环境科学
农业
反硝化
硝化作用
总有机碳
tar(计算)
溶解有机碳
氮气
水文学(农业)
环境化学
环境工程
化学
生态学
生物
岩土工程
有机化学
计算机科学
工程类
程序设计语言
作者
Xiaobing Yan,Haojie Han,Jie Qiu,Li Zhang,Yongqiu Xia,Xiaoyuan Yan
出处
期刊:Water Research
[Elsevier]
日期:2022-07-01
卷期号:220: 118639-118639
被引量:6
标识
DOI:10.1016/j.watres.2022.118639
摘要
The effects of land use on riverine N2O emissions are not well understood, especially in suburban zones between urban and rural with distinct anthropogenic perturbations. Here, we investigated in situ riverine N2O emissions among suburban, urban, and rural sections of a typical agricultural-urban gradient river, the Qinhuai River of Southeastern China from June 2010 to September 2012. Our results showed that suburban agriculture greatly increased riverine N concentration compared to traditional agricultural rivers (TAR). The mean total dissolved nitrogen (TDN) concentration was 8.18 mg N L-1 in the suburban agricultural rivers (SUAR), which was almost the same as that in the urban rivers (UR, of 8.50 mg N L-1), compared to that in TAR (0.92 mg N L-1). However, the annual average indirect N2O flux from the SUAR was only 27.15 μg N2O-N m-2 h-1, which was slightly higher than that from the TAR (13.14 μg N2O-N m-2 h-1) but much lower than that from the UR (131.10 μg N2O-N m-2 h-1). Moreover, the average N2O emission factor (EF5r, N2O-N/DIN-N) in the SUAR (0.0002) was significantly lower than those in the TAR (0.0028) and UR (0.0004). The limited indirect N2O fluxes from the SUAR are best explained by the high riverine dissolved organic carbon (DOC) and low dissolved oxygen, which probably reduced the denitrification source N2O by favoring complete denitrification to produce N2 and inhibited the nitrification source N2O, respectively. An exponential decrease model incorporating dissolved inorganic nitrogen and DOC could greatly improve our EF5r predictions in the agricultural-urban gradient river. Given the unprecedented suburban agriculture in the world, more studies in suburban agricultural rivers are needed to further refine the EF5r and better reveal the mechanisms behind indirect N2O emissions as influenced by suburban agriculture.
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