ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (64)
  • 15N  (64)
  • 1990-1994  (64)
  • 1960-1964
  • 1950-1954
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (64)
Collection
  • Articles  (64)
Source
Keywords
Publisher
Years
Year
Topic
  • 1
    Electronic Resource
    Electronic Resource
    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
    Keywords: A-value ; Bradyrhizobium ; Genotype ; Growth stage ; 15N ; Nitrogen fixation ; Nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647672
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    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
    Keywords: 15N ; residual N ; Sesbania ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    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
    Keywords: Nutrient cycle ; Coniferous forest ; Soil properties ; 15N ; Acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337740
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    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
    Keywords: Organic matter ; Extracellular enzymes ; Solubilization ; Mineral N ; Total soluble N ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418669
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    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
    Keywords: alfalfa ; bi-directional N transfer ; bromegrass ; long-term N transfer ; short-term N transfer ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    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
    Keywords: ammonium nitrate ; green manure ; incorporation of plant material ; 15N ; N loss ; N mineralization ; NO emission ; oilseed rape ; organic N pool
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010146
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    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
    Keywords: mobile N ; N transfer ; 15N ; root damage ; stored N ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008331
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Fertilization rates and clay fixed ammonium in two Quebec soils (1994)
    Springer
    Plant and soil 163 (1994), S. 103-109 
    Details
    ISSN: 1573-5036
    Keywords: soil mineralogy ; 15N ; clay fixed ammonium ; fertilizer rate ; fertilizer nitrogen recovery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00033946
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    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
    Keywords: aqua ammonia ; di-ammonium phosphate ; gamma-irradiated soil ; 15N ; organic matter solubility ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00748773
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    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
    Keywords: ammonium ; arctic plants ; nitrate reductase ; nitrogen uptake ; 15N ; root temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009280
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    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
    Keywords: 15N ; Cucumis sativus ; Glomus intraradices ; hyphal N transport ; plant N status ; VA mycorrhiza
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00150340
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    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
    Keywords: Urease inhibitors ; Urea N efficiency ; 15N ; Ryegrass ; Hydroquinone (HQ) ; Phenyl phosphorodiamidate (PPDA) ; N-(n-butyl) phosphorothioic triamide (NBPT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00361616
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    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
    Keywords: A N value ; 15N ; Nitrogen fixation ; Glycine max ; Hordeum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369309
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    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
    Keywords: N2 fixation ; N-supplying ability ; 15N ; Arachis hypogaea ; Intercropping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00361614
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    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
    Keywords: Manures ; N mineralisation ; N uptake ; 15N ; Added nitrogen interactions ; Priming effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    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
    Keywords: N2 fixation ; Ontogeny ; 15N ; Vigna radiata ; Vigna mungo ; Vigna unguiculata ; Arachis hypogaea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369413
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    15N Abundance of forests is correlated with losses of nitrogen (1993)
    Springer
    Plant and soil 157 (1993), S. 147-150 
    Details
    ISSN: 1573-5036
    Keywords: 15N ; forest soils ; N deposition ; N losses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00038758
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    15N Abundance of forests is correlated with losses of nitrogen (1993)
    Springer
    Plant and soil 157 (1993), S. 147-150 
    Details
    ISSN: 1573-5036
    Keywords: 15N ; forest soils ; N deposition ; N losses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02390237
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    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
    Keywords: crimson clover ; field labeling ; legume ; nitrogen ; 15N ; variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029095
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    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
    Keywords: air pollution ; ammonia ; ammonium ; 15N ; N concentration ; needle ; pine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012996
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    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
    Keywords: urine ; nitrous oxide ; dinitrogen ; nitrification ; denitrification ; carbon ; 15N ; nitrification inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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}
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010793
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    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
    Keywords: ammonium uptake ; cereals ; kinetics ; legumes ; 15N ; nitrate uptake ; translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011073
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    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
    Keywords: ammonium nitrate ; barley ; fertilizer efficiency ; 15N field experiment ; N recovery ; 15N ; plant uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    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
    Keywords: clover ; grass ; leaching ; lysimeter ; nitrogen ; 15N ; nutrient balances ; nutrient uptake ; pasture ; subsoiling ; sulphur ; 35S
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025061
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    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
    Keywords: Broadcast ; loam soil ; 15N ; N losses ; N recovery ; row application ; split dressing ; sugar beet ; winter wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025059
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    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
    Keywords: 15N ; microbial biomass ; nitrogen uptake efficiency ; Oryza sativa ; soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025057
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    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
    Keywords: Leaching ; calcium ; magnesium ; potassium ; nitrate ; tropical soils ; 15N ; urea ; shifting cultivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01051280
