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  • nitrogen  (69)
  • Springer  (69)
  • Cell Press
  • 1985-1989  (64)
  • 1980-1984  (5)
  • 1988  (44)
  • 1986  (20)
  • 1981  (5)
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  • Springer  (69)
  • Cell Press
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  • 1985-1989  (64)
  • 1980-1984  (5)
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  • 1
    Digitale Medien
    Digitale Medien
    Nitrogen requirements in young Douglas-fir of the Pacific North-west (1988)
    Springer
    Nutrient cycling in agroecosystems 15 (1988), S. 173-179 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Douglas-fir ; urea ; basal area increment ; growth response ; nitrogen ; critical level
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A series of fourteen Pacific North-west Douglas-fir installations, ranging in age from 6 to 26 years were analysed with respect to site factors, foliage nutrients, and growth response to applied fertilizer. Unfertilized basal area increment ranged from 1.2 to 3.1 m2 ha−1 yr−1 with no apparent relationship with soil, stand age or site index. Basal area increment was correlated with foliage N and a critical level for N was calculated as 1.7%. Applications of 220 kg N ha−1 as urea increased growth between 0 and 95% of the unfertilized basal area growth, with an average of 24.9%. Response could be predicted from foliage N and unfertilized basal area increment. When the same relationships were applied to previously older stand data, results were more variable as elements such as B and S showed evidence of being limiting.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01050679
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  • 2
    Digitale Medien
    Digitale Medien
    Nitrogen and potassium requirement of pineapple in relation to irrigation in Nigeria (1988)
    Springer
    Nutrient cycling in agroecosystems 15 (1988), S. 203-210 
    Details
    ISSN: 1573-0867
    Schlagwort(e): irrigation ; pineapples ; nitrogen ; potassium ; yield ; Nigeria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The investigation studied the effect of fertilization with four nitrogen levels (0, 100, 150 and 200 kg/ha), four potassium levels (0, 100, 150 and 200 kg/ha) and four irrigation treatments (0, 3, 7 and 14-day interval) on the growth and yield of smooth Cayenne pineapples. Increasing irrigation frequency increased growth parameters of number of leaves, D-leaf length and days to 50% flowering. Fruit weight was highest at N = 150 kg/ha, K = 200 kg/ ha and irrigation once a week. Higher N levels (beyond 150 kg/ha) applied after the plant crop has been harvested did not further enhance yields of the ratoon crop. For K = 200 kg/ha potential and harvested yields were reduced in all irrigation treatments when N 〉 150 kg/ha.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01051342
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  • 3
    Digitale Medien
    Digitale Medien
    Fertilizer requirement of rice-wheat and maize-wheat rotations on coarse-textured soils amended with farmyard manure (1988)
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 153-164 
    Details
    ISSN: 1573-0867
    Schlagwort(e): farmyard manure ; maize ; nitrogen ; phosphorus ; rice ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field experiments with rice-wheat rotation were conducted during five consecutive years on a coarse-textured low organic matter soil. By amending the soil with 12t FYM ha−1, the yield of wetland rice in the absence of fertilizers was increased by 32 per cent. Application of 80 kg N ha−1 as urea could increase the grain yield of rice equivalent to 120 kg N ha−1 on the unamended soil. Although the soil under test was low in Olsen's P, rice did not respond to the application of phosphorus on both amended and unamended soils. For producing equivalent grain yield, fertilizer requirement of maize grown on soils amended with 6 and 12 t FYM ha−1 could be reduced, respectively to 50 and 25 per cent of the dose recommended for unamended soil (120 kg N + 26.2 kg P + 25 kg K ha−1). Grain yield of wheat grown after rice on soils amended with FYM was significantly higher than that obtained on unamended soil. In contrast, grain yield of wheat which followed maize did not differ significantly on amended or unamended soils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01050276
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  • 4
    Digitale Medien
    Digitale Medien
    Productivity of nitrogen fertilized plantain in intercropping systems (1988)
    Springer
    Nutrient cycling in agroecosystems 18 (1988), S. 245-250 
    Details
    ISSN: 1573-0867
    Schlagwort(e): plantain ; intercropping systems ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The investigation evaluated the productivity of plantain intercropped with cassava, cocoyam and yam, fertilized annually with 0, 320 and 480 kg N ha−1 respectively. Yields from nitrogen fertilized intercrops were higher than those of unfertilized treatments. In plantain + cassava intercrop receiving 480 kg N ha−1 plantain growth was suppressed. Plantain intercropped with yam and fertilized with 320 kg N ha−1 matured early and produced better bunches than other treatments. Plantain + yam or cocoyam intercropping systems fertilized with 320 kg N ha−1 were recommended because of improved plantain establishment and increased combined crop yields.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01049574
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  • 5
    Digitale Medien
    Digitale Medien
    The role of vibrationally excited nitrogen in the ionosphere (1988)
    Springer
    Pure and applied geophysics 127 (1988), S. 529-544 
    Details
    ISSN: 1420-9136
    Schlagwort(e): Ionosphere ; nitrogen ; vibrational temperatures ; N2 and CO2 and populations of N2 and CO2 in the D, E and F regions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Theoretical and experimental aspects of the production, transformation, diffusion and loss of N2 in the upper atmosphere are considered. The N2-CO2 near-resonant system in theD andE regions is taken into account. We describe our understanding of the methods necessary to find the vibrational populations of N2 and CO2 (asymmetric mode of CO2). The calculations of the vibrational temperatures in theD, E, andF regions for the mid-latitude ionosphere and an aurora are presented. The connection between the excited species and the 4.26-μm radiation intensities is considered. The models for the rate coefficient of the reaction of O+ with N2 and the electron density decrease resulting from N2 in the F region are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00879824
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  • 6
    Digitale Medien
    Digitale Medien
    Biota and abiotic environment in the Westerschelde estuary (1988)
    Springer
    Aquatic ecology 22 (1988), S. 31-34 
    Details
    ISSN: 1573-5125
    Schlagwort(e): estuaries ; tidal mixing ; suspended matter ; sedimentation ; nitrogen ; plankton ; benthos
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An estuary such as the Westerschelde is a highly dynamic environment, both on an ecological time scale where climatic and hydrodynamic forces, mainly the tides, shape a very variable environment and on a geological, evolutionary time scale, since estuaries are young and very unstable habitats. Low species diversity and high adaptability of the resident animal and plant populations are characteristic of estuarine habitats where large fluctuations in submersion, salinity, temperature etc. occur. The existing biota are therefore resilient to environmental stress and effects of the important influx of anorganic and organic pollutants from the river Schelde and its tributaries on the biota in the estuary are not easy to detect. Although water movement and sedimentation patterns in the Westerschelde are relatively well known, there exists little information on important ecological processes such as primary production and heterotrophic metabolism in the estuary.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02256779
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  • 7
    Digitale Medien
    Digitale Medien
    Variation of the amino acid scores and of the nitrogen-to-protein conversion factors in barley grain as a function of nitrogen content as compared with wheat and rye (1988)
    Springer
    Plant foods for human nutrition 38 (1988), S. 175-188 
    Details
    ISSN: 1573-9104
    Schlagwort(e): barley ; Triticeae ; grain ; amino acid composition ; nitrogen ; chemical score
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Barley grains (9 samples from 7 cultivars) with nitrogen contents (N) ranging from 1.45 to 4.01% of dry matter were analysed for their amino acid (AA) composition with high accuracy from six different hydrolysates per sample. AA levels in grain increased as linear functions ofN with correlation coefficients close to unity. A comparison with literature data confirmed that the AA composition of any grain sample of normal barley can be predicted from itsN for all phenotypes and genotypes. AAs in grain protein changed as hyperbolic functions ofN which increased for Phe, Pro and Glx but more or less strongly decreased for the other AAs. By plotting AA scores againstN, barley proteins were shown to be always richer than wheat and rye in Val and Phe + Tyr; sometimes richer than both other species forN〈2 (Lys); 2.2 (Leu and Ile); 3.4 (Thr); sometimes intermediate to wheat and rye above the latterN values. They were also intermediate in sulphur AAs forN〈1.9 and drastically poorer forN〉1.9. However, they were richer than both other species in Trp forN〉1.6. The hyperbolic variations of non-protein nitrogen and nitrogen-to-protein conversion factors were determined as a function ofN and also compared with those of wheat and rye.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01091722
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  • 8
    Digitale Medien
    Digitale Medien
    Nitrogen mineralization ofSesbania sesban used as green manure for lowland rice in Sri Lanka (1988)
    Springer
    Plant and soil 108 (1988), S. 201-209 
    Details
    ISSN: 1573-5036
    Schlagwort(e): decomposition ; green manure ; litterbag ; nitrogen ; paddy rice ; Sesbania sesban ; Sri Lanka
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Sesbania sesban was evaluated as green manure crop for lowland rice in the Dry Zone of Sri Lanka. The legume was grown during a fallow period before lowland rice (Oryza sativa) and ploughed under just before transplanting. Weight loss and nitrogen content in litterbags containing leaves, stems and roots of the legume were monitored. Comparisons were made between rice yields from 20 m2 plots after green manuring in combination with different nitrogen fertilizer levels (0, 2.4, 4.8 and 7.2 gm−2) and nitrogen fertilizer (9.6 gm−2) alone. Above-ground biomass ofS. sesban was 440 gm−2 (dry wt) when ploughed under after 84 days growth. N-content in leaves, stems and roots was 3.76%, 0.41% and 0.73%, respectively. This gave a N-input fromS. sesban of 9.2 gm−2 (8.3 g from above-ground parts and 0.9 g from roots). The corresponding K and P inputs were 7.3 and 0.6 gm−2 respectively. The nitrogen rich leaves, which contained 88% of the nitrogen in the above-ground parts, decomposed and released its nitrogen much more rapidly than the stems and roots. After only four days the leaves had released 5.3 g Nm−2 and after 14 days they had released 6.4 g Nm−2. The highest rice yield (505 gm−2) was obtained usingS. sesban and 4.8 gm−2 of N-fertilizer. The yields with only N-fertilizer or onlyS. sesban were 442 gm−2 and 396 gm−2, respectively. Due to the rapid decomposition of the nitrogen rich leaves,S. sesban did not behave as a slow release fertilizer. Thus, it is not necessary to apply nitrogen fertilizers as a basal dose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02375650
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  • 9
    Digitale Medien
    Digitale Medien
    C, N, and S mineralization of crop residues as influenced by crop species and nutrient regime (1988)
    Springer
    Plant and soil 106 (1988), S. 35-41 
    Details
    ISSN: 1573-5036
    Schlagwort(e): carbon ; crop residue ; mineralization ; nitrogen ; organic matter ; sulfur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The mineralization of C, N, and S from residues of three different crop species (wheat, lentil, and rape) grown under diverse nutritional regimes was measured over a 12-week incubation period under controlled conditions. The rate of decomposition, as measured by CO2 evolution, varied considerably among treatments and appeared to be controlled almost entirely by N content of the residue (R2=0.98). Similarly, N mineralization was strongly tied to N concentration. The critical N concentration, below which significant immobilization of N occurred, declined over time, ranging from 1.9% at day 14 to 1.1% at day 84. Mineralization of S was positively correlated with initial S concentration (R2=0.95) and negatively related to N concentration, apparently because of a dilution effect. The results demonstrate that decomposition and N and S mineralization of crop residues, under conditions prevalent in the experiment, are primarily a function of their nutrient concentrations rather than biochemial composition related to crop species. As a result, it should be possible to enhance rate of residue decomposition, increase quantities of N and S mineralized, and avert detrimental immobilization losses in the following year by governing the nutritional regime under which the crop is grown.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02371192
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  • 10
    Digitale Medien
    Digitale Medien
    Lignin and nitrogen in the decomposition of leaf litter in a sub-tropical forest ecosystem at Shiroy hills in north-eastern India (1988)
    Springer
    Plant and soil 106 (1988), S. 59-64 
    Details
    ISSN: 1573-5036
    Schlagwort(e): decomposition ; lignin ; litter ; nitrogen ; sub-tropical-forest
