中文关键词多水塘系统非点源污染氮截留农村流域景观结构 英文关键词multi-pond systemnon-point source pollutionnitrogen retentionagricultural watershedlandscape structure

作者	单位	E-mail
李玉凤	南京师范大学海洋科学与工程学院, 南京 210023	pandalee_0826@163.com
刘红玉	南京师范大学海洋科学与工程学院, 南京 210023
刘军志	南京师范大学地理科学学院, 江苏省地理信息资源开发与利用协同创新中心, 江苏省地理环境演化国家重点实验室培育建设点, 南京 210023
娄彩荣	南京师范大学地理科学学院, 江苏省地理信息资源开发与利用协同创新中心, 江苏省地理环境演化国家重点实验室培育建设点, 南京 210023
王娟	南京师范大学地理科学学院, 江苏省地理信息资源开发与利用协同创新中心, 江苏省地理环境演化国家重点实验室培育建设点, 南京 210023

中文摘要 多水塘系统在滞留和降解农业面源污染中发挥着巨大作用.不同景观结构特征的多水塘系统对农业面源污染的截留率也存在差异.本文针对多水塘系统的功能及特点，选择4个不同景观结构的小流域作为研究区域，分析降雨前后多水塘系统水环境的变化特征及其对氮元素的截留情况，并揭示其截留率与水塘系统景观结构之间的关系.结果表明：①雨前水塘水体中总氮（TN）浓度的变化范围在1.32~6.32 mg·L^-1之间，雨后TN质量浓度增加到2.8~16.99 mg·L^-1之间，其中，硝氮（NO₃^--N）占TN的质量分数为20%~74%；②多水塘系统对TN、NO₃^--N和氨氮（NH₄⁺-N）的平均截留率分别为50.09%、48.71%和52.75%；③小流域1中的水塘系统对氮的截留率最低，平均次降水过程中小流域2中的水塘系统对氮的截留量最低，仅为56.10kg，远低于小流域4中水塘系统对氮的截留量324.43kg；④多水塘系统对氮的截留率受到水塘个数、面积及水塘与水塘之间沟渠密度的影响，其中沟渠密度对氮截留率的影响最大.本研究结果可为农村多水塘系统的管理及规划提供科学依据. 英文摘要 Nitrogen (N) loss from agricultural fields can cause eutrophication in downstream freshwater systems, but the use of multi-pond networks can mitigate N losses from agricultural runoff. This study presents an analysis of the relationships between N retention and land use before and after rainfall events with the goal of identifying differences in agricultural runoff in four sub-watersheds with 3, 3, 7, and 7 ponds, respectively. The total N concentrations before rainfall ranged from 1.32 mg·L^-1 to 6.32 mg·L^-1, and total N (TN) levels in the ponds after rainfall varied from 2.8 mg·L^-1 to 16.99 mg·L^-1 and typically contained 20%-74% nitrate (NO₃^--N). The mean concentration retention efficiencies in the four sub-watersheds for TN, NO₃^--N, and ammonium (NH₄⁺-N) were 50.09%, 48.71%, and 52.75%, respectively. The N retention efficiency in sub-watershed 1 (3 ponds) was the lowest among the four sub-watersheds. The N retention mass in sub-watershed 2 (3 ponds) was only 56.10 kg, and this value was far lower than that of sub-watershed 4 (324.43 kg, 7 ponds). The number of ponds in the sub-watersheds was not the only factor that contributed to the effective retention of non-point source N in-situ, but pond area and ditch density also significantly affected N retention. Thus, pond area and ditch density should be increased for similar multi-pond areas. However, managing multi-ponds to maximize N retention requires dynamic monitoring and management over the long term.

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