农业非点源污染物在水塘景观系统中的空间变异性研究

农业非点源污染是流域不同景观结构对降雨的一种综合响应过程，景观格局影响非点源污染物的产生和运移。本文研究安徽鲍家塘子流域中水田、秧田、水塘、荒地、沟渠等不同土地利用类型的总磷(TP)、速效磷(DRP)在土壤中的空间分布，以及降雨径流过程中TP、DRP、溶解态总磷(DTP)、悬浮物(TSS)在多水塘景观结构中的动态变化。结果表明：养分在流域不同景观组分土壤中的空间变化，是人为干扰景观异质性的综合结果；磷素输出以颗粒态磷(TP-DTP)为主，在不同景观中具有显著性差异；施肥水田是最主要的“源”景观，在降雨径流过程大量释放养分和悬浮物；水塘、荒地、没有施肥水田持留养分和悬浮物，是流域的“汇”景观，水塘有效地持留颗粒态磷；水塘系统中的沟渠是非点源污染物的主要运移通道。因此，通过对流域土地利用和景观格局的优化调整，达到对流域景观中养分过程的有效管理，实现对农业非点源污染的控制。

Spatial variability of agricultural pollutions in complicated landscape system with multiple ponds

Agricultural non-point sources pollution is the major cause of eutrophication of lake and the landscape pattern plays an important role in pollutant generation and transportation.The multiple ponds system in Baojiatang sub-watershed,located in Anhui Province,China,is used as an example to study the effect of landscape on agricultural pollution.The amounts of TP(total phosphorus)and DRP(dissolved reactive phosphorus) are used to study the spatial variability of soil nutrient in rice fields,rice seedling beds,wastelands,ditches and channels,and the amounts of TP,TRP(total reactive phosphorus),DRP,DTP(dissolved total phosphorus)and TSS(total suspended soil) in the runoff are utilized to investigate the variability of pollutant.The results show that:1.the spatial variability of soil nutrients is the comprehensive result of artificial interference and effect of heterogeneous landscapes;2.fertilizered rice fields are the most important pollution sources,whereas,the ponds,unfertilized rice fields and wastelands retain pollutants working as the sink.The channels connecting the ponds will transport the pollutants.It is concluded that by reasonably arranging the utilization of lands in river basin and optimizing the landscape patterns the nutrient in soil can be effectively managed to realize the effective control of agricultural non-point sources pollution.