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of the initial lignin and nitrogen contents of the leaves of five tree species, on their decomposition dynamics, was studied in the sub-tropical forest ecosystem existing at Shiroy hills. The decomposition dynamics of litter materials are described by inverse linear relationships between the percentage of the original biomass remaining and the nitrogen concentration in the residual material. Initial lignin and nitrogen were highly correlated with remaining biomass (r=0.94 and 0.77). The rate constants (K), for the annual leaf mass loss, ranged from −0.18 to −0.56. The values for initial lignin (%), initial nitrogen (%), the ratio between initial lignin, initial nitrogen and the annual decomposition rate constants were compared with similar results from other studies in various climatic zones of the world.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02371195
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  • 11
    Digitale Medien
    Digitale Medien
    The use of ion-exchange resin bags for measuring nutrient availability in an arid ecosystem (1988)
    Springer
    Plant and soil 105 (1988), S. 105-111 
    Details
    ISSN: 1573-5036
    Schlagwort(e): chronosequence ; desert ; ion-exchange resins ; mineralization ; nitrogen ; nutrient availability ; phosphorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Anin situ resin bag technique was used to measure the relative availabilities of N and P along a chronosequence of soils in southern New Mexico, and was compared to two more common indices of nutrient availability. Accumulations of N and P during 10-week intervals over an 18 month period were separable into wet season (September–January) and dry season (February–August) groups, with wet season values significantly greater than dry season values. Only accumulations during the wet season showed significant differences among sites, thus stressing the role of field water regime in interpreting resin accumulation results. Total mineral N (NO3+NH4) sorbed by resins was significantly correlated to laboratory N mineralization rates. Although accumulation patterns of N and P were similar to patterns of %N and %P in shrub species growing along the chronosequence, these similarities were not statistically significant. A laboratory experiment demonstrated that bicarbonate-form anion resins are preferable to hydroxyl-form resins, as long as standards are made from solutions extracted by resins to account for variable ion recovery efficiencies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02371147
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  • 12
    Digitale Medien
    Digitale Medien
    Transformations of carbon and nitrogen in a Calciorthid soil amended with a range of organic residues (1988)
    Springer
    Plant and soil 105 (1988), S. 205-212 
    Details
    ISSN: 1573-5036
    Schlagwort(e): extractable carbon ; fulvic acids ; humic acids ; humification ; mineralization ; nitrogen ; oxidizable carbon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A calcareous soil was treated with an organic fertilizer mixture of grape debris and peat, or with pig manure, chicken manure, city refuse or with aerobic or anaerobic sewage sludges. Changes in different fractions of carbon and nitrogen were followed by analysis of the soil, immediately after these additions, after they had decomposed for six months in the soil, after a maize harvest, and after a subsequent barley harvest. The various forms of carbon had decreased after six months. The rate of decrease varied with the nature of the organic materials. In all samples, the fulvic acids fraction decreased most. The main transformations happened during the first six months whether there was a crop growing or not, but the crops had no influence on the breakdown of the organic materials. The ratio of humic acids/fulvic acids had increased after six months of humification and, in general terms, the final values of the ratio oxidizable carbon/extractable carbon were lower than the initial ones, indicating a higher degree of humification in the organic matter by the end of the experiment. The total nitrogen level remained practically constant after the first six months of humification even after the second crop. Part of the organic nitrogen of the soil samples amended with chicken manure, city refuse or the two sludges was transformed into mineral nitrogen during the humification process. The extractable nitrogen values increased because of the fertilizer applied during the pot trials.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02376784
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  • 13
    Digitale Medien
    Digitale Medien
    The effectiveness of some Indonesian strains of Rhizobium on four tropical legumes (1988)
    Springer
    Plant and soil 108 (1988), S. 171-177 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Legume growth ; nitrogen ; nodulation ; Rhizobium strains
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nodules were collected from 14 legume species from the Indonesian Islands of South Sulawesi, Java and Sumatra. Their rhizobia were isolated and growth characteristics, nodulation ability and nitrogen fixing effectiveness were assessed against recommended commercially available Australian strains. The test legumes wereMacroptilium atropurpureum Urb. cv. Siratro,Vigna unguiculata (L.) Walp. cv Eureka,Centrosema pubescens Benth cv. Belalto andDesmodium heterocarpon (L) DC. A significant portion of the native rhizobial isolates were of the fast growing type. Dry matter and total nitrogen production forM. atropurpureum andV. unguiculata was highest when inoculated with native strains while the commerical strains produced superior dry matter production forC. pubescens andD. heterocarpon. However the total nitrogen production of native and commercial strains was not significantly different for the latter two legumes. The study indicated that a potential exists for developing inocula from local Rhizobium strains.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02370112
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  • 14
    Digitale Medien
    Digitale Medien
    Vesicular-arbuscular mycorrhizal infection of lucerne roots in a cellulose-amended soil (1988)
    Springer
    Plant and soil 112 (1988), S. 99-104 
    Details
    ISSN: 1573-5036
    Schlagwort(e): biological control ; cellulose ; nitrogen ; VAM fungi ; VAM symbiosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Lucerne plants inoculated with vesicular-arbuscular mycorrhizal fungi were grown in pots in a sandy soil amended or not amended with cellulose. Whatever the endophyte or cellulose sources used, the rate of VAM colonization was lower in amended soil. The inhibition of VAM infection increased with the cellulose concentration in the soil. Sequential harvest experiments showed a clear reduction of root colonization from the early stages of plant growth. The effectiveness of cellulose in reducing VAM colonization was influenced by the addition of N fertilizer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02181758
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  • 15
    Digitale Medien
    Digitale Medien
    Effects of root pruning of wheat at different nitrogen levels (1988)
    Springer
    Plant and soil 109 (1988), S. 128-130 
    Details
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; root pruning ; shoot ; root ratio ; Thornley's model ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In two experiments, wheat plants growing in solutions of different nitrogen concentration were subjected to root pruning. In higher concentrations of nitrogen the growth rate was higher, and the proportional allocation of growth to shoot higher, but pruning did not affect the allocation of growth at either level of nitrogen. This result gives no support to Thornley's source-sink model of the control of shoot: root ratio.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02197591
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  • 16
    Digitale Medien
    Digitale Medien
    Rice straw decomposition in rice-field soil (1988)
    Springer
    Plant and soil 109 (1988), S. 145-146 
    Details
    ISSN: 1573-5036
    Schlagwort(e): biomass ; carbon ; decomposition ; nitrogen ; phosphorus ; rice straw
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Rice straw, buried in a rice-field during the dry season decomposed at a rate of 0.0075 day-1. Seventy five percent of the biomass, 70 percent carbon, 50 percent nitrogen and 30 percent phosphorus remained after 139 days of decomposition. Rice straw decomposition furnished 33% N and 8% P of the total nitrogen and phosphorus provided by man.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02197596
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  • 17
    Digitale Medien
    Digitale Medien
    Derivation of critical nutrient concentrations for growth rate from data from field experiments (1988)
    Springer
    Plant and soil 109 (1988), S. 159-169 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Brassica oleracea vargemmifera ; Brussels sprout ; model ; nitrate ; nitrogen ; sap ; simulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Present methods for determining critical nutrient concentrations in plants and soils are unsatisfactory if concentrations change with time while the crop is growing. In such cases the critical concentration can only be applied in relation to growth rate at any given moment. For interpreting field experiments this introduces considerable difficulties: two possible approaches to these problems are suggested, one of which uses a simple simulation model. Results from a Brussels sprout nitrogen experiment are used to show how, using this approach, a single critical sap nitrate concentration (380 mg NO3 N.l−1 for 95% of potential growth rate) may serve to explain the results at all growth stages in three seasons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02202080
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  • 18
    Digitale Medien
    Digitale Medien
    A microcosm study of nitrogen utilization in the Great Salt Lake, Utah (1988)
    Springer
    Hydrobiologia 158 (1988), S. 89-100 
    Details
    ISSN: 1573-5117
    Schlagwort(e): halophiles ; hypersalinity ; Great Salt Lake ; microcosm ; nitrogen ; ecology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Microcosms were used to study the effects of two inorganic nitrogen sources (ammonia and nitrate) and two organic nitrogen sources (urea and glutamic acid) on the growth of algae and bacteria found in the Great Salt Lake, Utah. Ammonia, nitrate and urea stimulated bacterial growth indirectly through increased algal production of unknown organic substances. Glutamic acid, representing readily available organic carbon and nitrogen, stimulated the bacteria directly. No nitrification was observed in the microcosms although nitrite was found when the microcosms were supplemented with nitrate. Lake sediment contained a number of anaerobic bacteria producing hydrogen sulfide, methane and other gases. Production of these gases was stimulated in the columns with high algal and bacterial activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026268
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  • 19
    Digitale Medien
    Digitale Medien
    Nutrient-phytoplankton relationships in a tropical meromictic soda lake (1988)
    Springer
    Hydrobiologia 158 (1988), S. 15-28 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Nutrients ; phosphorus ; nitrogen ; phytoplankton ; Lake Sonachi ; Kenya
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Seasonal variation through one year in total nitrogen (TN), total phosphorus (TP), phytoplankton biomass, phytoplankton species composition and other environmental factors were examined in Lake Sonachi, a tropical meromictic soda lake. Mean concentrations of TN and TP were 11 000 µg N l-1 and 100 µg P l-1, respectively. Maximum concentrations of TN and TP occurred in the monimolimnion. Phytoplankton biomass ranged from 350 to 1260 mg m-3. Synechococcus bacillaris, a small coccoid cyanophyte, dominated the phytoplankton. The mean chlorophyll a concentration of 37 mg · m-3 was a modest value when compared with those of other tropical soda lakes. High TN:TP ratios indicated phosphorus limitation in the lake.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026265
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  • 20
    Digitale Medien
    Digitale Medien
    Evaluation of indicators of nitrogen limitation in deep prairie lakes with laboratory bioassays and limnocorrals (1988)
    Springer
    Hydrobiologia 159 (1988), S. 269-276 
    Details
    ISSN: 1573-5117
    Schlagwort(e): blue-green algae ; prairie lakes ; limnocorrals ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The deep lakes in central Alberta are characterized by relatively high total nitrogen (TN) to total phosphorus (TP) ratios (33 to 64, by weight) and high TP (10 to 100 µg 1−1) in the euphotic zone in summer. These same lakes show indications of nitrogen limitation: (1) blue-green algae are relatively important in summer (7 to 88% of total biomass) and a large proportion of the filaments contain heterocysts and (2) inorganic nitrogen levels are extremely low in the surface waters (NO inf2 sup− + NO inf3 sup− + NH inf4 sup+ − N 〈 10 µg 1−1). In 1985 and 1986 inorganic nitrogen (25 to 1200 µg 1−1 − N) and/or phosphorus (12 to 100 µg 1−1 − P) was added to water in 31 m3 limnocorrals or 21 bottles from four deep prairie lakes. In most cases, phytoplankton biomass (estimated as chlorophyll a) was stimulated only by phosphorus additions. However, for a short period (8 d) after an unusual storm, phytoplankton biomass was stimulated by nitrogen additions. After this storm, TP increased by up to 75% in the epilimnion of the study lakes whereas TN did not increase. The algae which increased in these experiments tended to be the dominant algae in the control vessels, which varied with the experiment and the lake. Thus, a large proportion of blue-green algae and low inorganic nitrogen levels are not indicative per se of nitrogen limitation in lakes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008240
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  • 21
    Digitale Medien
    Digitale Medien
    Factors influencing nitrate depletion in a rural stream (1988)
    Springer
    Hydrobiologia 160 (1988), S. 111-122 
