5 mm diameter granules was compared with urea. The initial N absorption, 40 days after fertilization (d.a.f.), was higher for urea (23.5%) than for oxamide (12.1%), but after 64 days absorption efficiencies were about the same (11%) for both fertilizers. Fertilizer-derived N lost by leaching was much greater from the urea-fertilized soil (1.57 g), compared with losses from oxamide-fertilized soil (0.05 g). The total residual fertilizer N remaining in the system at the end of the experiment was 26.7% of applied urea N and 39.6% of applied oxamide N. Cumulated absorption efficiencies, calculated after dismantling the lysimeters, were 43.1% for urea and 54.8% for oxamide (roots included). A priming effect caused by a larger uptake of soil N because of the better root development was found in the oxamide-treated lysimeter. Fertilization with oxamide also caused an increase in the amount of soil microbial biomass. In a second experiment, the efficiencies and fertilizer N uptake rates from oxamide applied at two different granule sizes (1–2 mm and 5–10 mm) were evaluated. The amount of soil N taken up by the grass was linearly related to root density (r = 0.92).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01058011
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 93
    Digitale Medien
    Digitale Medien
    Effects of litter quality and microarthropods on N dynamics and retention of exogenous 15N in decomposing litter (1992)
    Springer
    Biology and fertility of soils 12 (1992), S. 241-252 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Decomposition ; Litter ; Microarthropods ; Nitrogen ; 15N ; Litterbags ; Cornus florida ; Quercus prinus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Surface additions of (15NH4)2SO4 were used to measure the immobilization and subsequent movement of exogenous N added to two litter types of contrasting quality (Cornus florida and Quercus prinus). Litterbaskets were used to measure the litter mass loss and N dynamics and to follow the movement of the 15N label through litter, F layer, and soil pools. Half of the litterbaskets of each species were treated with naphthalene to reduce microarthropod densities. The faster decomposing C. florida litter maintained a higher excess atom % 15N, and a greater relative concentration of the labeled input (μg 15N g−1) than did Q. prinus litter. In both litter types the excess atom % 15N, relative concentration (μg 15N g−1), and absolute amount of label recovered in the litter declined over time. This occurred during a period of net accumulation of total litter N, implying simultaneous release of the initial input and immobilization of N from other sources. The concentration of 15N in the soil increased over time, while the F layer apparently acted as an intermediary in the transfer of 15N from litter to soil. Naphthalene effectively reduced microarthropod numbers in all horizons of the litterbaskets and significantly reduced the decay rates of Q. prinus, but not C. florida litter. Naphthalene did not appear to affect total N dynamics in the litter. However, with all horizons taken together, the naphthalene-treated litterbaskets retained more total 15N than the control litterbaskets. Naphthalene also changed the vertical distribution of 15N within litterbaskets, so that the litter retained less of the 15N-labeled input and the F layer and soil horizons retained more of the labeled input than in control litterbaskets. Our major conclusions are: (1) the N pool of decomposing litter is dynamic, with simultaneous N release and immobilization activating N turnover even during the net accumulation phase; (2) litter quality is an important determinant of immobilization and retention of exogenous N inputs and, therefore, turnover of the litter N pool; and (3) microarthropod activity can significantly affect the incorporation and retention of exogenous N inputs in decomposing litter, although these changes are apparently not reflected in net N accumulation or release during the 1st year of decomposition. However, the naphthalene may have affected microbially mediated N dynamics and this possibility needs to be considered in interpreting the results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336039
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 94
    Digitale Medien
    Digitale Medien
    Influence of temperature on mineralization kinetics with a nitrification inhibitor (mixture of dicyandiamide and ammonium thiosulphate) (1992)
    Springer
    Biology and fertility of soils 13 (1992), S. 1-5 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Nitrification inhibitor ; Dicyandiamide ; 15N ; Incubation ; Temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The influence of temperature on the action of a dicyandiamide nitrification inhibitor was studied during a laboratory incubation after the addition of ammonium sulphate labelled with 15N. In the control treatment, nitrification was only slightly affected by temperature and was rapid; on the 42nd day, two-thirds of the 15N was incorporated into the nitrate fraction while no further tracer was found in ammoniacal form. With the addition of dicyandiamide, the process was slowed down considerably when the temperature was maintained at 10°C, and only about 10% of the 15N was nitrified in 6 months. After 1 month of incubation at 10°C, a temperature increase to 15°C for 4 weeks modified the nitrification kinetics only slightly. However, as soon as the temperature reached 20°C, the beginning of dicyandiamide decomposition and an increase in the quantity of NO 3 - -N was observed. The inhibition was measured by the nitrification index, which was greater than 80% as long as the temperature did not exceed 15°C, and decreased to 10% after 6 months; this value was reached only after 1 year in soil maintained at 10°C. The half-life of the NH 4 + was decreased by raising the temperature. In the experimental conditions described, nitrification was inhibited by the dicyandiamide for at least 6 months provided the temperature did not exceed 15°C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00337229
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 95
    Digitale Medien
    Digitale Medien
