不同草本缓冲带对径流污染物滞留效益及其最佳宽度研究

Effects of Different Grass and Width of Riparian Buffer Strips on Runoff Purification

为营建河岸缓冲带提供依据,研究了冰草、高羊茅、披碱草、紫花苜蓿4种草皮缓冲带对渗流水中总氮、总磷的净化效果。结果表明,4种缓冲带对总氮的平均去除率在60%以上,冰草缓冲带的全程TN削减量最高,紫花苜蓿缓冲带的全程TN削减量最低,相差9.8个百分点。4种缓冲带对总磷的平均去除率达79.31%,高羊茅缓冲带对TP的削减率最高,紫花苜蓿最低,相差13.56个百分点。通过数据拟合的方法计算当总氮去除率达50%时,4种草皮缓冲带所需的最佳宽度,计算结果分别为冰草缓冲带7.17m,高羊茅缓冲带8.08m,披碱草缓冲带6.89m,紫花苜蓿缓冲带8.84m。

Field test data collected were employed to compare the effectiveness of four sward riparian buffer zones for reduction of nutrients in the leachate.Results showed that an average TN removal rate of the four sward buffer zones was over 60%.Agropyron was the best responsible for 69.91% TN reduction.Alfalfa was the worst responsible for 60.11% TN reduction.the four sward buffer zones achieved an average TP removal of 79.31%.Festuca was the best responsible for 84.87% TP reduction.Alfalfa was the worst responsible for 71.31% TP reduction.Field test data collected over the 5-month period in 2009 were employed to estimate the buffer zone width for achieving 50%TN reduction.Results showed that Agropyron riparian buffer zone was 7.17 m;Festuca riparian buffer zone 8.08 m;Elymus riparian buffer zone 6.89 m;Alfalfa riparian buffer zone 8.84 m.