    Details
    ISSN: 1573-5117
    Schlagwort(e): denitrification ; mass balance ; nitrogen ; streams ; water residence time ; water temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A mass balance procedure was used to analyze rates of nitrate depletion in three adjacent reaches of West Duffin Creek, Ontario, Canada. Daily nitrate losses in individual reaches were highly variable (0.5–24 kg N) during low and moderate stream flows in May–October, 1982–1985. Nitrate removal efficiency (nitrate loss as a % of nitrate input) showed a rapid exponential decline with increased nitrate inputs to each reach. Nitrate losses and nitrate removal efficiency also had a significant negative correlation with stream discharge. The association of large nitrate loads with high stream discharge reduced the nitrate removal capacity of the stream because of shorter residence times and a higher ratio of water volume to stream bed area. Water temperature exhibited a significant positive correlation with nitrate loss which may reflect increased denitrification at higher temperatures. Variations in nitrate losses and nitrate removal efficiency between the three reaches were highly influenced by differences in water residence time. Standarized nitrate losses with respect to water residence time revealed a longitudinal decline in nitrate depletion between the reaches which was associated with a downstream decrease in stream nitrate concentration and in the organic carbon content of fine textured sediments from pool habitats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00015474
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  • 22
    Digitale Medien
    Digitale Medien
    Growth regulation of Scots pine seedlings with different fertilizer compositions and regimes (1988)
    Springer
    New forests 2 (1988), S. 119-130 
    Details
    ISSN: 1573-5095
    Schlagwort(e): Pinus sylvestris ; fertilization ; nitrogen ; potassium ; phosphorus ; outplanting performance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Scots pine (Pinus sylvestris L.) seedlings were grown in containers filled with peat, using two different fertilizers and three different fertilizer regimes. Seedling shoot and root growth and shoot content of nitrogen, potassium and phosphorus were followed in the nursery and after outplanting in the field. Attempts to regulate growth rate by an exponential nutrient supply were not successful, but the root/shoot ratio was influenced by the fertilization regime. Internal nitrogen concentration was stable only for seedlings with low relative growth rate, while seedlings with high nutrient supply in the nursery showed strong nutrient dilution in the shoot after planting.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027763
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  • 23
    Digitale Medien
    Digitale Medien
    Response of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to some different fertilizers applied at planting (1988)
    Springer
    New forests 2 (1988), S. 89-110 
    Details
    ISSN: 1573-5095
    Schlagwort(e): slow release fertilizers ; nitrogen ; phosphorus ; nutrient uptake ; planting stock ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Four fertilization at planting experiments were conducted with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) on eastern Vancouver Island. In experiment 1 Agriform (20-10-5, AGR) and Osmocote (17-7-12, OSM) supplied N at 0, 4.2, 8.4, 16.8 or 33.6 g/tree either broadcast, within 15 cm of the tree, or in a hole 15 cm from the tree (adjacent). In experiment 2 AGR, diammonium phosphate (21-55-0, DAP), ammonium sulphate (21-0-0, AMS), sulphur coated urea (35-0-0, SCU) supplied N at 0, 8.4, 16.8 and 25.2 g/tree. Triple superphosphate (0-45-0, TSP) supplied P at the same levels as DAP: 0, 9.6, 19.2 and 28.8 g/tree. In experiment 3 AGR and SCU (32-0-0) supplied N at 0, 8.4 and 16.8 g/tree. In experiment 4 DAP was used to fertilize trees on five different dates, between March and October, and each treatment supplied 16 g N/tree. Two-year old, bare root, planting stock was used except in experiment 3, where container stock was compared with bare root stock. Little growth response was obtained after one year, but height growth responses of 12 to 31% were measured after 3 to 6 years with fertilizers supply 8.4 to 16.8 g N per tree. Growth responses were little affected by the type of fertilizer and were primarily due to N, with release rate having no marked effect. The exception to this was TSP which did not increase growth but did increase survival. Survival was reduced by AMS and to a lesser extent by AGR. Container seedlings responded more to fertilization at planting than bare root seedlings. Seedling N, P and K concentrations and contents declined following planting for 6 months and only started to recover after July. Application of fertilizer caused a small increase in seedling nutrient concentration regardless of date, but this had no detectable effect on dry weight measured six weeks later.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027761
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  • 24
    Digitale Medien
    Digitale Medien
    Ecology of deepwater rice-fields in Bangladesh 5. Mineral composition of the rice plant and other aquatic macrophytes (1988)
    Springer
    Hydrobiologia 169 (1988), S. 57-67 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Mineral composition ; nitrogen ; phosphorus ; aquatic macrophyte ; deepwater rice ; Meghna ; Azolla pinnata ; Eichhornia ; Alternanthera phyloxeroides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mineral composition of deepwater rice (cultivar Kartik Sail) was studied during 1986 in a field near Sonargaon, Bangladesh, which is flooded by water from R. Meghna. Samples were taken four times, once prior to flooding and three times during the flood season. On two of the latter days (10 August = end of first flood peak, 23 September = second flood peak) the study was extended to other components of the ecosystem (sediments + soil, water, other aquatic macrophytes). On 23 September, 32% of the mass of the plant was out of water, 65% in water and 3% in sediment/soil. There were marked differences between elements in their pattern of accumulation by deepwater rice through the season. In comparison with the final totals for each element, about 48% of N, but only 11% of P and 10% of Na had been accumulated by the time the floodwater had arrived. The aquatic roots doubled in mass between the times of the two flood peaks and it is suggested that much of the P taken up by the plant may reach the plant via its aquatic roots after having becoming mobilized and released to the water when sediments become anaerobic. In comparison with other parts of the plant, Na was always much higher in the stem and Zn in the basal roots. Other aquatic macrophytes (‘weeds’) increased from 0.40% of the mass (dry weight) of deepwater rice on 10 August to 4.0% on 23 September. However their content of each element (% dry weight) was considerably higher than that in deepwater rice, so they may at times compete effectively with the rice for nutrients. During the flood period (to 23 September) weeds accumulated 16% of the N accumulated by rice during the same period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00007933
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  • 25
    Digitale Medien
    Digitale Medien
    Dynamics of C, N, P and S in grassland soils: a model (1988)
    Springer
    Biogeochemistry 5 (1988), S. 109-131 
    Details
    ISSN: 1573-515X
    Schlagwort(e): soil organic matter ; nitrogen ; phosphorus ; sulfur ; simulation ; grasslands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract We have developed a model to simulate the dynamics of C, N, P, and S in cultivated and uncultivated grassland soils. The model uses a monthly time step and can simulate the dynamics of soil organic matter over long time periods (100 to 10,000 years). It was used to simulate the impact of cultivation (100 years) on soil organic matter dynamics, nutrient mineralization, and plant production and to simulate soil formation during a 10,000 year run. The model was validated by comparing the simulated impact of cultivation on soil organic matter C, N, P, and S dynamics with observed data from sites in the northern Great Plains. The model correctly predicted that N and P are the primary limiting nutrients for plant production and simulated the response of the system to inorganic N, P, and S fertilizer. Simulation results indicate that controlling the C:P and C:S ratios of soil organic matter fractions as functions of the labile P and S levels respectively, allows the model to correctly simulate the observed changes in C:P and C:S ratios in the soil and to simulate the impact of varying the labile P and S levels on soil P and S net mineralization rates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02180320
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  • 26
    Digitale Medien
    Digitale Medien
    Nutrient uptake by barley roots under field conditions (1988)
    Springer
    Plant and soil 109 (1988), S. 171-179 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Black Solod ; inflow ; magnesium ; nitrogen ; phosphorus ; potassium ; root efficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field study with barley was conducted in 1984 and 1985 to provide data on uptake rates of N, P, K and Mg and their variation as the growing season progressed. Two varieties were grown: Galt in 1984 and Otal in 1985. Soil fertility was maintained at or near optimum conditions. Samples were obtained approximately every 10 days for shoot dry weight, nutrient content and root length measurements. The approximate method (Williams, 1948) traditionally used for calculating uptake rates was found to be invalid for most of the nutrients studied. The method used for measuring uptake rates was the functional approach proposed by Hunt (1973). Inflow,i.e. uptake rate per unit root length, of plant nutrients, decreased with time. However, maximum uptake rates measured in kg ha−1d−1 occurred at about 50 days from sowing because of increasing root length density with time. Inflow or uptake rates were low in 1985 because of moisture deficiency, and grain yield (0.89 t ha−1) was severely depressed. This study demonstrated that Hunt's method is superior and more advantageous than the traditional, approximate method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02202081
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  • 27
    Digitale Medien
    Digitale Medien
    Nitrogen fixation, transfer and turnover in upland and lowland grass-clover swards, using15N isotope dilution (1988)
    Springer
    Plant and soil 112 (1988), S. 247-254 
    Details
    ISSN: 1573-5036
    Schlagwort(e): isotope dilution ; 15N ; nitrogen ; nitrogen fixation ; nitrogen transfer ; ryegrass ; white clover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The stable isotope15N is particularly valuable in the field for measuring N fixation by isotope dilution. At the same time other soil-plant processes can be studied, including15N recovery, and nitrogen transfer between clover and grass. Three contrasting sites and soils were used in the present work: a lowland soil, an upland soil, and an upland peat. Nitrogen fixation varied from 12 gm−2 on lowland soil to 2.7 gm−2 on upland peat. Most N transfer occurred on upland soil (4.2 gm−2) which, added to nitrogen fixed, made a total of 8.7 gm2 input during summer 1985.15N recovery for the whole experiment was small, around 25%. Measurement of dead and dying leaves, stubble and roots, suggests that plant organ death is the first stage in N transfer from white clover to ryegrass, through the decomposer cycle. Decomposition was fastest on lowland soils, slowest on peat. On lowland soil this decomposer nitrogen is apparently subverted before transfer, probably by soil microbes. Variations in natural abundance of15N in plants were found in the two species on the different soils. These might be used to measure nitrogen fixation without adding isotope, but the need for many replicates and repeat samples would limit throughput.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02140002
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  • 28
    Digitale Medien
    Digitale Medien
    The response ofPlantago lanceolata L. andP. major L. spp.major to nitrate depletion (1988)
    Springer
    Plant and soil 107 (1988), S. 197-206 
    Details
    ISSN: 1573-5036
    Schlagwort(e): nitrate ; nitrate reductase activity ; nitrogen ; nitrogen use efficiency ; osmotic solutes ; Plantago lanceolata ; Plantago major ; redistribution ; sugars
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract To study aspects of the ecology of grassland species, in a comparative experiment, plants ofP. lanceolata andP. major were grown in pots in a greenhouse, and subjected to a gradual nitrate depletion for several weeks. Control plants were weekly supplied with nitrate. Growth, leaf appearance and disappearance, concentrations of cations and inorganic anions, soluble and insoluble reduced nitrogen concentrations,in vivo nitrate reductase activity (NRA) and the concentration of non-structural carbohydrates in several parts of the plants were followed. Depletion of nitrate caused a reduction of shoot growth, both in biomass and number of leaves. Withering of leaves increased. Accumulation of root dry matter was little (P. lanceolata), or not (P. major) affected. The concentration of reduced nitrogen in all tissues also decreased, both that of the soluble and that of the insoluble fraction. As a result, nitrogen use efficiency (NUE, g dry matter produced per mmol N incorporated) increased by nitrate depletion. NRA was higher in the roots than in the leaves, and decreased with increasing nitrate depletion. In control plants, nitrate became also limiting. This resulted in decreasing nitrate concentrations in leaves and roots. In the leaves, the decrease in nitrate concentration was preceded by a decrease in NRA. The decrease of the nitrate concentration was parallelled by an increase in the concentration of soluble sugar. No major differences in the response towards nitrate depletion were observed between the two species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02370547
