期刊
FIELD CROPS RESEARCH
卷 124, 期 3, 页码 450-458出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.fcr.2011.08.002
关键词
Intensive agriculture; Synthetic N fertilizer; Theoretical N rate; High target yield; Soil N balance; Environmental risk
类别
资金
- Chinese National Basic Research Program [2009CB118606]
- Special Fund for Agricultural Profession [201103039]
- Foundation of the Chinese Ministry of Education [20100008110004]
- Innovation Group of the National Natural Science Foundation of China [30821003]
Nitrogen (N) is a crucial nutrient that requires careful management in intensive cropping systems because of its diverse beneficial and detrimental effects. Here we propose the concept of theoretical N rate (TNR) to answer the important question of how much fertilizer N should be applied to intensive systems based on the N fluxes due to transformation processes in the soil crop environment continuum. We define TNR as the theoretically calculated fertilizer N rate with the quantitative relationships of the core N fluxes among fertilizer N, soil N and crop uptake N in the crop root zone to obtain high target yield, maintain soil N balance and minimize environmental risk. We deduced one basic mathematical expression (N-fert = N-uptake - N-straw - N-fert3) and two simplified expressions [N-fert = (N-uptake - N-straw)/(1 - Coeff); N-fert congruent to N-uptake] for calculating the TNR. These expressions do not need much field experimentation or elaborate soil and plant testing to obtain information on crop N demand and soil N supply, and are simple to implement in farming practice to provide a very cost-effective approach. We consider this scheme to be a useful contribution to rational fertilizer practice, especially in developing countries where other N recommendation systems are usually not available and agricultural extension services are poorly developed or absent. (C) 2011 Elsevier B.V. All rights reserved.
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