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    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
    Keywords: 15N ; nitrogen ; rice ; soil N ; N fertilizer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01054394
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    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
    Keywords: Nitrogen balance ; 15N ; oxamide ; slow release fertilizer ; soil microbial biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01058011
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    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
    Keywords: Decomposition ; Litter ; Microarthropods ; Nitrogen ; 15N ; Litterbags ; Cornus florida ; Quercus prinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336039
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    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
    Keywords: Nitrification inhibitor ; Dicyandiamide ; 15N ; Incubation ; Temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337229
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    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
    Keywords: Typic cryoboroll ; N yield ; 15N ; Root length ; Grass-legume intercrop ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337231
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    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
    Keywords: early-successional forest ; gross N mineralization ; moist tropics ; N immobilization ; 15N ; nutrification ; nutrient cycling ; old-growth forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009319
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    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
    Keywords: Fagus silvatica L. ; wet deposition ; N-uptake ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010972
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    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
    Keywords: ammonium ; field ; kiwifruit ; 15N ; nitrogen fertilizer ; recovery ; soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009370
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    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
    Keywords: 15N ; forest decline ; nitrogen deposition ; revitalization fertilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010967
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    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
    Keywords: 15N ; nitrogen harvest index ; nitrogen uptake efficiency ; soil water potential ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Biological nitrogen fixation in trees in agro-ecosystems (1992)
    Springer
    Plant and soil 141 (1992), S. 177-196 
    Details
    ISSN: 1573-5036
    Keywords: A-value ; acetylene reduction assay ; agroforestry ; isotope dilution ; 15N ; nitrogen fixation ; nodules ; trees ; ureide technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The integration of trees, especially nitrogen fixing trees (NFTs), into agroforestry and silvo-pastoral systems can make a major contribution to sustainable agriculture by restoring and maintaining soil fertility, and in combating erosion and desertification as well as providing fuelwood. The particular advantage of NFTs is their biological nitrogen fixation (BNF), their ability to establish in nitrogen-deficient soils and the benefits of the nitrogen fixed (and extra organic matter) to succeeding or associated crops. The importance of NFTs leads to the question of how we can maximise or optimize their effects and how we can manage BNF and the transfer of nitrogen to associated or succeeding plantings. To be able to achieve these goals, suitable methods of measuring BNF in trees are necessary. The total nitrogen difference (TND) method is simple, but is better suited for low than high soil N conditions. The acetylene reduction assay (ARA), although sensitive and simple, has many technical limitations especially for NFTs, and the estimates of BNF have generally been very low, compared to other methods. For NFTs, the 15N techniques are still under development, but have already given some promising results (e.g., has been used to measure large genetic variability in BNF within different NFTs). Various factors affect BNF in trees. They include the age of trees, the microbial component, soil moisture, temperature, salinity, pH, soil N level and plant nutrient deficiencies. Some of the factors, e.g. temperature, affect the symbiosis more than plant growth, and differences in the effects of these factors on BNF in different NFT genotypes have been reported. These factors and research needs for improving BNF in trees are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Nitrogen accumulation in sole and mixed stands of sweet-blue lupin (Lupinus angustifolius L.), ryegrass and oats (1992)
    Springer
    Plant and soil 142 (1992), S. 135-142 
    Details
    ISSN: 1573-5036
    Keywords: intercropping ; isotope dilution ; Lupinus angustifolius ; 15N ; nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nitrogen fixation was measured in monocropped sweet-blue lupin (Lupinus angustifolius), lupin intercropped with two ryegrass (Lolium multiflorum) cultivars or with oats (Avena sativa) on an Andosol soil, using the 15N isotope dilution method. At 117 days after planting and at a mean temperature below 10°C, monocropped lupin derived an average of 92% or 195 kg N ha−1 of its N from N2 fixation. Intercropping lupin with cereals increased (p〈0.05) the percentage of N derived from atmospheric N2 (% Ndfa) to a mean of 96%. Compared to the monocropped, total N fixed per hectare in intercropped lupin declined approximately 50%, in line with the decrease in seeding rate and dry matter yield. With these high values of N2 fixation, selection of the reference crop was not a problem; all the cereals, intercropped or grown singly produced similar estimates of N2 fixed in lupin. It was deduced from the 15N data that significant N transfer occurred from lupin to intercropped Italian ryegrass but not to intercropped Westerwoldian ryegrass or to oats. Doubling the 15N fertilizer rate from 30 to 60 kg N ha−1 decreased % Ndfa to 86% (p〈0.05), but total N fixed was unaltered. These results indicate that lupin has a high potential for N2 fixation at low temperatures, and can maintain higher rates of N2 fixation in soils of high N than many other forage and pasture legumes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010183
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Influence of time of application on the utilization of nitrogen fertilizer by asparagus, estimated using 15N (1992)
    Springer
    Plant and soil 147 (1992), S. 41-47 
    Details
    ISSN: 1573-5036
    Keywords: asparagus ; Asparagus officinalis ; nitrogen fertilizer ; 15N ; plant uptake ; soil nitrogen fractions ; time of application