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  • 29
    Digitale Medien
    Digitale Medien
    Plant and soil nitrogen dynamics in California annual grassland (1988)
    Springer
    Plant and soil 110 (1988), S. 9-17 
    Details
    ISSN: 1573-5036
    Schlagwort(e): grassland ; Mediterranean ; microbial biomass ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Seasonal changes in soil water and nitrogen availability were related to the phenology and growth of plants in California annual grassland. Plant accumulation of nitrogen was mainly confined to two short periods of the year: fall and early spring. At these times, plants were in the vegetative growth phase, roots were growing rapidly and soil moisture was high. During these periods, soil nitrate was low or depleted. High flux of nitrogen in this ecosystem, however, is indicated by the rapid disappearance of the previous year's detrital material, high microbial biomass, and high mineralizable nitrogen and nitrification potential. At the end of the summer drought, significant amounts of the previous year's detrital material had disappeared, chloroform-labile N (expressed as microbial biomass N) was at its seasonal maximum, and soil inorganic nitrogen pools were high. This suggests inorganic nitrogen flux during the drought period. The ‘drought escaper’ life history characteristics of annual grasses in California annual grassland, however, may prevent plants from utilizing available nitrogen during a large part of the year.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02143533
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  • 30
    Digitale Medien
    Digitale Medien
    Nutrient release from decomposing foliar litter of three tree species with spicial reference to calcium, magnesium and potassium dynamics (1988)
    Springer
    Plant and soil 110 (1988), S. 49-55 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Acer rubrum ; calcium ; cations ; Cornus florida ; decomposition ; litter ; magnesium ; nitrogen ; nutrient release ; phosphorous ; potassium ; Quercus prinus ; sulfur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Calcium, magnesium and potassium dynamics in decomposing litter of three tree species were measured over a two-year period. The speices studied were flowering dogwood (Cornus florida), red maple (Acer rubrum) and chestnut oak (Quercus prinus). The order of decomposition was:C. florida〉A. rubrum〉Q. prinus. Calcium concentrations increased following any initial leaching losses. However, there were net releases of Ca from all three litter types since mass loss exceeded the increases in concentration. Net release of Ca by the end of two years from all three species combined was 42% of initial inputs in litterfall. Magnesium concentrations increased in the second year, following decreases due to leaching during the first year inC. florida andA. rubrum litter. Net release of Mg by the end of two years was 58% of initial inputs. Potassium concentrations decreased rapidly and continued to decline throughout the study. Net release of K by the end of two years was 91% of initial inputs. These data on cation dynamics, and similar data on N, S and P dynamics from a previous study, were combined with annual litterfall data to estimate the release of selected nutrients from foliar litter of these tree species at the end of one and two years of decomposition. The relative mobility of all six elements examined in relation to mass loss after two years was; K〉Mg〉mass〉Ca〉S〉P〉N.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02143538
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  • 31
    Digitale Medien
    Digitale Medien
    Estimation of residual N effect of faba bean and pea on two succeeding cereals using15N methodology (1988)
    Springer
    Plant and soil 110 (1988), S. 81-89 
    Details
    ISSN: 1573-5036
    Schlagwort(e): isotope dilution method ; 15N ; N2 fixation ; nitrogen ; Pisum sativum ; residue ; rhizobium ; Vicia faba L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment was conducted using15N methodology to study the effect of cultivation of faba bean (Vicia faba L.), pea (Pisum sativum L.) and barley (Hordeum vulgare L.) on the N status of soil and their residual N effect on two succeeding cereals (sorghum (Sorghum vulgare) followed by barley). Faba bean, pea and barley took up 29.6, 34.5 and 53.0 kg N ha−1 from the soil, but returned to soil through roots only 11.3, 10.8 and 5.7 kg N ha−1, respectively. Hence, removal of faba bean, pea and barley straw resulted in a N-balance of about −18, −24, and −47 kg ha−1 respectively. A soil nitrogen conserving effect was observed following the cultivation of faba bean and pea compared to barley which was of the order of 23 and 18 kg N ha−1, respectively. Cultivation of legumes resulted in a significantly higher AN value of the soil compared to barley. However, the AN of the soil following fallow was significantly higher than following legumes, implying that the cultivation of the legumes had depleted the soil less than barley but had not added to the soil N compared to the fallow. The beneficial effect of legume cropping also was reflected in the N yield and dry matter production of the succeeding crops. Cultivation of legumes led to a greater exploitation of soil N by the succeeding crops. Hence, appreciable yield increases observed in the succeeding crops following legumes compared to cereal were due to a N-conserving effect, carry-over of N from the legume residue and to greater uptake of soil N by the succeeding crops when previously cropped to legumes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02143543
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  • 32
    Digitale Medien
    Digitale Medien
    Influence of hydrological fluctuations on the growth and nutrient dynamics ofPhalaris arundinacea L. in a riparian environment (1988)
    Springer
    Plant and soil 112 (1988), S. 53-60 
    Details
    ISSN: 1573-5036
    Schlagwort(e): carbon ; flood plain ; macrophytes ; nitrogen ; nutrient cycling ; Phalaris arundinacea ; phosphorus ; potassium ; wate table
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Seasonal changes in aboveground and belowground tissues ofPhalaris arundinacea L. were studied in a population colonizing an ancient meander of the Garonne river (France) submitted to important fluctuations of the permanent water table. Waterlogged conditions in spring stopped the growth of rhizomes and promoted the translocation of nutrient to the shoots. The early senescence of plants after flowering could be related to the withdrawal of the water table. It was characterized by a distribution of nutrients in belowground tissues and a release in litter and soil. Aerated conditions in late summer permitted the growth of belowground tissues. At this time a partition of resources between aboveground and belowground biomass of a new generation of plants was observed. Rising water and decreasing temperatures in winter induced the death of aboveground parts. Reconstitution of nutrient stocks in rhizomes and losses by leaching then occured. Beside a very high primary production this strategy confers toPhalaris arundinacea a great interest in different uses, especially in the removal of nutrients from water in riparian zones as in artificial sites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02181752
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  • 33
    Digitale Medien
    Digitale Medien
    Response surface analysis of the effects of seeding rates, N-rates and irrigation frequencies on durum wheat I. Grain yield and yield components (1988)
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 197-218 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Durum ; grain yield ; irrigation ; modoc ; nitrogen ; response surface model ; seeding rate ; Triticum turgidum ; yield components
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Interactive effects of nitrogen (N) rates, seeding (S) rates and irrigation frequencies on grain yield and yield components of durum wheat were studied for four years under field conditions at Tulelake, California. Each year the experiment was conducted using a split-plot design with 4 irrigation frequencies as main plots and combinations of 5 N-rates (0 to 360 kg/ha) and 5 S-rates (50 to 250 kg/ha) as subplot treatments replicated 4 times. A quadratic response surface model (RSM) was used to study the effects of these treatments on grain yield and yield components (tillers/area, kernel number/spike, kernel weight/spike and 100-seed weight). The RSM was very effective for analysis and data reduction for estimating the optimum combinations of N and S for maximizing the grain yield and yield components. The N utilization and uptake efficiency increased with each irrigation treatment and peaked at irrigation treatment C. Both N and uptake utilization efficiency decreased with each increment of N-rate. In most cases, the effect of irrigation was independent of N and S. One irrigation at tillering increased grain yield and yield components significantly over only a preplant irrigation. The response of additional irrigations were comparatively small and significant only in some cases. Both N and S had significant effects on grain yield and yield components, however, the response of N was larger than that of S. With increasing N-rate, grain yield and tiller number increased with the expected peak beyond 360kg N ha−1 but the increments beyond 180 kg N ha−1 were of progressively smaller magnitude. The kernel number and kernel weight per spike also increased with N-rate giving a peak between 270 and 360 kg N ha−1. With increasing S grain yield and tiller number/area increased while kernel number and kernel weight per spike decreased progressively. It was impossible to maximize yield and yield components at a given combination of N, S, and irrigation. According to the model, grain yield and tiller number were maximized at the highest level of N and S, while kernel number and kernel weight/spike were maximized at the lowest S (50 kg ha−1) and about 314 kg N ha−1 under adequate water supply. On the basis of the findings of this study and output of the model, 180–360 kg N ha−1, 150–250 kg S ha−1 and two post-sowing irrigations (at tillering and at boot stage) in addition to a preplant irrigation was recommended for optimum yield. An additional irrigation might be required depending on the weather conditions during the grain filling period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01049578
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  • 34
    Digitale Medien
    Digitale Medien
    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica II. Cacao and wood production, litter production and decomposition (1988)
    Springer
    Agroforestry systems 6 (1988), S. 37-48 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium ; litter production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract During 7 years (1979–1985) cacao harvests (beans and husks) have been recorded for the agroforestry systems ofTheobroma cacao underCordia alliodora andErythrina poeppigiana shade trees. The mean oven dry cacao yields were 626 and 712 kg.ha−1.a−1 cocoa beans underC. alliodora andE. poeppigiana respectively. Harvests have gradually increased over the years and the plantation has now reached maturity. Annual extraction of N, P, K, Ca and Mg in fruits, which is relatively small, was calculated on the basis of chemical analyses. The following average values were found (kg.ha−1.a−1): At the age of 8 years, theC. alliodora trees have reached 26.7 cm diameter (DBH) and 14.0 m in height. Mean annual growth (from age 5 to 7) is 14.6 m3.ha−1.a−1. Natural plant residue production has been measured for 4 years (Nov. 1981–Oct. 1985). UnderE. poeppigiana it has reached a value of 8.91 t.ha−1.a−1 and underC. alliodora 7.07 t.ha−1.a−1. The shade trees have contributed 57 and 47% respectively. Transference and decomposition rates are high and important in the nutrient cycles. The nutrient content of the litter was analysed and corresponding average yearly transfers were (kg.ha−1.a−1):
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02344744
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  • 35
    Digitale Medien
    Digitale Medien
    The thermal conductivity of pure nitrogen and of mixtures of nitrogen and carbon dioxide at elevated temperatures and pressures (1988)
    Springer
    International journal of thermophysics 9 (1988), S. 3-19 
    Details
    ISSN: 1572-9567
    Schlagwort(e): carbon dioxide ; high pressures ; mixtures ; nitrogen ; thermal conductivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The thermal conductivities of nitrogen at 470 K and six mixtures of nitrogen and carbon dioxide at various temperatures have been measured as a function of pressure up to 25 MPa. The mixtures were measured at the following temperatures: one at 302 K, three at 380 K, one at 430 K, and one at 470 K. The data were used to test three prediction methods for the thermal conductivity of gas mixtures under pressure. Surprisingly good agreement was found with predictions using the corresponding-states method of Ely and Hanley. The predictions of the more theoretically based method of Mason et al. were low throughout, due partly to its use of the Hirschfelder-Eucken equation as the low-density limit, but also because the predicted density dependence rises too slowly. The simplified version of this method proposed by Svojskij gave slightly worse predictions, particularly at higher densities. The zero- density results for nitrogen are examined by comparing the zero-and first-density coefficients with the trends shown at lower temperatures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00503996
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  • 36
    Digitale Medien
    Digitale Medien
    Compressibility and sound velocity measurements on N2 up to 1 GPa (1988)
    Springer
    International journal of thermophysics 9 (1988), S. 103-116 
    Details
    ISSN: 1572-9567
