Details

Autor(en) / Beteiligte

• Ladha, J K
• Tirol-Padre, A
• Reddy, C K
• Cassman, K G
• Verma, Sudhir
• Powlson, D S
• van Kessel, C
• de B Richter, Daniel
• Chakraborty, Debashis
• Pathak, Himanshu

Titel

Global nitrogen budgets in cereals: A 50-year assessment for maize, rice, and wheat production systems

Ist Teil von

• Scientific reports, 2016-01, Vol.6 (1), p.19355-19355, Article 19355

Ort / Verlag

England: Nature Publishing Group

Erscheinungsjahr

2016

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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.