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of nitrogen (N) fertilizer on the production of a 6-year-old asparagus (Asparagus officinalis L.) crop was examined over 2 years by the application of 0, 50 or 100 kg N ha−1 as ammonium sulphate at three times; 1) prior to fern growth (9 months before harvest), 2) prior to harvest, or 3) early-harvest prior to the main period of spear production. The utilization of N fertilizer was examined by applying 15N-enriched ammonium sulphate to 2 m×2.5 m microplost within the 50 kg N ha−1 treatments. There was a 12% response in spear production to added N in the first harvest year only and there was no significant effect of rate or time of N application. Plant uptake of added 15N by the end of the first harvest period was 25, 11 and 4% of the total applied for the pre-fern, pre-harvest and early-harvest treatments respectively. About 60% of the 15N applied pre- or early-harvest remained in the soil at the end of the first harvest period. Most of the 15N in soil in the pre-harvest treatment occurred as inorganic N and had been leached into the 150–600 mm soil depth. In contrast, most of the 15N that remained in soil from the early-harvest application was in the 0–75 mm depth and 40% of this had been immobilized into organic N. In the short-term (less than one year), utilisation of 15N-labelled N fertilizer by asparagus was greatest when applied prior to fern growth. However, after 2 years there was no difference between treatments in 15N recovery in plant or soil. Thus, time of application of N fertilizer had no long-term effect on production or utilization of N fertilizer by asparagus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009369
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines (1992)
    Springer
    Plant and soil 147 (1992), S. 59-68 
    Details
    ISSN: 1573-5036
    Keywords: kiwifruit ; 15N ; plant uptake ; remobilisation ; temporal changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Temporal changes in the nitrogen (N) and 15N content of various components of six-year-old kiwifruit (Actinidia deliciosa ‘Hayward’) vines which had received 15N-labelled ammonium fertilizer were measured. The fertilizer was 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 treatments were applied to vines with a history of either 50 or 200 kg N ha−1 yr−1. The N concentration of leaf and fruit tissue was generally lower in the 100 kg N ha−1 treatment than in the 200 kg N ha−1 treatments and this effect was greater than that of N fertilizer history. During the first 8 weeks after bud burst there was a rapid accumulation of N in leaves (ca. 80 kg N ha−1). Analysis of xylem sap at 4 weeks after bud burst revealed that about 60% of the N utilised for new growth was from remobilisation of N stored within the vines and about 40% from soil and fertilizer N. This was unaffected by rate of N application. Plant uptake of added 15N was rapid and almost complete within 10 weeks of application in either early spring or early summer. Initially, most 15N was present in the leaf and root components but these subsequently declined due to translocation into other components of the vine. The decline in leaf 15N coincided with an equivalent accumulation of 15N in the fruit. The 15N enrichment of the ‘annual’ components (leaves, fruit and current-season's shoots) was about twice that of the structural components (one-year-old shoots, cordon, stem and structural roots) during the first year after application. By the third year the 15N concentration of the annual components had declined to similar levels to that of the structural components. These changes were used to estimate the annual throughput of N from soil in vines which received no N fertilizer in years 2 and 3 at 50% of total above-ground N and only 7% in roots. This was equivalent to about 120 kg N ha−1 yr−1. Where fertilizer N (200 kg ha−1) was applied in year 2 the annual throughput of N from soil and fertilizer was about 170 kg N ha−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009371
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Phosphorus requirements and nitrogen accumulation by three mungbean (Vigna radiata (L) Welzek) cultivars (1992)
    Springer
    Plant and soil 147 (1992), S. 267-274 
    Details
    ISSN: 1573-5036
    Keywords: fertilizer ; genotype ; isotope dilution ; legume ; 15N ; nitrogen fixation ; nodule ; phosphorus use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A promising approach for overcoming poor crop yields in phosphorus (P)-deficient soils is to exploit the genetic variation among plants to grow under low P conditions. We examined the P requirements of three mungbean cultivars, T-77, MI-5 and E-72, using four P rates, 0, 30, 60 and 90 mg P kg-1 soil (designated P0, P1, P2 and P3, respectively). Nodulation was highest in T-77, and unlike the other cultivars, nodule numbers were not increased by P application. Similarly, growth of T-77 was the highest, and was not influenced by P rates. In contrast shoot yields of MI-5 and E-72 at P0 were only 76 and 65%, respectively, of the maximum obtained under P application. Nodule dry weight and the amount of N fixed (Ndfa) in each cultivar was enhanced by P application, with T-77 generally giving the lowest response, and accumulating the highest Ndfa. The data suggest a higher P requirement for N2 fixation (especially for T-77) than for growth. All plants increased their P uptake as P rates increased, with T-77 accumulating the highest amount of P at each P level. Differences in the physiological P use efficiency, PPUE (g shoot mg-1 P) among genotypes were generally not significant, neither were there any consistent trends as P rates changed. The ability to absorb P therefore appeared to be more important than PPUE in enhancing growth. We conclude from our data that it is possible by selection to obtain plants capable of good growth and high N2 fixation in soils of low P; cultivar T-77 is a good example.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029078
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    13C isotope discrimination correlates with biological nitrogen fixation in soybean (Glycine max (L.) Merrill) (1992)
    Springer
    Plant and soil 139 (1992), S. 145-147 
    Details
    ISSN: 1573-5036
    Keywords: 13C ; carbon isotope discrimination ; 15N ; % Ndfa ; N2 fixation ; salinity ; soybeans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A preliminary study was conducted on greenhouse-grown soybean plants to investigate if carbon isotope (13C) discrimination (Δ) is related with the capacity to fix atmospheric nitrogen (N2). Seven soybean (Glycine max (L.) Merrill) cultivars (Goldsoy, A-100, Lee, Ada, D61-2694, Alto and Evans) inoculated with a mixture of Bradyrhizobium japonicum were tested. A salinity treatment imposed on one set of plants increased the range in Δ (18.72 × 103 − 19.56 × 103 without salinity to 18.72 × 103 − 20.36 × 103 with salinity) and N2 fixation (79.4%–84.9% without salinity to 73.6%–84.9% with salinity) attainable in the seven cultivars studied. For the full range of treatments, Δ was negatively correlated (r=−0.62*) with N2 fixation. Thus, subject to confirmation from further study, Δ may prove a useful tool in the selection of legume genotypes with a high capacity for N2 fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012852
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    The role of VAM fungi in nitrogen dynamics in maize-bean intercrops (1992)
    Springer
    Plant and soil 144 (1992), S. 85-92 
    Details
    ISSN: 1573-5036
    Keywords: beans (Phaseolus vulgaris L.) ; Costa Rica ; dystrandept ; intercropping ; maize (Zea mays L.) ; N transfer ; 15N ; VAM fungi (Glomus etunicatum)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nitrogen (N) transfer from N-fixing legumes via vesicular-arbuscular mycorrhizal (VAM) fungi to associated non-fixing plants has been demonstrated in greenhouse experiments. To date, this transfer has been shown only where mineral N is applied shortly before harvest, and hence is readily available. We have yet to demonstrate VAM-mediated N transfer where soil-N is limiting, a condition under which most traditional legume-nonlegume intercrops are grown. In this study, 15N-enriched soil (with 0.28%N) was used to distinguish between the uptake of soil- and atmospherically-derived N in maize grown with beans in the presence or absence of VAM fungi. VAM infection did not result in transfer of fixed N or soil N from bean to maize, despite a VAM-stimulated increase in N fixation in bean. In fact, beans were more competitive for soil N when mycorrhizal. N content in beans increased by 75% with a concomitant 22% decrease in mg N per maize plant. The competitive effect may have resulted from a VAM-mediated shift in carbon allocation in beans (but not maize) from shoots to roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018848