    Schlagwort(e): adiabatic compressibility ; equation of state ; density ; high pressure ; isothermal compressibility ; nitrogen ; pVT ; sound velocity ; ultrasonics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A gas expansion technique has been used to determine the pVT properties of N2 up to 1 GPa at 298.15 K, with an accuracy of 0.08% in density, 1 mK in temperature, and 0.05%+0.2 MPa in pressure. The sound velocity has been measured by a phase-comparison pulse-echo technique between 123 and 298 K at intervals of 25 K and at pressures up to 1 GPa, with an accuracy of better than 0.02% in sound velocity, 10 mK in temperature, and 0.05%+0.2 MPa in pressure. An equation of state is presented that correlates the density data over the wide pressure range of 36–1000 MPa with maximum deviations between the calculated and the experimental densities of less than 0.05%.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00504003
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  • 37
    Digitale Medien
    Digitale Medien
    New equations for enthalpy of vaporization from the triple point to the critical point (1988)
    Springer
    International journal of thermophysics 9 (1988), S. 567-575 
    Details
    ISSN: 1572-9567
    Schlagwort(e): alcohols ; alkanes ; carbon dioxide ; nitrogen ; propylene ; water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Two new equations are proposed for the enthalpy of vaporization from the triple point to the critical point. One of these equations containing four parameters is exceptionally good for fitting the data. The other equation containing three parameters is quite adequate for fitting the data but it is exceptionally suited for interpolation when the data do not cover the entire range. These equations have been tested using the enthalpy of vaporization of water from the triple point to the critical point and are compared with other equations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00503155
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  • 38
    Digitale Medien
    Digitale Medien
    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica II. Cacao and wood production, litter production and decomposition (1988)
    Springer
    Agroforestry systems 6 (1988), S. 37-48 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium ; litter production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract During 7 years (1979–1985) cacao harvests (beans and husks) have been recorded for the agroforestry systems ofTheobroma cacao underCordia alliodora andErythrina poeppigiana shade trees. The mean oven dry cacao yields were 626 and 712 kg.ha−1.a−1 cocoa beans underC. alliodora andE. poeppigiana respectively. Harvests have gradually increased over the years and the plantation has now reached maturity. Annual extraction of N, P, K, Ca and Mg in fruits, which is relatively small, was calculated on the basis of chemical analyses. The following average values were found (kg.ha−1.a−1): At the age of 8 years, theC. alliodora trees have reached 26.7 cm diameter (DBH) and 14.0 m in height. Mean annual growth (from age 5 to 7) is 14.6 m3.ha−1.a−1. Natural plant residue production has been measured for 4 years (Nov. 1981–Oct. 1985). UnderE. poeppigiana it has reached a value of 8.91 t.ha−1.a−1 and underC. alliodora 7.07 t.ha−1.a−1. The shade trees have contributed 57 and 47% respectively. Transference and decomposition rates are high and important in the nutrient cycles. The nutrient content of the litter was analysed and corresponding average yearly transfers were (kg.ha−1.a−1):
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02220107
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  • 39
    Digitale Medien
    Digitale Medien
    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica III. Cycles of organic matter and nutrients (1988)
    Springer
    Agroforestry systems 6 (1988), S. 49-62 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Models for cycles for organic matter and nutrients element (N, P, K, Ca and Mg) are presented for the agroforestry systems of cacao (Theobroma cacao) withCordia alliodora orErythrina poeppigiana in Turrialba, Costa Rica. For the models, system reserves (soil, humus, vegetation divided into leaves, branches, stems, fine roots, fruits) and transference between compartments (production and decomposition of litter residues) inputs (fertilizer, rainfall) and outputs (harvests) of the system are considered. The implications of the models are discussed in detail. Aspects of net primary production in the systems studied are considered. N fixation is calculated on the basis of balances. Analysis of soil water showed high variations that coincided with rainfall patterns and pruning of theE. poeppigiana.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02220108
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  • 40
    Digitale Medien
    Digitale Medien
    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica III. Cycles of organic matter and nutrients (1988)
    Springer
    Agroforestry systems 6 (1988), S. 49-62 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Models for cycles for organic matter and nutrients element (N, P, K, Ca and Mg) are presented for the agroforestry systems of cacao (Theobroma cacao) withCordia alliodora orErythrina poeppigiana in Turrialba, Costa Rica. For the models, system reserves (soil, humus, vegetation divided into leaves, branches, stems, fine roots, fruits) and transference between compartments (production and decomposition of litter residues) inputs (fertilizer, rainfall) and outputs (harvests) of the system are considered. The implications of the models are discussed in detail. Aspects of net primary production in the systems studied are considered. N fixation is calculated on the basis of balances. Analysis of soil water showed high variations that coincided with rainfall patterns and pruning of theE. poeppigiana.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02344745
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  • 41
    Digitale Medien
    Digitale Medien
    Effect of nitrogen, phosphorus and potassium on spikelet sterility induced by low temperature at the reproductive stage of rice (1988)
    Springer
    Plant and soil 109 (1988), S. 31-36 
    Details
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; phosphorus ; potassium ; rice ; low temperature ; reproductive stage ; flag leaf ; auricle distance ; spikelet sterility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Spikelet sterility induced by low temperature at the reproductive stage of rice increased further with the increase of nitrogen supply. Spikelet sterility in Fujisaka-5 did not increase due to low temperature when nitrogen supply was increased from 10 to 40 ppm and at 80 ppm nitrogen supply it was less affected than IR36. Total nitrogen content in the leaves increased with the increase of nitrogen supply and was forced to be associated with the spikelet sterility induced by low temperature. Based on auricle distance between the last two leaves, the most sensitive stage to low temperature damage differed in Fujisaka-5 and IR36. Spikelet sterility induced by low temperature for 10 days was very high in both the varieties and the effect of nitrogen was not clear. The effect of phosphorus on the spikelet sterility induced by low temperature at reproductive stage was not clear except that at the highest phosphorus (P) level (10 ppm) the spikelet sterility increased both in Fujisaka-5 and IR36. Spikelet sterility induced by low temperature at the reproductive stage of rice decreased with the increase of Potassium (K) supply in both Fujisaka-5 and IR36. With an increase of potassium supply, nitrogen (N) content decreased in the leaves and panicles and spikelet sterility induced by low temperature decreased with an increase of the K to N ratio in the leaves and panicles. The results suggest that potassium might play a major role to counteract the low temperature damage at the reproductive stage of rice.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02197577
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  • 42
    Digitale Medien
    Digitale Medien
    Comparisons of primary production and nutrients absorption by aMiscanthus sinensis community in different soils (1988)
    Springer
    Plant and soil 112 (1988), S. 143-149 
    Details
    ISSN: 1573-5036
    Schlagwort(e): absorption ; clay ; Miscanthus sinensis ; nitrogen ; phosphorus ; primary production ; serpentine gangue ; standing biomass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Soil properties, primary production, nitrogen and phosphorus uptake in aMiscanthus sinensis community on serpentine gangue area were compared with that on nonserpentine area. Soil water content, soil pH and nitrogen content were quite different between the serpentine gangue area and nonserpentine area; but phosphorus content of the soil was similar between the two sites. The maximum above-ground net production in the serpentine gangue and nonserpentine areas was 4.5±0.2 kg m−2 yr−1 and 7.8±0.2 kg m−2 yr−1, respectively. The total maximum standing biomass in the serpentine gangue and nonserpentine areas was 8.5±0.8 kg m−2 and 11.9±0.4 kg m−2, respectively. Nitrogen uptake by plants in the nonserpentine area was 2.4 times greater than that in the serpentine gangue area. Phosphorus uptake by plants were similar for the two sites. The most probable reasons for the small biomass produced by theMiscanthus sinensis community in this serpentine gangue area are the low levels of nitrogen and water availability in the soil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02181764
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  • 43
    Digitale Medien
    Digitale Medien
    Mineralization of N and P along a trophic gradient in a freshwater mire (1988)
    Springer
    Biogeochemistry 6 (1988), S. 31-43 
    Details
    ISSN: 1573-515X
    Schlagwort(e): nitrogen ; phosphorus ; mineralization ; productivity ; peatlands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract Release of inorganic nitrogen and phosphorus in the soil of a peatland (fen) in The Netherlands was measured by means of an in situ incubation technique. Three sampling stations were chosen along a gradient in the plant productivity and water chemistry of the fen. The station with the highest biomass production was located near the ditch that supplied the fen with water in amounts matching water losses through evaporation and downward percolation to the groundwater. Water chemistry at this station strongly resembled that of the ditch water. The two stations remote from the ditch had much lower plant biomass, and significantly lower pH, conductivity, and calcium and bicarbonate concentrations. The vegetation at these two stations was characterized by a thick Sphagnum carpet. The release of inorganic N and P was much faster at the two stations remote from the ditch than at that located near the ditch. The differences in mineralization rate are probably due to the differences in water chemistry; phosphates are more soluble at low than at high pH. The fast N mineralization at stations with a thick Sphagnum carpet may be related to the chemical composition of Sphagnum litter. The difference in productivity is not explained by the N and P mineralization rates. Direct supply of N and P from the ditch are probably the main cause of the high productivity at the station bordering the ditch.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00002931
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  • 44
    Digitale Medien
    Digitale Medien
    Effects of nitrogen fertilizer and weed control on nutritive quality of carrots (Daucus carota L.) (1988)
    Springer
    Plant foods for human nutrition 38 (1988), S. 67-73 
    Details
    ISSN: 1573-9104
    Schlagwort(e): carrots ; carotene ; T.S.S. ; herbicides ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The nutritive quality of carrots, obtained from different herbicide-treated plots and under different levels of nitrogen application ranging from zero to 80kg nitrogen/ha, was compared. There were significant differences in carotene content, T.S.S. (total soluble solids) and organolptic characteristics under the influence of different treatments. The maximum carotene content, T.S.S. and organoleptic characteristics were observed with the application of 80 kg. nitrogen/ha and fluchloralin herbicide at 0.90 and 1.20 kg/ha.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01092312
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  • 45
    Digitale Medien
    Digitale Medien
    Protein limitation of a tree leaf feeding Lepidopteran (1986)
    Springer
    Entomologia experimentalis et applicata 41 (1986), S. 115-120 
    Details
    ISSN: 1570-7458
    Schlagwort(e): dry matter budget ; nitrogen ; protein ; nutritional ecology ; growth efficiencies ; Datana ministra ; Tilia americana
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'hypothèse suivant laquelle la croissance des larves d'insectes est limitée par l'insuffisance des protéines disponibles dans les feuilles d'arbres a été examinée par l'alimentation des chenilles de Datana ministra Drury sur feuilles développées de Tilia americana L. enduites d'une mixture de protéines d'oeuf et de lait. Des chenilles de second stade, prélevées dans des colonies naturelles, ont été séparées en un lot témoin élevé en masse sur feuilles coupées et un lot expérimental élevé sur feuiles coupées mais enduites de protéines. Le bilan en matière sèche, le taux de croissance, la relation entre ce taux de croissance et la quantité de matière ingérée, le poids des prénymphes ont été déterminés sur 10 chenilles de dernier stade dans chaque lot. Les chenilles ayant consommé un supplément de protéine ont présenté un plus faible taux d'ingestion et un plus faible rendement de croissance, mais une meilleure efficacité apparente d'ingestion et un meilleur taux apparent d'assimilation que les témoins. Le complément protéique n'a pas eu d'effet sur le taux de croissance des chenilles de 5ème stade bien que l'alimentation avec addition de protéines ait provoqué la nymphose à un poids larvaire plus faible. L'addition de protéines avait provoqué une chargé métabolique pour les chenilles, peut-être en provoquant une demande d'excrétion d'azote excessive ou en créant un déséquilibre osmotique, ce qui aurait provoqué une réduction du taux de croissance et du poids des chenilles malgré un taux d'assimilation supérieur. Ces résultats ne confirment pas l'hypothèse que les insectes des arbres sont carencés en protéines.
