Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed

	Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed
	Dong, Yue; Yang, Jin-Ling; Zhao, Xiao-Rui; Yang, Shun-Hua; Mulder, Jan; Dorsch, Peter; Zhang, Gan-Lin
刊名	ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
	2021
英文摘要	Nitrate (NO3-) loss and enrichment in water bodies caused by fertilization are a major environmental problem in agricultural areas. However, the quantitative contribution of different NO3- sources, especially chemical fertilizers (CF) and soil organic nitrogen (SON), to NO3- runoff loss remains unclear. In this study, a systematic investigation of NO3- runoff and its sources was conducted in a subtropical agricultural watershed located in Yujiang County, Jiangxi Province, China. A semi-monthly sampling was performed at the inlet and outlet from March 2018 to February 2019. Hydrochemical and dual NO3- isotope ((15) N and O-18) approaches were combined to estimate the NO3- runoff loss and quantify the contribution of different sources with a Bayesian isotope mixing model. Source apportionment by Stable Isotope Analysis in R (SIAR) suggested that NO3- in runoff was mainly derived from nitrification of ammonium (NH4+) mineralized from SON (37-52%) and manure/sewage (M&S) (25-47%), while the contribution of CF was relatively small (14-25%). The contribution of various sources showed seasonal variations, with a greater contribution of CF in the wet growing season (March to August). Compared with the inlet which contributed 37-40% to runoff NO3-, SON contributed more at the outlet (49-52%). Denitrification in the runoff was small and appeared to be confined to the dry season (September to February), with an estimated NO3- loss of 2.73 kg N ha(-1). The net NO3- runoff loss of the watershed was 34.5 kg N ha(-1) yr(-1), accounting for 15% of the annual fertilization rate (229 kg N ha(-1) yr(-1)). Besides M&S (22%), fertilization and remineralization of SON (CF + SON) were the main sources for the NO3- runoff loss (78%), suggesting accelerated nitrification of NH4+ from CF (24%) and SON mineralization (54%). Our study indicates that NO3- runoff loss in subtropical agricultural watersheds is dominated by nonpoint source pollution from fertilization. SON played a more important role than CF. Besides, the contribution of sewage should not be neglected. Our data suggest that a combination of more rational fertilizer N application (CF), better management of SON, and better treatment of domestic sewage could alleviate NO3- pollution in subtropical China.
内容类型	期刊论文
源URL	[http://159.226.73.51/handle/332005/20344]
专题	中国科学院南京地理与湖泊研究所
推荐引用方式 GB/T 7714	Dong, Yue,Yang, Jin-Ling,Zhao, Xiao-Rui,et al. Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed[J]. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH,2021.
APA	Dong, Yue.,Yang, Jin-Ling.,Zhao, Xiao-Rui.,Yang, Shun-Hua.,Mulder, Jan.,...&Zhang, Gan-Lin.(2021).Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed.ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH.
MLA	Dong, Yue,et al."Nitrate runoff loss and source apportionment in a typical subtropical agricultural watershed".ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH (2021).