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Evaluation of reference plants by labelling with 35S in the estimation of N2 fixation by 15N isotope dilution (1992)
    Springer
    Plant and soil 145 (1992), S. 177-185 
    Details
    ISSN: 1573-5036
    Keywords: isotope dilution ; lupins ; 15N ; 35S ; symbiotic N2 fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Lupins, canola, ryegrass and wheat fertilized with Na2 35SO4 and either 15NH4Cl or K15NO3(N:S=10:1), were grown in the field in unconfined microplots, and the sources of N and S (fertilizer, soil, atmosphere, seed) in plant tops during crop development were estimated. Modelled estimates of the proportion of lupin N derived from the atmosphere, which were obtained independently of reference plants, were used to calculate the proportion of lupin N derived from the soil. Total uptake of N and S and uptake of labelled N and S increased during crop development. Total uptake of S by canola was higher than lupins, but labelled S uptake by lupins exceeded uptake by canola. The form of N applied had no effect on uptake of labelled and unlabelled forms of N or S. Ratios of labelled to unlabelled S and ratios of labelled to unlabelled N derived from soil sources decreased during growth, and were less for S than for N for each crop at each sampling time. Although ratios of labelled to unlabelled soil-derived N were similar between crops at 155, 176 and 190 days after sowing, ratios of labelled to unlabelled S for lupins were higher than for the reference crops and declined during this period. The ratios of labelled to unlabelled S in lupins and the reference plants therefore bore no relationship either to ratios of labelled to unlabelled soil-derived N in the plants, or to total S uptake by the plants. Therefore the hypothesis that equal ratios of labelled N to unlabelled soil-derived N in legumes (Rleg) and reference plants (Rref) would be indicated by equal ratios of labelled to unlabelled S was not supported by the data. The results therefore show that the accuracy of reference plant-derived values of Rleg cannot be evaluated by labelling with 35S.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010346
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Availability of soil and fertilizer nitrogen to wetland rice following wheat straw amendment (1991)
    Springer
    Biology and fertility of soils 11 (1991), S. 97-100 
    Details
    ISSN: 1432-0789
    Keywords: Added N interaction ; Fertilizer N ; 15N ; Organic amendment ; Oryza sativa ; Wetland rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A pot experiment was conducted to study the availability of soil and fertilizer N to wetland rice as influenced by wheat straw amendment (organic amendment) and to establish the relative significance of the two sources in affecting crop yield. Straw was incorporated in soil at 0.1, 0.2, and 0.3% before transplanting rice. Inorganic N as 15N-ammonium sulphate was applied at 30, 60, and 90 μg g-1 soil either alone or together with wheat straw in different combinations. After harvesting the rice, the plant and soil samples were analyzed for total N and 15N. Straw incorporation significantly decreased the dry matter and N yield of rice, the decrease being greater with higher rates of straw. The reduction in crop yield following the straw incorporation was attributed mainly to a decrease in the uptake of soil N rather than fertilizer N. The harmful effects of organic matter amendment were mitigated by higher levels of mineral N addition. The uptake of applied N increased and its losses decreased due to the straw incorporation. Mineral N applied alone or together with organic amendment substantially increased the uptake of unlabelled soil N. The increase was attributed to a real added N interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336371
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Effect of encapsulated calcium carbide on dinitrogen, nitrous oxide, methane, and carbon dioxide emissions from flooded rice (1991)
    Springer
    Biology and fertility of soils 11 (1991), S. 116-120 
    Details
    ISSN: 1432-0789
    Keywords: Denitrification ; Flooded soil ; 15N ; Urea ; Wetland rice ; Oryza sativa L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The efficiency of N use in flooded rice is usually low, chiefly due to gaseous losses. Emission of CH4, a gas implicated in global warming, can also be substantial in flooded rice. In a greenhouse study, the nitrification inhibitor encapsulated calcium carbide (a slow-release source of acetylene) was added with 75, 150, and 225 mg of 75 atom % 15N urea-N to flooded pots containing 18-day-old rice (Oryza sativa L.) plants. Urea treatments without calcium carbide were included as controls. After the application of encapsulated calcium carbide, 3.6 μg N2, 12.4 μg N2O-N, and 3.6 mg CH4 were emitted per pot in 30 days. Without calcium carbide, 3.0 mg N2, 22.8 μg N2O-N, and 39.0 mg CH4 per pot were emitted during the same period. The rate of N added had a positive effect on N2 and N2O emissions, but the effect on CH4 emissions varied with time. Carbon dioxide emissions were lower with encapsulated calcium carbide than without. The use of encapsulated calcium carbide appears effective in eliminating N2 losses, and in minimizing emissions of the “greenhouse gases” N2O and CH4 in flooded rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336375
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Soil N dynamics and N yield of barley grown on Breton loam using N from biological fixation or fertilizer (1991)
    Springer
    Biology and fertility of soils 12 (1991), S. 10-18 
    Details
    ISSN: 1432-0789
    Keywords: Agroecological rotation ; Hordeum vulgare ; Microbial biomass ; 15N ; Rotation effects ; Pot experiment ; Soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soil N dynamics and barley yields (Hordeum vulgare L.) were compared in pot experiments using surface samples from a Gray Luvisol under three cropping systems at Breton, Alberta: (1) an agroecological 8-year rotation including cereals, forage, and fababeans (Vicia faba L.) as green manure, from wich two plots were selected, one following fababeans, and the second following 3 years of forage; (2) a continuous grain system, with fertilizer N at 90 kg ha-1 year-1; and (3) a classical Breton 5-year rotation [following oats (Avena sativa L.)] involving forage and cereals, without returning crop residues to the land, selecting one plot with PKS treatment and a second as control. The fertilizer N equivalent for the cropping system; “AN” value and “A” value (analogous to AN), but in fertilizer 15N units, soil biomass, and C and N mineralization were monitored. In the first agroecological plot (after fababeans), grain and total plant biomass production were 116% greater than from the continuous grain treatment. Barley plants in the two agroecological plots derived 48.5% and 37.8%, respectively, of their N requirement from non-labelled soil N sources not present in the continuous grain plot. At crop maturity, the recovery of 15N microbial biomass was 1.5 times higher in soil from the first agroecological plot than from the continuous grain plot. The fertilizer N equivalent was 2670 mg pot-1 (485 kg ha-1) for the first and 1850 mg pot-1 for the second agroecological treatment. Fertilizer N equivalent values exceed net amounts of N mineralized by a factor of 4. Recovery by the barley crop of 15N added at 55 mg pot-1 was more efficient in the agroecological treatments (45%–51%) than in the continuous grain or classical Breton treatments (35%–37%). It was concluded (1) that past soil history may be associated more with the ability of barley plants to compete for available N, and hence the use of N, than with net soil N mineralization; and (2) an increased supply of N to crops following the incorporation of fababean residues, manure application, and the soil N-conserving effect of growing legumes were all partly responsible for the observed differences in soil fertility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369382