    Notizen: Abstract The hypothesis that arbivorous insects are protein limited was tested by feeding larvae of Datana ministra mature leaves of Tilia americana that were coated with a mixture of protein. Larvae fed the protein supplement had a lower ingestion rate and net growth efficienty but higher apparent digestion efficiency and apparent assimilation rate than control larvae. Protein supplement had no effect on the rate of growth of 5th instar larvae although larvae fed added protein pupated at a lower weight than control larvae. The added protein placed a metabolic load on the larvae, perhaps by excessive nitrogen excretion demands and osmotic imbalance. The results do not support the hypothesis that arbivorous insects are protein limited.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00195566
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  • 46
    Digitale Medien
    Digitale Medien
    A comparative study on the intrinsic rates of increase ofCyrtobagous singularis andC. salviniae on the water weedSalvinia molesta (1986)
    Springer
    Entomologia experimentalis et applicata 42 (1986), S. 231-237 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Curculionidae ; Cyrtobagous singularis ; Cyrtobagous salviniae ; Salvinia molesta ; population increase ; survivorship ; fecundity ; fertility ; biological control ; temperature ; nutrition ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les taux intrinsèques d'accroissement (rm) deC. salviniae du Bresil et deC. singularis de Trinidad, ont été établis au laboratoire à 23°C; 27°C; 31°C, sur des plants deS. molesta riches en azote. Les différences entre les rm des deux espèces provenaient pour l'essentiel de la ponte et de la mortalité préimaginale. Aux 3 températures, les valeurs de rm deC. salviniae (0.210; 0.366; 0.404) étaient supérieures à celles deC. singularis (0.148; 0.140; 0.064). A toutes les températuresC. salviniae a pondu 7 fois plus d'oeufs queC. salviniae; à 31°C, la ponte a été réduite de 45% pour les 2 espèces et été accompagnée d'une diminution des taux d'éclosion. La ponte deC. salvinae était presque continue (92% des semaines avec des oeufs), tandis que celle deC. singularis était intermittent (50% des semaines avec pontes), les interruptions étant en moyenne de 2 semaines. La teneur deS. molesta en azote a affecté la reproduction deC. singularis plus que celle deC. salviniae; un accroissement de 0.1% en poids sec, augmentant les pontes hebdomadaires respectivement de 7% et de 3.6%. Les différences de valeur de rm des 2 espèces sont examinées pour évaluer leurs potentialités comme éléments de la lutte biologique.
    Notizen: Abstract The intrinsic rates of increase (rm) ofCyrtobagous salviniae Calder & Sands from Brazil andC. singularis Hustache from Trinidad W.I., were determined in the laboratory at 23°C, 27°C and 31°C on nitrogen-rich plants of the aquatic weed,Salvinia molesta Mitchell. Variation in oviposition and immature survivorship accounted for most of the differences between species in rm values (exponential growth of a stable-age population in a non-limiting environment). Values for rm were higher forC. salviniae (0.210, 0.366, 0.404) than forC. singularis (0.148, 0.140, 0.064) at the three temperatures respectively. At all temperatures,C. salviniae laid seven times more eggs thanC. singularis while at 31°C oviposition was reduced for both species by 45%, and was accompanied by a reduction in egg hatch. Oviposition byC. salviniae was almost continuous (92% of weeks with some eggs laid) whereas oviposition byC. singularis was intermittent (50% of weeks) with intervals averaging 3 weeks without oviposition. Nitrogen concentration inS. molesta affected reproduction byC. singularis more thanC. salviniae, an increase of 0.1% (dry wt) increasing weekly oviposition by 7.0% and 3.6% respectively. The differences in rm for the two weevil species are discussed in relationship to their potential as biological control agents.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00629309
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  • 47
    Digitale Medien
    Digitale Medien
    Fertilizer and liming value of lime-treated sewage sludge (1986)
    Springer
    Nutrient cycling in agroecosystems 8 (1986), S. 313-328 
    Details
    ISSN: 1573-0867
    Schlagwort(e): fertilizers ; lime ; lucerne ; nitrogen ; phosphorus ; sewage sludge
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment was conducted with lucerne on a strongly acidic and phosphorus deficient soil to determine the liming and phosphorus and nitrogen fertilizer value of an undigested, lime-treated sewage sludge. The results are presented in terms of calculated combinations of lime, nitrogen and phosphorus fertilizer required to obtain the same lucerne yield (or soil pH or extractable phosphorus level) as achieved with 5 or 10 t ha−1 of dried sludge. The sludge was a good source of lime, phosphorus and nitrogen. The sludge phosphorus was 49% as effective as the fertilizer phosphorus in raising extractable phosphorus in the soil to the level required for crop growth. The calcium carbonate of the sludge raised soil pH more effectively than agricultural lime, probably because of finer particle size in the former. It was not possible to achieve the yield obtained with 25 t ha−1 of sludge with combinations of agricultural lime, and nitrogen and phosphorus fertilizers at high rates of application. This was attributed to the effects of the sludge on improving soil physical properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01048634
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  • 48
    Digitale Medien
    Digitale Medien
    Recovery of15N-labelled fertilizer by sugar beet—spring wheat and winter rye—sugar beet cropping sequences (1986)
    Springer
    Nutrient cycling in agroecosystems 8 (1986), S. 269-278 
    Details
    ISSN: 1573-0867
    Schlagwort(e): nitrogen ; nitrogen-15 ; nitrogen efficiency ; nitrogen balance ; residual nitrogen ; sugar beet ; spring wheat ; winter rye
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The recovery of15N labelled ammonium fertilizer was studied during two cropping sequences: sugar beet—spring wheat and winter rye—sugar beet with the labelled N applied to the first crop of each sequence. The difference between fall and spring application was also investigated. For the first cropping sequence 100 kg N ha−1 labelled with 11.4%15N atom excess (a.e.) was applied to the sugar beets. This labelled N was followed in the sugar beets, in the soil profile at harvesting time as well as in the spring wheat of the following year. The first crop of sugar beet recovered 43–46% of the applied N, with 26–29% remaining in the soil at harvesting time and 25–31% could not be accounted for. Of the residual N, less than 1% could be recovered by the next crop of spring wheat. For the second cropping sequence 50 kg N ha−1 labelled with 11.5%15N a.e. was applied to the winter rye and followed in the winter rye and in the sugar beets of the following year. The recovery of the labelled fertilizer N applied to the winter rye of the second sequence was 20–27% and the sugar beets of the next year could only recover 2%. With respect to time of application, no difference in fertilizer N recovery was found between fall or spring application for the two sequences.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01048629
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  • 49
    Digitale Medien
    Digitale Medien
    Response of two okra (Abelmoschus esculentus L. Moench) varieties to fertilizers: Growth and nutrient concentration as influenced by nitrogen and phosphorus application (1986)
    Springer
    Nutrient cycling in agroecosystems 8 (1986), S. 297-306 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Growth ; nutrient concentration ; nitrogen ; okra (Abelmoschus esculentus L. Moench) phosphorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The growth response and nutrient concentration in okra (Abelmoschus esculentus L. Moench) as influenced by four nitrogen rates (0, 25, 50 and 100 kg ha−1) and three phosphorus rates (0, 13 and 26 kg ha−1) were examined using two varieties (‘White velvet’ and ‘NHAE 47-4’). Nitrogen application generally increased fruit and shoot dry weights markedly whereas phosphorus increased them only moderately. Leaf and primary branch production and plant height were also enhanced by nitrogen fertilization up to 100 kg N ha−1 but were not influenced by phosphorus application. The application of nitrogen enhanced the concentration of N, P and K in fruits and N and Mg in leaves while P and K concentrations in leaves were depressed. Nutrient concentrations in plant tissues were also partly a function of plant age and variety.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01048632
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  • 50
    Digitale Medien
    Digitale Medien
    Comparisons of the fertilizing and liming properties of lime-treated sewage sludge with its incinerated ash (1986)
    Springer
    Nutrient cycling in agroecosystems 9 (1986), S. 187-197 
    Details
    ISSN: 1573-0867
    Schlagwort(e): lime ; lucerne ; nitrogen ; phosphorus ; ryecorn ; ryegrass ; sewage sludge ; sewage ash
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two field experiments were conducted to compare the fertilizing and liming properties of dried lime-treated sewage sludge with its incineration product (ash). One experiment used a mixture of ryecorn and ryegrass on a relatively fertile soil and the other lucerne on a strongly acidic and phosphorus deficient soil. The first harvest of the ryecorn-ryegrass experiment showed small but significant linear responses in dry matter yield to both ash and sludge. Ash applications did not affect foliage nitrogen and phosphorus concentrations, or uptakes, but sludge applications increased these significantly. Sludge also increased the concentrations of K, S, Mg, Cu and Zn but ash only increased the concentrations of S and Mg. At the second harvest (ryegrass) 5 t ha−1 of sludge increased dry matter yield and foliage nitrogen and phosphorus concentrations whereas ash had no effect. Levels of phosphorus extracted from the soil were increased by both amendments but the sludge was much more effective than the ash. Both ash and sludge raised soil pH. In the lucerne experiment comparisons between sludge and ash were calculated from response surfaces fitted to the data which showed marked increased in soil pH and dry matter yield. Sludge markedly increased extractable phosphorus whereas ash had no effect. The sludge was 22% as effective as ash in raising soil pH to 6.5. The amounts of ash required to obtain the same yield as 10 t ha−1 of sludge were 5.78, 12.78 and 6.39 t ha−1 respectively for three successive harvests. These results and those for foliage concentrations of nitrogen and phosphorus were also ascribed to the much greater availability of the sludge phosphorus than the ash phosphorus, and the presence of nitrogen in the sludge but not in the ash.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01050345
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  • 51
    Digitale Medien
    Digitale Medien
    Fertilization of tropical rice: A case study on Bangkok plain (1986)
    Springer
    Nutrient cycling in agroecosystems 10 (1986), S. 97-112 
    Details
    ISSN: 1573-0867
    Schlagwort(e): fertilizer ; nitrogen ; phosphorus ; plant analysis ; nutritional status
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This study consisted of a survey on the nutritional status of rice plants in relation to nutrient application and yield in 70 farmers' fields in four provinces of Bangkok plain during the 1977 wet season. In addition a series of fertilizer experiments were carried out on rice experimental stations in the same provinces to study yield response to N and P fertilization and to develop a fertilizer recommendation system based on plant analysis. The average grain yield in the survey was 3.2 t ha−1 and the early (high yielding varieties), medium (local) and late maturity (local) types yielded 3.3, 2.8 and 3.0 t ha−1, respectively. The average amount of fertilizers applied to these maturity types were 33, 15 and 7 kg N ha−1 and 15, 8 and 6 kg P ha−1, respectively. Regression analysis indicated only a slight correlation between yield and any level of fertilizer application. On experimental stations yields over 6 t ha−1 were obtained with applications of N over 100 kg ha−1 and P over 22 kg ha−1. Evaluation of nutritional status of plants based on plant analysis showed that in all provinces there were strong and widespread nutrient deficiences primarily of N and secondarily of P, and possibly of some other nutrients. Fertilizer application based on plant analysis gave high yield responses. It was concluded that the major constraints of yield on Bangkok plain are too low fertilizer application especially of N, and unbalanced fertilization of N and P.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01074365
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  • 52
    Digitale Medien
    Digitale Medien
    The role of nitrogen and phosphorus in the development of Cladophora glomerata (L.) Kutzing in the Manawatu River, New Zealand (1986)
    Springer
    Hydrobiologia 131 (1986), S. 23-30 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Cladophora ; periphyton ; filamentous algae ; nitrogen ; phosphorus ; physiological indicator tests ; bioassays ; Manawatu River ; New Zealand
