title: Changes in nitrogen budget and potential risk to the environment over 20years (1990-2010) in the agroecosystems of the Haihe Basin, China.
abstract: The nitrogen balance can serve as an indicator of the risk to the environment of nitrogen loss from agricultural land. To investigate the temporal and spatial changes in agricultural nitrogen application and its potential threat to the environment of the Haihe Basin in China, we used a database of county-level agricultural statistics to calculate agricultural nitrogen input, output, surplus intensity, and use efficiency. Chemical fertilizer nitrogen input increased by 51.7% from 1990 to 2000 and by 37.2% from 2000 to 2010, concomitant with increasing crop yields. Simultaneously, the nitrogen surplus intensity increased by 53.5% from 1990 to 2000 and by 16.5% from 2000 to 2010, presenting a continuously increased environmental risk. Nitrogen use efficiency decreased from 0.46 in 1990 to 0.42 in 2000 and remained constant at 0.42 in 2010, partly due to fertilizer composition and type improvement. This level indicates that more than half of nitrogen inputs are lost in agroecosystems. Our results suggest that although the improvement in fertilizer composition and types has partially offset the decrease in nitrogen use efficiency, the environmental risk has still increased gradually over the past 20 years, along with the increase in crop yields and nitrogen application. It is important to achieve a better nitrogen balance through more effective management to significantly reduce the environmental risk, decrease nitrogen surplus intensity, and increase nitrogen use efficiency without sacrificing crop yields.
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: mengmeng.zheng@163.com.
authors: Mengmeng
authors: M
authors: Zheng
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: zhenghua@rcees.ac.cn.
authors: Hua
authors: H
authors: Zheng
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Wuhan University of Technology, Wuhan 430070, China.
authors: Yingxia
authors: Y
authors: Wu
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors: Yi
authors: Y
authors: Xiao
authors: Computer Network Information Center, Chinese Academy of Sciences, Beijing 100190, China.
authors: Yihua
authors: Y
authors: Du
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors: Weihua
authors: W
authors: Xu
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors: Fei
authors: F
authors: Lu
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors: Xiaoke
authors: X
authors: Wang
authors: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors: Zhiyun
authors: Z
authors: Ouyang
mesh_terms: D000383:Agriculture; D000393:Air Pollutants; D002681:China; D017753:Ecosystem; D004785:Environmental Pollutants / Q000032:analysis*; D005308:Fertilizers / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D058458:Nitrogen Cycle; D018570:Risk Assessment; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D004785:Environmental Pollutants; D005308:Fertilizers; D009584:Nitrogen
keywords: Agroecosystem; Environmental risk; Haihe Basin; Nitrogen budget; Nitrogen surplus intensity; Nitrogen use efficiency