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    The use of mean pool abundances to interpret 15N tracer experiments (1991)
    Springer
    Plant and soil 131 (1991), S. 89-96 
    Details
    ISSN: 1573-5036
    Keywords: ammonium ; mineralization ; nitrate ; nitrification ; 15N ; plant ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Details are presented of a simple mathematical framework that allows 15N tracer experiments to be interpreted in terms of the main processes of the soil/plant nitrogen cycle. The calculations, all of which can be performed on a scientific calculator, yield the rates of gross mineralization and nitrification and the crop nitrogen uptake occurring as ammonium and nitrate. Two procedures are presented. One requires paired experiments with labelled ammonium and unlabelled nitrate as one treatment, and unlabelled ammonium and labelled nitrate as the other. The second procedure requires only the labelled ammonium, unlabelled nitrate treatment. Example calculations are presented using actual experimental data. The interpretative procedure uses the fact that the rate of isotopic dilution in an ammonium pool labelled with 15N is a function of the rate at which unlabelled ammonium is introduced into the pool via mineralization. Similarly, the rate of isotope dilution in an 15N labelled nitrate pool is a function of the rate at which unlabelled nitrate is introduced into the pool via nitrification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010423
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    The use of mean pool abundances to interpret 15N tracer experiments (1991)
    Springer
    Plant and soil 131 (1991), S. 97-105 
    Details
    ISSN: 1573-5036
    Keywords: ammonium ; mineralization ; nitrate ; nitrification ; 15N ; plant ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pulse dilution 15N technique was used in the field to determine the effect of the ammonium to nitrate ratio in a fertilizer application on the uptake of ammonium and nitrate by ryegrass and on gross rates of mineralization and nitrification. Two experiments were performed, corresponding approximately to the first and second cuts of grass. Where no substantial recent immobilization of inorganic nitrogen had occurred, mineralization was insensitive to the form of nitrogen applied, ranging from 2.1–2.6 kg N ha-1 d-1. The immobilization of ammonium increased as the proportion of ammonium in the application increased. In the second experiment there was evidence that high rates of immobilization in the first experiment were associated with high rates of mineralization in the second. The implication was that some nitrogen immobilized in the first experiment was re-mineralized during the second. Whether this was nitrogen taken up, stored in roots and released following defoliation was not clear. Nitrification rates in this soil were low (0.1–0.63 kg N ha-1 d-1), and as a result, varying the ratio of ammonium to nitrate applied markedly altered the relative uptake of ammonium and nitrate. In the first experiment, where temperatures were low, preferential uptake of ammonium occurred, but where 〉90% of the uptake was as ammonium, a reduction in yield and nitrogen uptake was observed. In the second experiment, where temperatures and growth rates were higher, the proportion of ammonium to nitrate taken up had no effect on yield or nitrogen uptake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010424
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    The contribution of associative and symbiotic nitrogen fixation to the nitrogen nutrition of non-legumes (1991)
    Springer
    Plant and soil 132 (1991), S. 29-39 
    Details
    ISSN: 1573-5036
    Keywords: actinorhizal plants ; associative nitrogen fixation ; cereals ; grasses ; isotope dilution ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract During the past 10 years estimates of N2 fixation associated with sugar cane, forage grasses, cereals and actinorhizal plants grown in soil with and without addition of inoculum have been obtained using the 15N isotope dilution technique. These experiments are reviewed in this paper with the aim of determining the proportional and absolute contribution of N2 fixation to the N nutrition of non-legumes, and its role as a source of N in agriculture. The review also identifies deficiencies in both the totality of data which are currently available and the experimental approaches used to quantify N2 fixation associated with non-legumes. Field data indicate that associative N2 fixation can potentially contribute agronomically-significant amounts of N (〉30–40 kg N ha-1 y-1) to the N nutrition of plants of importance in tropical agriculture, including sugar cane (Saccharum sp.) and forage grasses (Panicum maximum, Brachiaria sp. and Leptochloa fusca) when grown in uninoculated, N-deficient soils. Marked variations in proportions of plant N derived from the atmosphere have been measured between species or cultivars within species. Limited pot-culture data indicate that rice can benefit naturally from associative N2 fixation, and that inoculation responses due to N2 fixation can occur. Wheat can also respond to inoculation but responses do not appear to be due to associative N2 fixation. 15N dilution studies confirm that substantial amounts of N2 can be fixed by actinorhizal plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011009
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Nitrogen fixation by white clover when competing with grasses at moderately low temperatures (1991)
    Springer
    Plant and soil 133 (1991), S. 47-56 
    Details
    ISSN: 1573-5036
    Keywords: clover ; competition ; grass ; Lolium perenne ; 15N ; nitrogen fixation ; Phleum pratense ; temperature ; Trifolium repens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract It was the aim of this study to determine the way in which low temperature modifies the effect of a competing grass on nitrogen fixation of a forage legume. White clover (Trifolium repens L.) was grown in monoculture or in different planting ratios with timothy (Phleum pratense L.) or perennial ryegress (Lolium perenne L.) in growth chambers at either 7.5/5°C (LoT) or 15/10°C (HiT) average day/night temperatures, and with 2.5 or 7.5 mM 15N-labelled nitrate in the nutrient solution. Competition with grass led to a marked increase in the proportion of clover nitrogen derived from symbiosis (% Nsym). This increase was slower at LoT where % Nsym was reduced considerably; it was closely related to the reduction in the amount of available nitrate as a result of its being utilized by the grass. Nitrogen concentration in white clover herbage and dry matter yield per clover plant were reduced, for the most part, when a competing grass was present. The amount of nitrogen fixed per plant of white clover decreased markedly with temperature. Low temperature consequently accentuated competition for nitrate. The capacity of white clover to compete successfully was limited by its slower growth and nitrogen accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011898
