Results 261 to 270 of about 220,937 (307)

Nitrogen Fertilizers: Meeting Contemporary Challenges

AMBIO: A Journal of the Human Environment, 2002
At 81.7 million tonnes (Mt), commercial fertilizer nitrogen (N) accounts for approximately half of all N reaching global croplands today and supplies basic food needs for at least 40% of the population. The challenge is to continue to help meet that need while minimizing the risk of negative environmental impacts through improved N-use efficiency ...
Paul E, Fixen, Ford B, West
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Uptake of fertilizer nitrogen and soil nitrogen by rice using15N-labelled nitrogen fertilizer

Plant and Soil, 1980
Data from five field experiments using labelled nitrogen fertilizer were used to determine the relative effects of soil nitrogen and fertilizer nitrogen on rice yield. Yield of grain was closely correlated with total aboveground nitrogen uptake (soil+fertilizer), less closely correlated with soil nitrogen uptake and not significantly correlated with ...
K. R. Reddy, W. H. Patrick
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Nitrogen Fertilization II: Fertilizer Requirements

2016
The N balance allows the calculation of the fertilizer requirement which depends on the amount of N absorbed by the crop, the amount of inorganic N in the soil or produced by mineralization and N losses of the system, which are quantified by the Recovery Efficiency. A fertilization plan should take into account the variability of environmental factors,
Miguel Quemada, Antonio Delgado, Luciano Mateos, Francisco J. Villalobos   +3 more
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Nitrogen‐15 Variations in Fertilizer Nitrogen

Journal of Environmental Quality, 1974
AbstractNitrogen‐15 concentrations of some commonly used nitrogen fertilizers are measured. Ammonium‐nitrogen has lower and nitrate‐nitrogen has higher 15N concentrations than atmospheric nitrogen. The mean difference between both is about 4 δ 15N.
H. D. Freyer, A. I. M. Aly
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Environmental friendly nitrogen fertilization

Science in China Series C Life Sciences, 2005
With the huge intensification of agriculture and the increasing awareness to human health and natural resources sustainability, there was a shift towards the development of environmental friendly N application approaches that support sustainable use of land and sustain food production.
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Evaluating Decision Rules for Nitrogen Fertilization

Biometrics, 2000
Summary. It is important, both for farmer profit and for the environment, to correctly dose nitrogen fertilizer for crop growth. Fertilizer recommendations are embodied in decision rules, which give a recommended dose of nitrogen (N) as a function of information available at the time the decision is made.
Antoniadou, T., Wallach, Daniel
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Fertilizer Nitrogen Management

1989
ABSTRACT Nitrogen fertilizer supply is the primary nutrient limitation for both total world food supply and protein content. Unfortunately N fertilizer can also be a major contributor of N to ground water supplies if managed improperly. “Proper use” of N fertilizer involves accurate assessment of need before application.
G.A. PETERSON, W.W. FRYE
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Global assessment of nitrogen fertilizer: The SCOPE/IGBP nitrogen fertilizer rapid assessment project

Science in China Series C Life Sciences, 2005
Nitrogen (N) availability is a key role in food and fiber production. Providing plant-available N through synthetic fertilizer in the 20th and early 21st century has been a major contributor to the increased production required to feed and clothe the growing human population. To continue to meet the global demands and to minimize environmental problems,
Arvin R, Mosier, J Keith, Syers, John R, Freney   +2 more
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Liquid nitrogenous fertilizers

The Journal of Agricultural Science, 1959
The results show that liquid fertilizers generally gave lower yields of dry matter than conventional solid fertilizers in four experiments on grassland. In seven trials, on autumn wheat, spring wheat, sugar beet and kale, the efficiencies of the two forms of fertilizer were similar.Liquid fertilizers containing ammonia must be injected into the soil ...
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Nitrogen fertilizers promote denitrification

Biology and Fertility of Soils, 1997
A laboratory study was conducted to compare the effects of different N fertilizers on emission of N2 and N2O during denitrification of NO3 – in waterlogged soil. Field-moist samples of Drummer silty clay loam soil (fine-silty, mixed, mesic Typic Haplaquoll) were incubated under aerobic conditions for 0, 2, 4, 7, 14, 21, or 42 days with or without ...
R. L. Mulvaney, S. A. Khan, C. S. Mulvaney   +2 more
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