EXPERIMENTAL STUDY ON THE TYPICAL INTERCEPTION EFFECT OF THE ALLOWABLE BUFFER ZONE ON THE BANK OF DONGXINKAI RIVER IN RAINWATER RUNOFF

By analyzing the impact of pollutant migration in the runoff of the vegetation buffer zone on the bank of the Dongxinkai River, the removal effect of nitrogen and phosphorus on the typical pollutants in the buffer zone on both banks was studied, and the plant configuration structure of the buffer zone was optimized. The results showed that the optimally configured vegetation buffer zone had obvious advantages over the original vegetation buffer zone in the interception effect of nitrogen and phosphorus pollutants. For the two indicators of ammonia nitrogen and total nitrogen, it had a significant reduction effect. Alfalfa plots had a reduction rate of more than 30%, 30%, and 25% for ammonia nitrogen, total nitrogen, and total phosphorus respectively, higher than other vegetation configuration plots, and had a solid root system, and relatively stronger adaptability and lower planting cost; plants had different retention effects on nitrogen and phosphorus in the buffer zone in different growth periods. The reduction rate of vegetation buffer zone in mature stage to TN and TP was 30% and 25% respectively, which was higher than that in the tillering stage. The reduction rate of nitrogen and phosphorus the was increased by more than 80%.