期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 618, 期 -, 页码 1173-1183出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.scitotenv.2017.09.183
关键词
Optimal N application rate; Crop yield; Economic income; Environmental cost; N uptake; N utilization
资金
- National Key Research & Development Plan [2016YFD0800101]
- National Natural Science Foundation of China [31572208]
- Newton Fund [BB/N013484/1]
- Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture, China [201003014]
- China Scholarship Council (Personnel Training Project of Agricultural Ecosystem Carbon and Nitrogen Gas Exchange and Mechanism of Non-point Source Pollution Control in Typical Watershed) [2015-7169]
Optimizing the nitrogen (N) application rate can increase crop yield while reducing the environmental risks. However, the optimal N rates vary substantially when different targets such as maximum yield or maximum economic benefit are considered. Taking the wheat-maize rotation cropping system on the North China Plain as a case study, we quantified the variation of N application rates when targeting constraints on yield, economic performance, N uptake and N utilization, by conducting field experiments between 2011 and 2013. Results showed that the optimal N application rate was highest when targeting N uptake (240 kg ha(-1) for maize, and 326 kg ha(-1) for wheat), followed by crop yield (208 kg ha(-1) for maize, and 277 kg ha(-1) for wheat) and economic income(191 kg ha(-1) for maize, and 253 kg ha(-1) for wheat). If environmental costs were considered, the optimal N application rates were further reduced by 20-30% compared to those when targeting maximum economic income. However, the optimal N rate, with environmental cost included, may result in soil nutrient mining under maize, and an extra input of 43 kg N ha(-1) was needed to make the soil N balanced and maintain soil fertility in the long term. To obtain a win-win situation for both yield and environment, the optimal N rate should be controlled at 179 kg ha(-1) for maize, which could achieve above 99.5% of maximum yield and have a favorable N balance, and at 202 kg ha(-1) for wheat to achieve 97.4% of maximum yield, which was about 20 kg N ha(-1) higher than that when N surplus was nil. Although these optimal N rates vary on spatial and temporal scales, they are still effective for the North China Plain where 32% of China's total maize and 45% of China's total wheat are produced. More experiments are still needed to determine the optimal N application rates in other regions. Use of these different optimal N rates would contribute to improving the sustainability of agricultural development in China. (c) 2017 Elsevier B.V. All rights reserved.
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