In-Season Root-Zone N Management for Mitigating Greenhouse Gas Emission and Reactive N Losses in Intensive Wheat Production

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• 作者：Zhenling Cui ; Shanchao Yue ; Guiliang Wang ; Fusuo Zhang ; Xinping Chen
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：June 4, 2013
• 年：2013
• 卷：47
• 期：11
• 页码：6015-6022
• 全文大小：361K
• 年卷期：v.47,no.11(June 4, 2013)
• ISSN：1520-5851

文摘

Although both the grain yields and environmental costs of nitrogen (N) fertilization are gaining more public and scientific debate, the complex linkages among crop productivity, N application rate, environmental footprints, and the consequences of improved N management are not well understood. We considered the concept of linking greenhouse gas (GHG) emission, reactive N losses, and N fertilizer application rates with crop productivity to determine the response of the GHG emission and reactive N losses to N surplus and further evaluated the potential to reduce these N environmental footprints by in-season root-zone N management. A meta-analysis suggested an exponential increase in the response of direct N₂O emissions and nitrate leaching to an increasing N surplus, while NH₃ volatilization increased linearly with an increasing N application rate for intensive wheat production in north China. The GHG emission and reactive N losses during N fertilizer application increased exponentially with an increasing N surplus. By pooling all 121 on-farm experimental sites, an in-season root-zone N management strategy was shown to reduce the N application rate by 61% from 325 kg N ha^鈥? to 128 kg N ha^鈥? compared to the farmers鈥?N practice, with no loss in wheat grain yield. As a result, the intensity of GHG emission and reactive N losses were reduced by 77% and 80%, respectively. The intensity of GHG emission and reactive N losses can be further reduced due to the improved N recovery and increased grain yield achieved by best crop management. In conclusion, N recovery efficiency and yield improvements should be used to reduce future agricultural N environmental footprints, rather than reducing the N application rate.