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Endomycorrhizal fungi in nitrogen transfer from soybean to maize (1991)
    Springer
    Plant and soil 138 (1991), S. 33-40 
    Details
    ISSN: 1573-5036
    Keywords: Glycine max (L.) Merrill ; Glomus versiforme (Karsten) Berch ; interspecific plant interaction ; nitrogen-transfer ; 15N ; Zea mays L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Using 15N as a tracer, interspecific N-transfer was studied during the course of plant development. The use of barriers of differing permeabilities between donor and receiver plants allowed separation of the effect of mycorrhizal colonization, root or hyphal contact and interplant hyphal bridging, on 15N-transfer from soybean (Glycine max (L.) Merrill) to maize (Zea mays L.). More transfer was measured between mycorrhizal plants, but transport of 15N from the labelled host plant to Glomus versiforme (Karsten) Berch did not seem to occur at the symbiotic interface, suggesting that the fungus is independent of its host for its N-nutrition, and that the role of hyphal bridges in N-transfer between plants, is not significant. Uptake by the receiver plant of the N excreted by the donor plant root system appears to be the mechanism of N-transfer between plants. The factor most affecting 15N-transfer between plants was found to be the extent of the contact between plant root systems. The presence of the endomycorrhizal fungus in plant roots reduced 15N-loss from soybean, but at the same time, its extensive hyphal network improved the efficiency of the maize root system for the recovery of the 15N excreted by soybeans. The net result was a better conservation of the N resource within the plant system. The transfer of N between mycorrhizal plants was particularly enhanced by the death of the soybean.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011805
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Endomycorrhizal fungal species mediate 15N transfer from soybean to maize in non-fumigated soil (1991)
    Springer
    Plant and soil 138 (1991), S. 41-47 
    Details
    ISSN: 1573-5036
    Keywords: fumigation ; Glomus intraradices ; G. vesiculiferum ; G. versiforme ; Glycine max, grass-legume mixture ; 15N ; nitrogen transfer ; soil microorganisms ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of mycorrhizal inoculation on 15N transfer from soybean to maize was studied in fumigated and non-fumigated soil. Three Glomus species and a non-inoculated control were compared. In spite of higher levels of root colonization and more abundant hyphae associated with plants growing in fumigated soil, mycorrhizae-enhanced 15N transfer to maize was significant only in non-fumigated plots. High 15N transfer was not only associated with high mycelium density in soil but also with low soil microbial carbon, suggesting that the effect of mycorrhizal fungi on soil microbial populations may be an important factor affecting N transfer between mycorrhizal plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Transfer of fixed nitrogen from white clover to associated grasses in swards grazed by dairy cows, estimated using 15N methods (1991)
    Springer
    Plant and soil 131 (1991), S. 215-223 
    Details
    ISSN: 1573-5036
    Keywords: clover ; grazing effects ; 15N ; nitrogen cycling ; nitrogen fixation ; nitrogen transfer ; Trifolium repens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Pasture swards containing perennial ryegrass (Lolium perenne L.) alone or with one of five different white clover (Trifolium repens L.) cultivars were examined for production and transfer of fixed nitrogen (N) to grass under dairy cow grazing. Grass-only swards produced 21% less than mixed clover-grass swards during the second year after sowing. Production from grass-only plots under a mowing and clipping removal regime was 44% less than from grass-only plots under grazing. Much of this difference could be attributed to N transfer. In swards without clover, the ryegrass component also decreased in favour of other grasses. The average amount of fixed N in herbage from all clover cultivars was 269 kg N ha−1 yr−1. Above-ground transfer of fixed N to grasses (via cow excreta) was estimated at 60 kg N ha−1 yr−1. Below-ground transfer of fixed N to grasses was estimated at 70 kg N ha−1 yr−1 by 15N dilution and was similar for all clover cultivars. Thus, about 50% of grass N was met by transfer of fixed N from white clover during the measurement year. Short-term measurements using a 15N foliar-labelling method indicated that below-ground N transfer was largest during dry summer conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009451
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Denitrification losses from puddled rice soils in the tropics (1990)
    Springer
    Biology and fertility of soils 9 (1990), S. 1-13 
    Details
    ISSN: 1432-0789
    Keywords: Denitrification ; Flooded soil ; 15N ; Nitrogen ; Oryza sativa L. ; Wetland rice ; Urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Although denitrification has long been considered a major loss mechanism for N fertilizer applied to lowland rice (Oryza sativa L.) soils, direct field measurements of denitrification losses from puddled rice soils in the tropics have only been made recently. This paper summarizes the results of direct measurement and indirect estimation of denitrification losses from puddled rice fields and reviews the status of research methodology for measurement of denitrification in rice fields. The direct recovery of (N2+N2O)-15N from 15N-enriched urea has recently been measured at sites in the Philippines, Thailand, and Indonesia. In all 12 studies, recoveries of (N2+N2O)-15N ranged from less than 0.1 to 2.2% of the applied N. Total gaseous N losses, estimated by the 15N-balance technique, were much greater, ranging from 10 to 56% of the applied urea-N. Denitrification was limited by the nitrate supply rather than by available C, as indicated by the values for water-soluble soil organic C, floodwater (nitrate+nitrite)-N, and evolved (N2+N2O)-15N from added nitrate. In the absence of runoff and leaching losses, the amount of (N2+N2O)-15N evolved from 15N-labeled nitrate was consistently less than the unrecovered 15N in 15N balances with labeled nitrate, which presumably represented total denitrification losses. This finding indicates that the measured recoveries of (N2+N2O)-15N had underestimated the denitrification losses from urea. Even with a probable two-or threefold underestimation, direct measurements of (N2+N2O)-15N failed to confirm the appreciable denitrification losses often estimated by the indirect difference method. This method, which determines denitrification losses by the difference between total 15N loss and determined ammonia loss, is prone to high variability. Measurements of nitrate disappearance and 15N-balance studies suggest that nitrification-denitrification occurs under alternate soil drying and wetting conditions both during the rice cropping period and between rice crops. Research is needed to determine the magnitude of denitrification losses when soils are flooded and puddled for production of rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335854
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Evolution of dinitrogen and nitrous oxide from the soil to the atmosphere through rice plants (1990)
    Springer
    Biology and fertility of soils 9 (1990), S. 61-67 
    Details
