南方地区水源塘坝保护的植被措施综合评价

Comprehensive Evaluation of Vegetative Filter Strips of Ponds and Dams in Southern China

在野外实地建立了高羊茅+小叶女贞的植被组合条件下的3种不同过滤带宽度(2、3、4 m)和过滤带宽度为3 m条件下的5种不同植被组合(高羊茅+小叶女贞、三叶草+小叶女贞、高羊毛+火棘、三叶草+火棘、高羊茅+小叶女贞+碎石覆盖)以及空白对照组共8组试验小区,监测了2017年6月-2018年3月共计5场不同强度的自然降雨(23.0~100.2 mm/h)条件下每次降雨后的出流水量、出流泥沙量、出流总氮浓度以及出流总磷浓度。结果表明,在过滤带宽度一致时,高羊茅+小叶女贞的植被配置模式净化效果最好。高羊茅+小叶女贞的植被组合过滤带的宽度为4 m时,相比于宽度为2和3 m的情况下,出流水量、出流泥沙量、出流总氮浓度以及出流总磷浓度均为最低。通过建立塘坝复合植被过滤带工程评价指标体系,分别对不同植被组合配置模式进行打分,结果表明,5种植被过滤带不同植被组合配置模式中高羊茅+小叶女贞+碎石覆盖(C5)总得分最高(91.5分),明显高于其他类型的配置模式,说明在拦沙截污、生态、经济等方面综合效果作用最好,在该研究区复合植被过滤带工程中值得优选。该研究结果可为植被过滤带技术的应用和推广提供理论依据。

Three different filter bandwidth(2,3,4 m)of the tall fescue and ligustrum microphylla vegetation combination,and five different vegetation combinations(tall fescue+Ligustrum microphylla,clover+Ligustrum microphylla,tall fescue+pyracantha,clover+pyracantha,tall fescue+Ligustrum microphylla+gravel mulch)and control group were established in the field.The outflow water,outflow sediment,outflow total nitrogen concentration and outflow total phosphorus concentration after each rainfall were measured during five different intensities(23.0-100.2 mm/h)of natural rainfall from June 2017 to March 2018.The results showed that the tall fescue combined with Ligustrum lucidum was most effective among all the tested vegetation combinations at reducing soil loss and intercepting pollutants when the filter bandwidth was the same.When the width of the combined filter belt of tall fescue and Ligustrum lucidum was 4 m,the effluent water,sediment,nitrogen and phosphorus concentration were lower than the conditions that the width was 2 m or 3 m.Through establishing an evaluation index system of the vegetative filter strips of ponds and dams,the different vegetation filter strips were scored.The results showed that the score of tall fescue combined with Ligustrum microphylla and gravel cover was significantly higher than the other four different vegetation combination allocation modes in the filtered zone.The results indicated that this filter belt had the best comprehensive effects on soil interception,ecology and economy benefits,and it deserved to be optimized in the project of the composite vegetation filter zone in the study area.This study can provide a theoretical basis for the application and popularization of vegetation filter belt technology.