Global nitrogen budgets in cereals: a 50-year assessment for maize, rice and wheat production systems
| Autor: | Jagdish K. Ladha, C. van Kessel, Agnes Tirol-Padre, Debashis Chakraborty, C. K. Reddy, Himanshu Pathak, Daniel Richter, Kenneth G. Cassman, Sudhir Verma, David S. Powlson |
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| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
Crop residue Edible Grain Nitrogen chemistry.chemical_element engineering.material Oryza 01 natural sciences History 21st Century Zea mays Article Crop Humans Fertilizers Triticum Multidisciplinary biology 04 agricultural and veterinary sciences History 20th Century biology.organism_classification Manure Crop Production Agronomy chemistry 040103 agronomy & agriculture engineering Land degradation 0401 agriculture forestry and fisheries Environmental science Fertilizer 010606 plant biology & botany |
| Zdroj: | Scientific Reports |
| Popis: | Industrially produced N-fertilizer is essential to the production of cereals that supports current and projected human populations. We constructed a top-down global N budget for maize, rice and wheat for a 50-year period (1961 to 2010). Cereals harvested a total of 1551 Tg of N, of which 48% was supplied through fertilizer-N and 4% came from net soil depletion. An estimated 48% (737 Tg) of crop N, equal to 29, 38 and 25 kg ha−1 yr−1 for maize, rice and wheat, respectively, is contributed by sources other than fertilizer- or soil-N. Non-symbiotic N2 fixation appears to be the major source of this N, which is 370 Tg or 24% of total N in the crop, corresponding to 13, 22 and 13 kg ha−1 yr−1 for maize, rice and wheat, respectively. Manure (217 Tg or 14%) and atmospheric deposition (96 Tg or 6%) are the other sources of N. Crop residues and seed contribute marginally. Our scaling-down approach to estimate the contribution of non-symbiotic N2 fixation is robust because it focuses on global quantities of N in sources and sinks that are easier to estimate, in contrast to estimating N losses per se, because losses are highly soil-, climate- and crop-specific. |
| Databáze: | OpenAIRE |
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