Abstract:

The nonpoint source pollution has been growing to large proportion in the Taihu Lake Basin in water net plain.It was difficult to study the law of nitrogen and phosphorus loss due to their complicated characteristic.The calibrated and verificated AnnAGNPS model was applied to simulate the load of nitrogen and phosphorus from nonpoint source pollution monthly and yearly in the Taihu Lake Basin in polder area of water net plain.And then  their temporal and spatial distribution were analyzed,critical source areas were identified and the effects of best management practices to control the nitrogen and phosphorus pollution based on sensitivity analysis were evaluated.The results showed that the nitrogen and phosphorus load were 6299 t/a and 581 t/a,respectively,both with loss peaks in the summer.The loss of nitrogen and phosphorus mostly happened on slopping field and banks of river.Besides,highly fertilized areas had high nitrogen loss.Thus,it was reasonable to select the appropriate best management practices according to practical condition