Effect of wheat-maize straw return on the fate of nitrate in groundwater in the Huaihe River Basin, China
Effect of wheat-maize straw return on the fate of nitrate in groundwater in the Huaihe River Basin, China
复制标题
小麦-玉米秸秆还田对淮河流域地下水硝酸盐去向的影响
DOI：
10.1016/j.scitotenv.2017.03.029
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发表时间：
2017-08-15
影响因子：
9.8
通讯作者：
Liu, Congqiang
中科院分区：
文献类型：
--
作者：
Li, Rongfu;Ruan, Xiaohong;Liu, Congqiang
秸秆还田正成为世界范围内处理农作物残渣的常规做法。然而，这种操作对当地地下水化学成分的潜在影响还没有得到很好的记录。对小麦-玉米秸秆还田区浅层地下水进行了分析，测定了地下水中硝酸盐浓度、NO(3)(-)和H2O沿两条径流路径的季节变化。地下水中D值和O-18值的测定表明地下水主要由大气降水补给，而硝态氮中的D15N和O-18值则表明地下水中NO3-的来源包括尿素、土壤氮素和污水/粪便。NO(3)(-)浓度的降低与秸秆还田地下水中有机质的富集化相一致，揭示了有利于硝酸盐还原的环境条件，而沿水流路径的增量N-15-NO(3)(-)和增量O-18-NO-3-表明发生了反硝化作用。进一步的分析表明，与不秸秆还田相比，秸秆还田枯水期和丰水期地下水硝态氮的去除分别高达80%和90%，表明秸秆还田对地下水水质具有潜在的积极作用。(C)2017爱思唯尔B.V.保留所有权利。
Straw return is becoming a routine practice in disposing of crop residues worldwide. However, the potential effect of such operation on the chemistry of local groundwater is notwell documented. Here, shallowgroundwater in an area where wheat-maize straw return is practiced was analyzed, and the seasonal changes in the nitrate concentration and the isotope compositions of NO(3)(-)and H2O were determined along two flow paths. Measured delta D and delta O-18 inwaters indicated that the groundwater wasmainly recharged by atmospheric precipitation, while measured d15N and delta O-18 in nitrate suggested that the sources for groundwater NO3-included urea fertilizer, soil nitrogen, and sewage/manure. Reduced NO(3)(-)concentrations coincided with an enrichment of organic matter in the groundwater of the strawreturn area, revealing an environmental condition that facilitates nitrate reduction, whereas increased delta N-15-NO(3)(-)and delta O-18-NO3- along the flowpath suggested the occurrence of denitrification. Further analyses showed that, compared to the cases in the absence of straw return, as much as 80% and 90% of groundwater nitrate was removed in lowand high water seasons in the strawreturn area, pointing to a potential positive effect of straw return to groundwater quality. (C) 2017 Elsevier B.V. All rights reserved.