    ISSN: 1432-0789
    Keywords: Denitrification ; Flooded soil ; 15N ; Urea ; 15N balance ; Wetland rice ; Oryza sativa L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary It is commonly assumed that a large fraction of fertilizer N applied to a rice (Oryza sativa L.) field is lost from the soil-water-plant system as a result of denitrification. Direct evidence to support this view, however, is limited. The few direct field, denitrification gas measurements that have been made indicate less N loss than that determined by 15N balance after the growing season. One explanation for this discrepancy is that the N2 produced during denitrification in a flooded soil remains trapped in the soil system and does not evolve to the atmosphere until the soil dries or is otherwise disturbed. It seems likely, however, that N2 produced in the soil uses the rice plants as a conduit to the atmosphere, as does methane. Methane evolution from a rice field has been demonstrated to occur almost exclusively through the rice plants themselves. A field study in Cuttack, India, and a greenhouse study in Fort Collins, Colorado, were conducted to determine the influence of rice plants on the transport of N2 and N2O from the soil to the atmosphere. In these studies, plots were fertilized with 75 or 99 atom % 15N-urea and 15N techniques were used to monitor the daily evolution of N2 and N2O. At weekly intervals the amount of N2+N2O trapped in the flooded soil and the total-N and fertilized-N content of the soil and plants were measured in the greenhouse plots. Direct measurement of N2+N2O emission from field and greenhouse plots indicated that the young rice plant facilitates the efflux of N2 and N2O from the soil to the atmosphere. Little N gas was trapped in the rice-planted soils while large quantities were trapped in the unplanted soils. N losses due to denitrification accounted for only up to 10% of the loss of added N in planted soils in the field or greenhouse. The major losses of fertilizer N from both the field and greenhouse soils appear to have been the result of NH3 volatilization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335863
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Availability of soil and fertilizer nitrogen to wheat (Triticum aestivum L.) following rice-straw amendment (1990)
    Springer
    Biology and fertility of soils 10 (1990), S. 134-138 
    Details
    ISSN: 1432-0789
    Keywords: 15N ; N immobilization ; N loss ; N uptake ; Rice straw ; Soil N ; Wheat ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A pot experiment was conducted to study the N availability to wheat and the loss of 15N-labelled fertilizer N as affected by the rate of rice-straw applied. The availability of soil N was also studied. The straw was incorporated in the soil 2 or 4 weeks before a sowing of wheat and allowed to decompose at a moisture content of 60% or 200% of the water-holding capacity. The wheat plants were harvested at maturity and the roots, straw, and grains were analysed for total N and 15N. The soil was analysed for total N and 15N after the harvest to determine the recovery of fertilizer N in the soil-plant system and assess its loss. The dry matter and N yields of wheat were significantly retarded in the soil amended with rice straw. The availability of soil N to wheat was significantly reduced due to the straw application, particularly at high moisture levels during pre-incubation, and was assumed to cause a reduction in the dry matter and N yields of wheat. A significant correlation (r=0.89) was observed between the uptake of soil N and the dry matter yield of wheat with different treatments. In unamended soil 31.44% of the fertilizer N was taken up by the wheat plants while 41.08% of fertilizer N was lost. The plant recovery of fertilizer N from the amended soil averaged 30.78% and the losses averaged 45.55%
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336249
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    The relative roles of N fixation, fertilizer, crop residues and soil in supplying N in multiple cropping systems in a humid, tropical upland cropping system (1990)
    Springer
    Plant and soil 121 (1990), S. 73-82 
    Details
    ISSN: 1573-5036
    Keywords: corn ; cowpea ; humid tropics ; multiple cropping ; N fertilizer ; N fixation ; orthoxic ; palehumult ; residues ; soybean ; upland rice ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This work provides information relevant to the nitrogen (N) management strategy of multiple cropping in upland systems in the humid tropics of the transmigration areas of Sumatra, Indonesia. The experiment was conducted on a red yellow podzolic (orthoxic palehumult) soil at Kota Bumi in Lampung Province, Indonesia, where the annual rainfall of 2430 mm allows three consecutive crops per year to be grown. Two sequential systems were studied—rice-soybean-cowpea and rice-corn-cowpea. For each crop, crop residues and fertilizer applied to subplots were labelled with 15N so that the crop N uptake for the planted crop and subsequent crops could be partitioned into that derived from N fixation (legume only), fertilizer, crop residues and soil. The experiment was conducted over two years (6 crops). The percentage of soybean and cowpea N derived from N fixation was 33% for soybean and 12–33% for cowpea. Removal of N in seed exceeded the amount derived from fixation. Efficiency of utilization of fertilizer N ranged from 9–18% of that applied for wet season upland rice (900–1300 mm rainfall) to 32–40% for dry season corn (410–840 mm rainfall). Residual fertilizer N recovery by subsequent erops was as high as 14% of that applied to corn and as low as 2% of that applied to rice. Legume residues were an effective source of N to the following crop, particularly cowpea residues applied to rice, where percent recovery was higher than from fertilizer. Cereal residues were of lower value as a source of N. Percent utilization of N in crop residues by the following crop was related to the % N in the residues and the rainfall received by the following crop (R2=0.69, P=0.01).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013099
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    The relative roles of N fixation, fertilizer, crop residues and soil in supplying N in multiple cropping systems in a humid, tropical upland cropping system (1990)
    Springer
    Plant and soil 122 (1990), S. 73-82 
    Details
    ISSN: 1573-5036
    Keywords: corn ; cowpea ; humid tropics ; multiple cropping ; N fertilizer ; N fixation ; orthoxic ; palehumult ; residues ; soybean ; upland rice ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This work provides information relevant to the nitrogen (N) management strategy of multiple cropping in upland systems in the humid tropics of the transmigration areas of Sumatra, Indonesia. The experiment was conducted on a red yellow podzolic (orthoxic palehumult) soil at Kota Bumi in Lampung Province, Indonesia, where the annual rainfall of 2430 mm allows three consecutive crops per year to be grown. Two sequential systems were studied—rice-soybean-cowpea and rice-corn-cowpea. For each crop, crop residues and fertilizer applied to subplots were labelled with15N so that the crop N uptake for the planted crop and subsequent crops could be partitioned into that derived from N fixation (legume only), fertilizer, crop residues and soil. The experiment was conducted over two years (6 crops). The percentage of soybean and cowpea N derived from N fixation was 33% for soybean and 12–33% for cowpea. Removal of N in seed exceeded the amount derived from fixation. Efficiency of utilization of fertilizer N ranged from 9–18% of that applied for wet season upland rice (900–1300 mm rainfall) to 32–40% for dry season corn (410–840 mm rainfall). Residual fertilizer N recovery by subsequent erops was as high as 14% of that applied to corn and as low as 2% of that applied to rice. Legume residues were an effective source of N to the following crop, particularly cowpea residues applied to rice, where percent recovery was higher than from fertilizer. Cereal residues were of lower value as a source of N. Percent utilization of N in crop residues by the following crop was related to the % N in the residues and the rainfall received by the following crop (R2=0.69,P=0.01).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02444106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Fate and efficiency of N fertilizers applied to pearl millet in Niger (1990)
