污染负荷及植被生物量变化对缓冲带污染物净化效果的影响

模拟上海地区农业面源污染和降雨特征，进行缓冲带污染物净化效果和植被生物量监测试验研究。结果表明：植被缓冲带对径流污染物质的净化效果明显高于空白对照，百慕大缓冲带SS截留率最高，达到74％；白花三叶草对TN、TP的净化效果最好，去除率分别为28％和25％；百慕大和白花三叶草生物量最大，栽种当年9月份，两者地上部分的生物量鲜重分别达到了6.14和6.49 kg/m²，百慕大生长速度最快，当年9月份生物量几乎达到5月份的6倍；植被生物量增长明显提高了缓冲带截留径流污染物的效果，缓冲带SS截留率与生物量成显著线性相关，而污染负荷变化对缓冲带污染物净化效果的影响很小，明显弱于植被种类和生物量的变化。

Effects of pollutant loads and vegetation biomass of buffer strips on runoff purification

A series of experiments of runoff pollution purification and biomass of buffer strips were conducted with the simulation of the characteristics of agricultural area pollution and rainfall in Shanghai. Results showed that the purification efficiency to runoff of sward buffers was significantly better than the blank control, the suspended solid (SS) average retention rate of Cynodon dactylon buffer strip was the highest, up to 74%; the total nitrogen(TN) and total phosphorus (TP) average removal rate of Trifolium repens buffer strip was the highest, up to 28% and 25%; in September, the aboveground biomass of C. dactylon was 6.14 kg/m², and T. repens was 6.49 kg/m2, higher than the other species; the growth rate of C. dactylon was the fastest, whose biomass in September was almost six times of which in May; the purification efficiency of the sward buffers was increased with the higher biomass, there was a significant linear correlation between sward biomass and SS retention efficiency, but there was almost no effect between pollutant loads and purification efficiency, which was significantly less than the effect between sward type and biomass and purification efficiency.