POLLUTION FROM AGRICULTURAL NON POINT SOURCES AND ITS CONTROL IN RIVER SYSTEM OF TAIHU LAKE, JIANGSU
苏南太湖水系农业面源污染及其控制对策研究

A concept of net pollutant load was developed and applied to study the network of flooded rice fields covering an area from 15000 to 25000m 2 in Taihu Lake regions, Jiansu.The experimental area covers seven types of rice and dry land.With the help of 15 N tracing technique,the loss of nitrogen was studied both in field and in laboratory.The results show that the load of nitrogen from agricultural non point sources increase as the rise of the annual rainfall and the irrigation. The load of nitrate to shallow groundwater increases as increased application of nitrogenous fertilizer. The load of nitrogen to the rice field is much higher than that to upland.There is a negative correlation between the net load of phosphorus from agricultural non point sources and phosphorus content in the irrigation water. The total load of nitrogen and phosphorus from agricultural non point sources in the Taihu lake region in southern Jiansu was calculated.