Suitable Buffer Strip Width along Rivers for Nitrate N Removal from Paddy Field Drainage

摘要

The buffer strip play an important role in removal non-point source pollution and improvement of the water quality of the river. Nitrate N in paddy field drainage can lead to the soil and underwater pollution caused the eutrophication of rivers too. Based on discussing of the function of buffer strips and the removal mechanism of nitrate nitrogen, the mathematical model for simulation of solute transport and the suitable width in buffer strips was established, the model accuracy was validated by thefield experiment data. The distribution of nitrate nitrogen concentration in buffer alfalfa strips under different paddy field drainage conditions was calculated, and the buffer strips width was confirmed. The results showed that when the nitrate nitrogen concentration of paddy drainage is 10mg/l, the suitable minimum width of buffer alfalfa strips is 7.3m, for 20mg/lis 15.0m for the removal rate of nitrate nitrogen in buffer strips reached 90%.