    Nitrogen fixation efficiency, interspecies N transfer, and root growth in barley-field pea intercrop on a Black Chernozemic soil (1992)
    Springer
    Biology and fertility of soils 13 (1992), S. 11-16 
    Details
    ISSN: 1432-0789
    Schlagwort(e): Typic cryoboroll ; N yield ; 15N ; Root length ; Grass-legume intercrop ; Nitrogen fixation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Barley-field pea intercrops have been shown to increase N yield when grown under cryoboreal subhumid conditions. In this study, we extended previous research by testing the hypotheses that (1) the intercropped field pea fixes a greater proportion of its shoot and root N than does sole-cropped field pea; (2) N is transferred from the annual legume to the cereal during the growing season; and (3) root production is greater under intercropped than sole-cropped conditions. Unconfined microplots seeded to barley, field peas, or a barley-field pea intercrop were fertilized with N at 10 kg ha-1 as (NH4)2SO4 (5.21 atom % 15N excess). Both the intercropped and sole-cropped barley derived more than 93% of their N from the soil. In contrast, 40% of N in the intercropped field pea was derived from soil. This study provided no evidence for transfer of N from the legume to the cereal. On average, the proportion of N derived from air by both pea intercrops was 39% higher than that derived by the sole-cropped pea. Root length determined by a grid intersection method following digitization using an image analyzer tended to be higher under intercropping than in sole crops. We conclude that even on fertile soils benefits may accrue from annual intercropping that includes a legume. The benefits arise from (1) increased N production, (2) greater N-fixation efficiency, and/or (3) more shoot and root residue-N mineralization for subsequent crops.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00337231
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 96
    Digitale Medien
    Digitale Medien
    Resin-core and buried-bag estimates of nitrogen transformations in Costa Rican lowland rainforests (1992)
    Springer
    Plant and soil 139 (1992), S. 275-283 
    Details
    ISSN: 1573-5036
    Schlagwort(e): early-successional forest ; gross N mineralization ; moist tropics ; N immobilization ; 15N ; nutrification ; nutrient cycling ; old-growth forest
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We compared the resin-core and buried-bag incubation methods for estimating nitrogen (N) transformation rates using the 15N pool dilution technique in alluvial soils of an early successional forest (ESF) and an old-growth forest (OGF) at the La Selva Biological Station in Costa Rica. Soil cores (38×100-mm) from both forests were incubated in situ for 7 days. The two methods gave generally similar estimates of net N mineralization rates for the two forests. Estimates of ammonium production by the resin-core method were higher than those by the buried-bag method in ESF, but did not differ significantly in OGF (p〈0.05). Estimates of nitrate production by the two methods did not differ significantly. Nitrate averaged 74% and 81% of the total inorganic N production in ESF and OGF, respectively. Net N mineralization in ESF (6.6 mmol m-2d-1) did not differ significantly from that in OGF (5.0 mmol m-2d-1). Fluxes of ammonium and nitrate were high for both forests, but the OGF tended to have higher gross mineralization and nitrification rates than ESF. Approximately 60% of the gross nitrate production and less than 30% of the ammonium were immobilized by microorganisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009319
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 97
    Digitale Medien
    Digitale Medien
    Interception and uptake of NH4 and NO3 from wet deposition by above-ground parts of young beech (Fagus silvatica L.) trees (1992)
    Springer
    Plant and soil 142 (1992), S. 273-279 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Fagus silvatica L. ; wet deposition ; N-uptake ; 15N
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Uptake of NH4 and NO3 by above ground parts of beech trees was studied by spraying young trees with varying concentrations of 15N labeled solutions, different N-forms, and spray regimes over four months. Following treatment, the trees were harvested and analyzed for 15N and major element content. Throughfall was collected and analyzed in addition in order to study the interaction between nitrogen uptake and cation leaching. Significant amounts of N were taken up by the above ground plant parts in all treatments as indicated by 15N analysis of the trees as well as by throughfall measurements. NH4 uptake exceeded the uptake of NO3 if applied in the same concentration. Uptake of N increased linearly with increasing concentration in the spray solution and with spray intensity. The uptaken N was translocated within the plant. The contribution of N from uptake by above ground parts to the total N content of tissues differed and reached a maximum level of 6% in leaves. No effect of above ground N uptake on the total N content of tissues was found. Calculating atmospheric N inputs to forest ecosystems by throughfall measurements may underestimate the actual N input.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010972
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 98
    Digitale Medien
    Digitale Medien
    Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines (1992)
    Springer
