我国东部典型农业流域河流氮输出对人类活动和气象因子的响应  

Response of riverine nitrogen export to human activities and meteorological factors in a typical agricultural watershed of eastern China

作　　者：郝韵 吕军[1] HAO Yun;LÜJun(Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health,College of Environmental and Resource Sciences,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学环境与资源学院,污染环境修复与生态健康教育部重点实验室,杭州310058

出　　处：《浙江大学学报（农业与生命科学版）》2022年第5期605-613,共9页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：国家自然科学基金项目(41977006);国家重点研发计划项目(2016YFD0801103)。

摘　　要：非点源氮污染是农业流域水质退化的主要环境风险之一。本研究通过对2003—2016年浙江省嵊州市长乐江流域净人为氮输入量(net anthropogenic nitrogen input,NANI)和河流出口断面氮输出量的监测,探究河流水质对NANI和驱动非点源污染的气象因子的响应关系,并建立响应模型以分析河流氮的污染源。结果表明:2003—2016年,该流域NANI均值为95.77 kg/(hm^(2)·a),其中施肥、净人类食品和畜禽饲料、大气氮沉降、生物固氮和种子氮的输入氮量均值分别为53.90、25.62、11.94、4.18、0.13 kg/(hm^(2)·a)。流域内河流氮平均输出量为2178.78 t/a;河流氮输出与流域NANI和降水量呈正相关,与蒸发量和风速呈负相关。响应模型(R2=0.8010,纳什效率系数=0.7991)的模拟结果表明,流域内的历史遗留氮、当年NANI和河流背景氮分别占河流氮输出总量的66.8%、30.8%、2.4%。流域内的历史遗留氮不仅是河流氮污染的最大贡献者,还会长期影响河流水质,这说明河流水质对流域氮减排措施的响应具有明显的滞后效应。因此,实施长期的控氮措施是防治农业流域河流氮污染的重要策略。Non-point source nitrogen(N)pollution is one of the major environmental threats of water quality degradation in agricultural watersheds.Based on the monitoring data of N output at riverine outlet section and the calculation of net anthropogenic nitrogen input(NANI)in the Changle River watershed of Shengzhou City,Zhejiang Province from 2003 to 2016,the response relationships of riverine water quality to NANI and meteorological factors driving non-point source pollution were explored,and a response model was established to evaluate riverine N pollution sources in this study.The results showed that,during the study period,the average NANI was 95.77 kg/(hm^(2)·a),among which chemical fertilizer N,net human food and animal feed N,atmospheric N deposition,biological N fixation and seed N contributed 53.90,25.62,11.94,4.18 and 0.13 kg/(hm^(2)·a),respectively.The average riverine N export was 2178.78 t/a,which was positively correlated with NANI and precipitation,and negatively correlated with evaporation and wind speed in the studied watershed.Accordingly,the simulated results of the response model[R2=0.8010,Nash-Sutcliffe efficiency coefficient(NSE)=0.7991]showed that the historical remained N in the watershed,the NANI of the current year and the riverine background N accounted for 66.8%,30.8%and 2.4%of the riverine N export,respectively.These results indicated that the historical remained N in the watershed was the largest contributor to riverine N pollution with a long-term impact on riverine water quality,which implied the existence of lag effect of riverine water quality in response to the measures of N emission reduction in the watershed.Therefore,the implementation of long-term N control measures should be an important strategy to prevent and control riverine N pollution in agricultural watershed.

关 键 词：净人为氮输入 非点源污染 河流氮输出 气象因子 响应模型 

分 类 号：X522[环境科学与工程—环境工程]