Title: Fertilizer nitrogen recovery efficiencies in crop production systems of China with and without consideration of the residual effect of nitrogen
Authors: YAN XiaoyuanTI ChaopuVITOUSEK PeterCHEN DeliLEIP AdrianCAI ZucongZHU Zhaoliang
Citation: ENVIRONMENTAL RESEARCH LETTERS vol. 9 no. 9 p. 095002
Publication Year: 2014
JRC N°: JRC91292
ISSN: 1748-9326
URI: http://iopscience.iop.org/1748-9326/9/9/095002/
DOI: 10.1088/1748-9326/9/9/095002
Type: Articles in periodicals and books
Abstract: China is the world’s largest consumer of synthetic nitrogen (N), where very low rates of fertilizer N recovery in crops have been reported, raising discussion around whether fertilizer N use can be significantly reduced without yield penalties. However, using recovery rates as indicator ignores a possible residual effect of fertilizer N—a factor often unknown at large scales. Such residual effect might store N in the soil increasing N availability for subsequent crops. The objectives of the present study were therefore to quantify the residual effect of fertilizer N in China and to obtain more realistic rates of the accumulative fertilizer N recovery efficiency in crop production systems of China. Long-term spatially-extensive data on crop production, fertilizer N and other N inputs to croplands in China were used to analyze the relationship between crop N uptake and fertilizer N input (or total N input), and to estimate the amount of residual fertilizer N. Measurement results of cropland soil N content in two time periods were obtained to compare the change in the soil N pool. At the provincial scale, it was found that there is a linear relationship between crop N uptake and fertilizer N input or total N input. With the increase in fertilizer N input, annual direct fertilizer N recovery efficiency decreased and was indeed low (below 30% in recent years), while its residual effect increased continuously, to the point that 40%–68% of applied fertilizer was used for crop production sooner or later. The residual effect was evidenced by a buildup of soil N and a large difference between nitrogen use efficiencies of long-term and short-term experiments.
JRC Directorate:Sustainable Resources

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