Closing the N-Use Efficiency Gap to Achieve Food and Environmental Security

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• 作者：Zhenling Cui ; Guiliang Wang ; Shanchao Yue ; Liang Wu ; Weifeng Zhang ; Fusuo Zhang ; Xinping Chen
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：May 20, 2014
• 年：2014
• 卷：48
• 期：10
• 页码：5780-5787
• 全文大小：281K
• 年卷期：v.48,no.10(May 20, 2014)
• ISSN：1520-5851

文摘

To achieve food and environmental security, closing the gap between actual and attainable N-use efficiency should be as important as closing yield gaps. Using a meta-analysis of 205 published studies from 317 study sites, including 1332 observations from rice, wheat, and maize system in China, reactive N (Nr) losses, and total N₂O emissions from N fertilization both increased exponentially with increasing N application rate. On the basis of the N loss response curves from the literature meta-analysis, the direct N₂O emission, NH₃ volatilization, N leaching, and N runoff, and total N₂O emission (direct + indirect) were calculated using information from the survey of farmers. The PFP-N (kilogram of harvested product per kilogram of N applied (kg (kg of N)^鈭?)) for 6259 farmers were relative low with only 37, 23, and 32 kg (kg of N)^鈭? for rice, wheat, and maize systems, respectively. In comparison, the PFP-N for highest yield and PFP-N group (refers to fields where the PFP-N was within the 80鈥?00th percentile among those fields that achieved yields within the 80鈥?00th percentile) averaged 62, 42, and 53 kg (kg of N)^鈭? for rice, wheat, and maize systems, respectively. The corresponding grain yield would increase by 1.6鈥?.3 Mg ha^鈥?, while the N application rate would be reduced by 56鈥?00 kg of N ha^鈥? from average farmer field to highest yield and PFP-N group. In return, the Nr loss intensity (4鈥?1 kg of N (Mg of grain)^鈭?) and total N₂O emission intensity (0.15鈥?.29 kg of N (Mg of grain)^鈭?) would both be reduced significantly as compared to current agricultural practices. In many circumstances, closing the PFP-N gap in intensive cropping systems is compatible with increased crop productivity and reductions in both Nr losses and total N₂O emissions.