    Springer
    Plant and soil 125 (1990), S. 221-231 
    Details
    ISSN: 1573-5036
    Keywords: calcium ammonium nitrate (CAN) ; 15N ; urea ; West Africa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field studies were conducted in Niger using 15N-labeled fertilizers to assess the fate and efficiency of fertilizer N in pearl millet (Pennisetum glaucum [L.] R.Br.) production. Total plant uptake of fertilizer N was low in all cases (20%–37%), and losses were severe (25%–53%). The majority of N remaining in the soil was found in the 0- to 15-cm layer though some enrichment at lower depths was found when the N fertilizer was calcium ammonium nitrate (CAN). In a comparison of urea placement methods (band, broadcast, or point placement), no significant differences in 15N uptake or yield were noted though point placement did exacerbate 15N loss. The mechanism of N loss is believed to have been ammonia volatilization. Yields were similar whether urea or CAN was used, but 15N uptake from CAN was higher. A statistical model was developed relating millet yield and N response to midseason rainfall. In drought years, no N response was found, whereas in years of good rainfall a response was found of 15 kg grain for each kilogram of N applied (at 30 kg N ha-1 rate).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Comparative effects of organic and inorganic nitrogen sources applied to a flooded soil on rice yield and availability of N (1990)
    Springer
    Plant and soil 125 (1990), S. 255-262 
    Details
    ISSN: 1573-5036
    Keywords: added N interaction ; flooded soil ; nitrogen availability ; 15N ; priming effect ; rice ; soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot experiment was conducted to study the effect of organic and inorganic nitrogen (N) sources on the yield and N uptake of rice from applied and native soil-N. The residual effect of these N sources on a succeeding wheat crop was also studied. Organic N was applied in the form of 15N-labelled Sesbania aculeata L., a legume, and inorganic N in the form of 15N-labelled ammonium sulphate. The two sources were applied to the soil separately or together at the time of transplanting rice. Recovery of N by rice from both the applied sources was quite low but both sources caused significant increases in biomass and N yield of rice. Maximum increase was recorded in soil treated with organic N. The residual value of the two materials as source of N for wheat was not significant; the wheat took up only a small fraction of the N initially applied. Loss of N occurred from both applied N sources, the losses being more from inorganic N. Both applied N sources caused a substantial increase in the availability of soil-N to rice and wheat; most of this increase was due to organic N and was attributed to the so-called ‘priming’ effect or ANI (added nitrogen interaction) of the applied material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010664
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Effect of the timing and rate of nitrogen fertilization on the growth and recovery of fertilizer nitrogen within the potato (Solanum tuberosum L.) crop (1990)
    Springer
    Nutrient cycling in agroecosystems 21 (1990), S. 133-140 
    Details
    ISSN: 1573-0867
    Keywords: Potatoes ; nitrogen ; foliar sprays ; urea ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of the timing of N fertilizer application on the uptake and partitioning of N within the crop and the yield of tubers has been studied in two experiments. In 1985 either none, 8 or 12 g N m−2 was applied and in 1986 none, 12 or 18 g N m−2. Fertilizer N was applied either at planting, around the time of tuber initiation or half at planting and the remainder in four foliar sprays of urea during tuber bulking.15N-labelled fertilizer was applied to measure the recovery of fertilizer N in the crops. There was an apparent pre-emergence loss of nitrate from the soil when N was applied at planting in 1986, thereby reducing the efficiency of fertilizer use. Applying the N at tuber initiation delayed and reduced the accumulation of N in the canopy compared with crops receiving all their fertilizer at planting. Foliar sprays of urea slightly increased both tuber yields and tuber N contents when compared to a single application at planting. The proportion of the fertilizer N recovered in the crop was little affected by the rate of N application, but a greater proportion of foliar-applied N was recovered than N broadcast at planting, due partly to pre-emergence losses of nitrate in 1986. It is suggested that late applications of N was foliar sprays can be of benefit to crops with a long growing season and reduce environmental losses of N.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01087422
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Soil structural aspects of decomposition of organic matter by micro-organisms (1990)
    Springer
    Biodegradation 11 (1990), S. 213-233 
    Details
    ISSN: 1572-9729
    Keywords: Decomposition ; microbial biomass ; soil architecture ; soil organic matter ; 15N ; 14C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil architecture is the dominant control over microbially mediated decomposition processes in terrestrial ecosystems. Organic matter is physically protected in soil so that large amounts of well-decomposable compounds can be found in the vicinity of largely starving microbial populations. Among the mechanisms proposed to explain the phenomena of physical protection in soil are adsorption of organics on inorganic clay surfaces and entrapment of materials in aggregates or in places inaccessible to microbes. Indirect evidence for the existence of physical protection in soil is provided by the occurrence of a burst of microbial activity and related increased decomposition rates following disruption of soil structures, either by natural processes such as the remoistening of a dried soil or by human activities such as ploughing. In contrast, soil compaction has only little effect on the transformation of 14C-glucose. Another mechanism of control by soil structure and texture on decomposition in terrestrial ecosystems is through their impact on microbial turnover processes. The microbial population is not only the main biological agent of decomposition in soil, it is also an important, albeit small, pool through which most of the organic matter in soil passes. Estimates on the relative importance of different mechanisms controlling decomposition in soil could be derived from results of combined tracer and modelling studies. However, suitable methodology to quantify the relation between soil structure and biological processes as a function of different types and conditions of soils is still lacking.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00004497
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...