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Physiological indicators of nitrogen and phosphorus deficiency were used to determine the role of these nutrients in the development and proliferation of Cladophora in the Manawatu River, New Zealand. Nitrogen indicator tests showed that surplus nitrogen was available at all times. During a sustained low flow period when the dissolved reactive phosphorus was between 4–5 mg m−3, phosphorus indicator tests revealed that the Cladophora proliferations were phosphorus deficient. A downstream trend of reduced nitrogen and phosphorus availability was also observed during this period. Sudden high river flows were frequent and had a major influence on the Cladophora biomass.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008320
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  • 53
    Digitale Medien
    Digitale Medien
    Decomposition and nutrient dynamics of litter from four species of freshwater emergent macrophytes (1986)
    Springer
    Hydrobiologia 131 (1986), S. 215-223 
    Details
    ISSN: 1573-5117
    Schlagwort(e): decomposition ; model ; nitrogen ; phosphorus ; marsh ; Typha latifolia ; Carex lacustris ; Calamagrostis canadensis ; Zizania aquatica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nitrogen and phosphorus concentrations and mass remaining were followed for 30 months in decomposing litter of the perennial macrophytes Typha latifolia L., Carex lacustris Willd., Calamagrostis canadensis (Michx.) Nutt., and the annual Zizania aquatica L. in a fresh water tidal marsh in Massachusetts. Step-wise decreases in the mass remaining that corresponded to seasonal temperature changes were observed for all species. A model that assumes that initial litter inputs to the marsh surface consist of refractory and labile fractions and that the decay rate of the labile fraction is an exponential function of inverse temperature produced an acceptable description of the observed litter decomposition. The model suggests that a refractory fraction of 11% of initial litter weight of the annual Zizania and from 18 to 23% in the perennial species persists while labile organics are largely degraded within 1 yr. Zizania litter, which had the highest initial concentrations of both N and P, contained the lowest amounts of N and P after 30 months of decomposition. In the three perennial species studied, which are the dominant macrophytes in this marsh, there was a net accumulation of N and P in litter during the first 5 months of decomposition that was about 36% and 100%, respectively, of the annual N and P losses by vegetation in litterfall. This phase of nutrient accumulation was followed by nutrient release, particularly of N, after plant roots had invaded the litter. This sequence of nutrient accumulation, root invasion, and nutrient release represents a mechanism for nutrient conservation and/or accumulation in this ecosystem.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008857
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  • 54
    Digitale Medien
    Digitale Medien
    Sources of organic nitrogen, phosphorus and carbon in antarctic streams (1986)
    Springer
    Hydrobiologia 134 (1986), S. 215-225 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Antarctica ; carbon ; glaciers ; nitrogen ; phosphorus ; streams
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Dissolved and particulate organic materials were analysed in 14 streamwaters of the McMurdo Sound region of Antarctica. These streams are fed by glacial meltwaters and pass through catchments largely devoid of terrestrial vegetation. Nonetheless they contained measurable amounts of organic material in both dissolved and particulate form. Most of the dissolved organic carbon (DOC) values lay in the range 1–3 g C m−3. Higher values were recorded close to penguin rookeries on the coast. Dissolved organic nitrogen (DON) concentrations were generally two orders of magnitude less than DOC and in flowing waters with rich blue-green algal growth DON increased with distance downstream. Dissolved organic phosphorus levels were generally much lower than DON, but highly variable. Particulate organic carbon concentrations (both fine and coarse) were unexpectedly high. Five sources of organic matter were identified: birdlife (only near the coast), autochthonous algal production (especially important for DON), streambed soils (important at first flows), lacustrine and marine sediments, through which certain streams and glaciers cut, and the glacial ice, which received organic input from wind-blown particulates, snowfall and the underlying bedrock of sedimentary origin. Highest organic levels were recorded in the first melt down the glacier face, suggesting that winter deposition of organic materials may be especially important.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008490
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  • 55
    Digitale Medien
    Digitale Medien
    The Utricularia-Cyanophyta association and its nitrogen-fixing capacity (1986)
    Springer
    Hydrobiologia 141 (1986), S. 255-261 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Utricularia inflexa ; Cyanophyta ; association ; nitrogen ; fixation ; Tanzania
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Utricularia inflexa Forsk. growing in a shallow lake near Dar es Salaam, Tanzania was found to be abundantly associated with blue-green algae and other microorganisms, though blue-green algae were not found in the lake water. The epiphytes occurred both on the outer surfaces of the macrophyte and inside its traps. Seven genera of the Cyanophyta were observed, amongst which Anabaena was the most abundantly and consistently associated. Both epiphytes on the outer surfaces of the macrophyte and those inside mature traps fixed nitrogen in situ. Mature parts of the macrophyte fixed nitrogen at higher rates than immature parts, indicating the former was associated with a greater abundance of nitrogen fixers. The Utricularia-Cyanophyta association showed a nitrogen fixation (acetylene reduction) rate of 2012 nmol C2H4 g−1 dry weight h−1 or, in terms of lake area, of 4 500 nmol C2H4 m−2 h−1. The relative contributions of blue-green algae and bacteria were not determined. It is proposed that the association may involve a degree of physiological interdependence and that the association has potential as a biofertilizer for rice.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00014219
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  • 56
    Digitale Medien
    Digitale Medien
    Influence of climate, soil moisture, and succession on forest carbon and nitrogen cycles (1986)
    Springer
    Biogeochemistry 2 (1986), S. 3-27 
    Details
    ISSN: 1573-515X
    Schlagwort(e): Carbon ; climate ; forests ; landscape ecology ; nitrogen ; productivity ; soil moisture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The interactions between the biotic processes of reproduction, growth, and death and the abiotic processes which regulate temperature and water availability, and the interplay between the biotic and abiotic processes regulating N and light availabilities are important in the dynamics of forest ecosystems. We have developed a computer simulation that assembles a model ecosystem which links these biotic and abiotic interactions through equations that predict decomposition processes, actual evapo-transpiration, soil water balance, nutrient uptake, growth of trees, and light penetration through the canopy. The equations and parameters are derived directly from field studies and observations of forests in eastern North America, resulting in a model that can make accurate quantitative predictions of biomass accumulation, N availability, soil humus development and net primary production.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02186962
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  • 57
    Digitale Medien
    Digitale Medien
    Nitrate increases in soil water following conversion of chaparral to grass (1986)
    Springer
    Biogeochemistry 2 (1986), S. 53-65 
    Details
    ISSN: 1573-515X
    Schlagwort(e): Chaparral conversion ; nitrogen ; nitrate ; soil water ; stream water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract An Arizona watershed converted from chaparral to grass, released high concentrations of nitrate to stream water. The nitrate originated from the rooting zone of the decomposing shrubs. High nitrate concentrations (44–373 ppm) were found in soil solutions from 1.5-, 3.0-, and 4.6-m depths on the converted watershed as compared with low nitrate concentrations (0.2–6.2 ppm) found in an adjacent undisturbed area. Soil solution nitrate concentrations at the 0.3-m depth were generally low, especially in the untreated area. High nitrate concentrations were balanced mainly by relative decreases in bicarbonate anions in the soil solutions and in the stream water. Multiple stepwise regression analyses showed improvement in the regression of bicarbonate on nitrate when chloride and sulfate anions were entered as variables.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02186965
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  • 58
    Digitale Medien
    Digitale Medien
    Concepts of sulfur, carbon, and nitrogen transformations in soil: evaluation by simulation modeling (1986)
    Springer
    Biogeochemistry 2 (1986), S. 163-177 
    Details
    ISSN: 1573-515X
    Schlagwort(e): sulfur ; carbon ; nitrogen ; mineralization ; simulation model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The dynamics of sulfur immobilization and mineralization in soil were simulated to test hypotheses about their regulation by the availability of carbon and nitrogen. The concept of chemical bond classes was incorporated into the model to account for variation in composition of carbon, nitrogen, and sulfur compounds. Microbial biomass was differentiated into bacteria and fungi, and the element ratios of both groups were assumed to vary. Organic residues were divided between dead microbes plus microbial products, and the more labile fraction of stabilized soil organic matter. Concepts and hypotheses in the model were tested by applying it to data on microbial biomass, sulfate, nitrate, and CO2 evolution obtained in laboratory incubations of two soils amended with sulfate and cellulose. An important mechanism of regulation tested in the model was the stimulation of sulfohydrolase enzyme production depending on sulfur stress in microbial biomass. The hypothesis that excess sulfate is stored as ester sulfate was supported by model dynamics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02180193
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  • 59
    Digitale Medien
    Digitale Medien
    NPK-fertilizer efficiency — a situation analysis for the tropics (1986)
    Springer
    Nutrient cycling in agroecosystems 10 (1986), S. 147-164 
    Details
    ISSN: 1573-0867
    Schlagwort(e): fertilizer efficiency ; nitrogen ; phosphorus ; potassium ; tropics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper examines the efficiency of applied N, P, and K fertilizers under tropical conditions. To meet their food demands, tropical countries are importing large quantities of fertilizers at an enormous cost. There is a need for improving crop yields at a reduced cost and a better understanding of the factors that contribute to the overall efficiency of applied fertilizers. It is estimated that under tropical condition, the efficiency of applied N is less than 50%, less than 10% for P and for K it is somewhere around 40%. Losses of N are mainly due to leaching, runoff and volatile losses of ammonia. Under flooding and in alternate wetting and drying conditions of rice lands and low lands, dentrification and volatile ammonia losses are considerable. The N losses from these soil could be minimized by proper management such as rate, methods and time of application. The coating of urea with S has shown some improvement in increasing efficiency. Nitrification and urea hydrolysis inhibitors can improve fertilizer efficiency in certain situations provided they are properly used. The efficiencies of these inhibitors depend on the nature of the chemical compounds, soil properties, and method of application. Low efficiency of applied P fertilizer is mainly due to retention of P by soil clay fractions and iron and aluminum hydroxides. Even though retained P is not available to the first crop, it is made available to a certain extent to the succeeding crops. The rate and methods of P applications and forms of P determine the efficiency of applied P fertilizers. The use of native rock phosphate along with P fertilizers on acid soils appears to be an attractive alternative in reducing the fertilizer cost. The loss of K in tropical soils is largely attributed to leaching and runoff. To reduce K loss by leaching, it is more advisible to apply K in split doses than a single dose. Liming has a beneficial effect in retention of K and reducing P fixation in acid soils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01074369
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  • 60
    Digitale Medien
    Digitale Medien
    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica (1986)
    Springer
