珠江三角洲典型流域AnnAGNPS模型模拟研究

针对珠江三角洲地区地表水体日益突出的氮、磷富营养化问题，选择新田小流域为主要研究对象，应用GIS技术和AnnAGNPS模型，对流域出口及重要景观单元出口的径流量、总氮和总磷进行同步观测和模拟估算。结果表明：（1）AnnAGNPS模型具有较好的模拟效果，在径流量、总氮和总磷的模拟估算中，最小模拟偏差为1.4%，最大模拟偏差为34.34%，模拟值与实测值之间具有很好的相关性;（2）在所观测的4场降雨中，模拟效果受雨量的影响较为明显，在一定范围内，雨量越大，模拟效果越好，雨量越小，模拟效果越差;（3）不同景观单元由于下垫面性质及其人类活动强度大小影响的不同，模拟效果也表现出一定的差异，果园＋林地景观单元模拟效果最好，而水田＋旱地景观单元模拟偏差较大;（4）水田＋旱地景观单元总氮、总磷污染负荷比重大，是农业非点源污染来源的主要类型和关键源区，这一结果可为区域非点源污染控制和管理提供决策支持。

AnnAGNPS Modeling of Agricultural Non-point Source Pollution in the Typical Watershed of Pearl River Delta

AnnAGNPS model and GIS were applied to predict the export of runoff,nitrogen and phosphorus from Xintian watershed,a representative catchment in the Pearl River Delta,with a serious problem of eutrophication.The results showed that:(1) AnnAGNPS model could better simulate the export of runoff,total nitrogen(TN) and total phosphorus(TP) with the minimal deviation 1.4% and the maximal deviation 34.34%;(2) The simulation effect was affected apparently by rainfall,and within 4 observed rains,the more rainfall the better simulation effect,the less rainfall the worse simulation effect;(3) The simulation effect varied with the diversity of the earth surface,different landscapes and human activities,with the better effect for orchard and forest landscape,but worse effect for paddy field and dry land landscape;(4) The paddy field and dry land landscape was the critical source of agriculture non-point source pollution because of the higher load proportion of TN and TP.These results will be useful for controlling and managing non-point source pollution.