    Plant and soil 147 (1992), S. 49-57 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium ; field ; kiwifruit ; 15N ; nitrogen fertilizer ; recovery ; soil nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The fate of 15N-labelled ammonium fertilizer applied once to six-year-old field-grown kiwifruit (Actinidia deliciosa ‘Hayward’) vines was measured over three years. The three main treatments were nitrogen (N) applied singularly at 100 or 200 kg N ha−1 in early spring (two weeks before bud burst) or split with 100 kg N ha−1 (unlabelled) in early spring and 100 kg N ha−1 (15N-labelled) ten weeks later. All N treatments were applied to vines with a history of either 50 or 200 kg N ha−1 yr−1. For three years after 15n application, components of the vines and soil (0–600 mm depth) were sampled at harvest in late autumn and the N and 15N contents determined. By the first harvest, all plant uptake of 15N had occurred and this represented 48–53% of the 15N applied. There was no significant effect of current N fertilizer treatment or of N history on 15N recovery by vines. Removal of 15N in harvested fruit was small at 5–6% in the first year and 8% over 3 years. After 2–3 years, most plant 15N occurred in the roots and this component declined only slowly over time. In contrast, there was a large temporal decline in 15N in above-ground plant components due to the annual ‘removal’ in leaf fall and pruning. An associated experiment showed that when 15N-labelled prunings and leaves were mulched and returned to the soil, only about 9% was recovered by plants within 2 years. Almost all remaining mulched material had been immobilised into the soil organic N. In all treatments, about 20% of the added 15N remained in soil at the first harvest. This was almost entirely in organic fractions (〈0.4% in inorganic N) and mostly in the surface 150-mm layer. The 15N content in soil changed little over time (from 20 to 17% between the first and third harvests respectively) and indicated that most of the N had been immobilised into stable humus forms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009370
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 99
    Digitale Medien
    Digitale Medien
    Variations in 15N abundance in a forest fertilization trial: Critical loads of N, N saturation, contamination and effects of revitalization fertilization (1992)
    Springer
    Plant and soil 142 (1992), S. 211-219 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 15N ; forest decline ; nitrogen deposition ; revitalization fertilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract 15N abundances of current needles of Norway spruce collected during 23 yrs of a forest fertilization experiment were studied in order to follow ecosystem gains and losses of N. Unlabelled ammonium nitrate at four rates (N0–N3), phosphorus at three rates (P0–P2), and potassium plus other elements including micronutrients at two rates (K0–K1), had been applied to plots in a complete factorial design. Nitrogen had been applied annually at average rates of 0, 34, 68 and 102 kg N ha-1 yr-1. Tree growth had responded positively to additions of N, but the response was remarkably more positive to the N2P2K1 treatment. In N1 treatments, δ15N (‰) declined over time. This was consistent with an earlier study, and should reflect a change in 15N abundance towards that of fertilizer N (minus discrimination during uptake), which in turn means accretion of most of the N added. As in the earlier study, in which N3 plots lost most of the N added, the present N3 plots showed an increasing δ15N (‰). This pattern was not significantly affected by additions of P and K plus other elements, although a weak negative effect of P on N accretion was indicated, i.e. there was a tendency δ15N (‰) to be higher when P was added. This, and another recent result based on an N budget, shows that so-called revitalization fertilization may well increase growth of trees, but also promotes losses of N from the ecosystem. As in the previous study, a decline in δ15N (‰) on control plots provided evidence of contamination. Given a removal of 100 kg N ha-1 at stem harvest and a leaching of 2 kg N ha-1 yr-1, our data on 15N suggest that a load of 9 kg N ha-1 yr-1 would saturate the ecosystem after 100 years. This load is only about twice the annual deposition at the site.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010967
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 100
    Digitale Medien
    Digitale Medien
    Effects of variations in soil water potential, depth of N placement, and cultivar on postanthesis N uptake by wheat (1992)
    Springer
    Plant and soil 143 (1992), S. 45-53 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 15N ; nitrogen harvest index ; nitrogen uptake efficiency ; soil water potential ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This study was conducted to investigate the influence of soil water potential, depth of N placement, timing, and cultivar on uptake of a small dose of labeled N applied after anthesis by wheat (Triticum aestivum L.) Understanding postanthesis N accumulation should allow better control of grain protein concentration through proper manipulation of inputs. Two hard, red spring-wheat cultivars were planted in early and late fall each yr of a 2-yr field experiment. Less than 1 kg N ha−1 as K 15NO3 was injected into the soil at two depths: shallow (0.05 to 0.08 m) and deep (0.15 to 0.18 m). In both years an irrigation was applied at anthesis, and injections of labeled N were timed 4, 12, and 20 days after anthesis (DAA). Soil water potential was estimated at the time of injection. Mean recovery of 15N in grain and straw was 57% of the 15N applied. Recovery did not differ between the high-protein (Yecora Rojo) and the low-protein (Anza or Yolo) cultivars. Mean recovery from deep placement was 60% versus only 54% from shallow placement (p 〈 0.01). Delaying the time of injection decreased mean recovery significantly from 58% at 4 DAA to 54% at 20 DAA. This decrease was most pronounced in the shallow placement, where soil drying was most severe. Regressions of recovery on soil water potential of individual cultivar x yr x planting x depth treatments were significant only under the driest conditions. Stepwise regression of 15N recovery on soil water potential and yield parameters using data from all treatments of both years resulted in an equation including soil water potential and N yield, with a multiple correlation coefficient of 0.64. The translocation of 15N to grain was higher (0.89) than the nitrogen harvest index (0.69), and showed a highly significant increase with increase in DAA. This experiment indicates that the N uptake capacity of wheat remains reasonably constant between 4 and 20 DAA unless soil drying is severe.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009127
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...