    Agroforestry systems 4 (1986), S. 175-189 
    Details
    ISSN: 1572-9680
    Schlagwort(e): cacao ; shade trees ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; erythrina ; cordia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The agroforestry systems of cacao (Theobroma cacao) under laurel (Cordia alliodora) and cacao under poro (Erythrina poeppigiana) were studied at CATIE, Turrialba, Costa Rica. An inventory was taken of the organic matter and nutrients (N, P, K, Ca, and Mg) separating the species into their compartments (leaves, branches, trunks and roots). Studies of the litter and of the mineral soil (0–45 cm) yielded these results: Patterns of nutrient accumulation are discussed in relation to the characteristics of these agroforestry systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02028353
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  • 61
    Digitale Medien
    Digitale Medien
    A thermodynamic property formulation for nitrogen from the freezing line to 2000 K at pressures to 1000 MPa (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 503-511 
    Details
    ISSN: 1572-9567
    Schlagwort(e): equation of state ; nitrogen ; saturation properties ; thermodynamic properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A new fundamental equation explicit in Helmholtz energy for thermodynamic properties of nitrogen from the freezing line to 2000 K at pressures to 1000 MPa is presented. A new vapor pressure equation and equations for the saturated liquid and vapor densities as functions of temperature are also included. The techniques used for development of the fundamental equation are those reported in a companion paper for ethylene. The fundamental equation and the derivative functions for calculating internal energy, enthalpy, entropy, isochoric heat capacity (C v), isobaric heat capacity (C p), and velocity of sound are also included in that paper. The property formulation using the fundamental equation reported here may generally be used to calculate pressures and densities with an uncertainty of ±0.1%, heat capacities within ± 2%, and velocity of sound values within ±2%. The fundamental equation is not intended for use near the critical point.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00502385
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  • 62
    Digitale Medien
    Digitale Medien
    Determination of the thermal conductivity of argon and nitrogen over a wide temperature range through data evaluation and shock-tube experiments (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 647-662 
    Details
    ISSN: 1572-9567
    Schlagwort(e): argon ; data evaluation ; high temperature ; nitrogen ; shock-tube measurement ; thermal conductivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Reliable and well-established methods to measure the thermal conductivity of gases are available only in the moderate temperature range, namely, up to about 1000 K. In the present study, a set of the most probable thermal conductivity values of components of gaseous combustion products in a wide range of temperatures has been obtained through an optimum combination of three procedures: critical assessment of available data in the moderate temperature range, experimental determination by the shock-tube method at high temperatures, and theoretacal estimation of temperature dependence in the intermediate temperature range. Among the components of combustion products, one monatomic gas and one diatomic gas, namely, argon and nitrogen, were studied in the present paper. The shock-tube measurements have been performed in the temperature ranges 1000–4500 K for argon and 500–2200 K for nitrogen. The results of the critical evaluation and the shock-tube measurements have been combined with the aid of theoretically assumed temperature dependence of the thermal conductivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00502397
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  • 63
    Digitale Medien
    Digitale Medien
    Extended corresponding states as a tool for the prediction of the thermodynamic properties of mixtures (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 901-910 
    Details
    ISSN: 1572-9567
    Schlagwort(e): equation of state ; ethane ; extended corresponding states ; methane ; mixtures ; nitrogen ; P-V-T-x
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The principle of corresponding states, with one of its many extensions, is used to predict the thermodynamic properties of the binary mixtures N2-CH4 and CH4-C2H6. Comparisons of the predicted properties with experimental data are given to illustrate some of the powers and problems associated with the method. Problems encountered in modeling mixtures, which are not necessarily associated with the mathematical model of the equation of state, are also discussed. Wide-range equations of state for the two binary systems mentioned above are presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00503846
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  • 64
    Digitale Medien
    Digitale Medien
    Temperature-related effects of three insects on growth ofSalvinia molesta in Brazil (1986)
    Springer
    BioControl 31 (1986), S. 19-26 
    Details
    ISSN: 1573-8248
    Schlagwort(e): Salvinia ; Cyrtobagous ; Samea ; Paulinia ; Biocontrol ; temperature ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé L'effet deCyrtobagous salviniae, deSamea multiplicalis et dePaulinia acuminata sur la croissance deSalvinia molesta a été étudié en relation avec la température dans des cages implantées dans 2 situations au Brésil, un canal avec de l'eau courante et une lagune avec de l'eau stagnante. Chaque espèce réduit la croissance deS. molesta dans une gamme de températures des feuilles s'étendant de 16° à 30°C, les dégâts augmentent avec l'accroissement de la température. Il n'y a pas de différence entre les 3 espèces vis-à-vis de leur réaction à la température. Ces résultats et leur implication quant au rendement de ces insectes comme agents biologiques de lutte contreS. molesta sont discutés.
    Notizen: Abstract The effect ofCyrtobagous salviniae, Samea multiplicalis, andPaulinia acuminata on the growth ofSalvinia molesta was assessed in relation to temperature in field cages at 2 sites in Brazil, a canal with running-water and a lagoon with stillwater. Each insect species reduced the growth ofS. molesta over a mean leaftemperature range of 16–30°C, causing more damage as temperature increased. There was no difference between the 3 species in response to temperature. These results and their implication to the performance of these insects as biological control agents againstS. molesta are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02390916
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  • 65
    Digitale Medien
    Digitale Medien
    Mineral element content in Ulva lactuca L. with reference to eutrophication in Hong Kong coastal waters (1981)
    Springer
    Hydrobiologia 77 (1981), S. 43-47 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Eutrophication ; pollution indicator ; mineral element ; nitrogen ; phosphorus ; Ulva lactuca ; Hong Kong
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The amounts of tissue nitrogen, phosphorus, potassium, sodium, calcium and iron were estimated in the green alga Ulva lactuca L. collected from 9 rural and 14 urban littoral sites in the waters around Hong Kong Island during 1978 and 1979. The mean levels of tissue nitrogen and phosphorus were respectively 65% and 87% more in urban sites than in rural ones. Very significant correlation (r = 0.920) was found between the logarithmic concentration of seawater inorganic nitrogen and that of tissue nitrogen. The same applied to soluble reactive phosphorus in seawater and tissue phosphorus (r = 0.886). The levels of potassium, sodium and calcium in the alga were relatively uniform. However considerable variation in the level of iron was detected. The potential use of Ulva as an indicator species for eutrophication is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00006386
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  • 66
    Digitale Medien
    Digitale Medien
    The impact of urbanization on seasonal hydrologic and nutrient budgets of a small North American watershed (1981)
    Springer
    Hydrobiologia 77 (1981), S. 87-96 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Urbanization ; hydrologic budget ; nutrient budget ; seasonal budget ; nitrogen ; phosphorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Present day hydrologic and nutrient budgets have been measured and presettlement budgets estimated for a small urban watershed in Madison, Wisconsin. The importance of different seasons and sources to the total loading were compared for past and present conditions. The seasonal budget revealed that while spring contributes the greatest loadings in both scenarios, summer exhibits the greatest change in loadings from past to present. As for sources this seepage lake receives most of its water and N from groundwater; however, most P comes from surface runoff. The greatest impact on the watershed since settlement appears to be the large increase in runoff matched by a decrease in evapotranspiration and subsurface flow. This shift in hydrology is largely responsible for the substantial increase in P loading and the decrease in the N : P ratio of total loading. The significance of the lake's modified morphometry to areal and volumetric loading is also explored.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00006393
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  • 67
    Digitale Medien
    Digitale Medien
    The effects of varying culture nitrogen and phosphorus levels on nutrient uptake and storage by the waterhyacinth Eichhornia crassipes (Mart) Solms (1981)
    Springer
    Hydrobiologia 85 (1981), S. 17-22 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Eichhornia crassipes ; nitrogen ; phosphorus ; nutrient uptake ; nutrient storage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The uptake of nitrogen (N) by waterhyacinth (Eichhornia crassipes) was maximal when the culture solution contained a combination of 36 ppm N and 6,53 ppm phosphorus (P). N uptake was inhibited by increasing P or decreasing N in the culture medium. Uptake of P was stimulated by the elevation of either N or P or both. An increase of P above O ppm inhibited the accumulation of N. Similarly, the accumulation of P was enhanced by increasing levels of P but was reduced with increasing levels of N. Both N and P levels were always greatest in leaves; next highest in floats and lowest in roots. High tissue levels of these two nutrients and the capacity for nutrient removal from water by waterhyacinth indicates a possible role for this plant in the reduction of eutrophication in nutrient polluted waters as well as the use of harvested, dried tissue for fertilizer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011341
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Nitrogen and phosphorus dynamics in hot desert streams of Southwestern U.S.A. (1981)
    Springer
    Hydrobiologia 83 (1981), S. 303-312 
    Details
    ISSN: 1573-5117
    Schlagwort(e): nitrogen ; phosphorus ; streams ; deserts ; nutrient limitation ; production ; Arizona
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nitrogen to phosphorus ratios and concentrations of nitrate and soluble reactive phosphate are presented for an array of Southwestern streams as evidence that nitrogen is the limiting nutrient where such limitation occurs. Nitrate uptake in sections of intermittent streams was attributable to autotrophic activity. Uptake of soluble reactive phosphate was unrelated to any indicator of autotrophic activity, thus concentrations of this nutrient in desert and semi-desert stream waters may be controlled by other factors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008281
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    Mineral composition of Phragmites australis in Scottish lochs as related to eutrophication. I. Seasonal changes in organs (1981)
    Springer
    Hydrobiologia 85 (1981), S. 227-237 
    Details
    ISSN: 1573-5117
    Schlagwort(e): chemical composition ; eutrophication ; nitrogen ; phosphorus ; Phragmites australis ; Scottish lochs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Monthly levels of nitrogen, phosphorus, potassium, sodium, calcium, magnesium and iron in the organs (root, rhizome, stem, leaf and panicle) of Phragmites australis were determined from March to November, 1975 in Forfar Loch (polytrophic), Balgavies Loch (eutrophic) and Loch of the Lowes (mesotrophic), Scotland. Generally no consistent seasonal changes in the mineral levels were detected for the root, rhizome and panicle. For the stem and leaf, the levels of nitrogen, phosphorus, potassium, calcium and magnesium rose to a peak before declining for the rest of the season. Consistently higher levels of tissue nitrogen, phosphorus, potassium and calcium were found in the Forfar plants over those of Balgavies and Lowes, reflecting the very eutrophic condition in Forfar Loch. The mineral compositions in the reeds in the present study were compared with similar studies in other areas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00017612
    Standort Signatur Erwartet Verfügbarkeit
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