滇池流域退耕区植物群落构建对地表径流污染物的削减效应

为探索不同群落的构建在滇池流域的实际应用,以确定削减污染物最优植物群落的配置方式,该研究选取地表径流悬浮物(SS)、COD含量、总氮(TN)、总磷(TP)、氨氮(NH_4~+-N)、硝氮(NO_3~--N)六个指标作为主要的分析对象,在滇池流域退耕区开展了不同植物群落配置对地表径流污染物削减效应的试验研究。结果表明:三个植物群落对SS、COD、TN、TP、NO_3~--N在2014年和2015年间均表现出显著性的削减趋势,且三个植物群落对SS、TP和NO_3~--N的削减率均在45%以上,但并未对NH_4~+-N表现出削减效果。不同植物群落对污染物的削减效应存在一定的差异性,但是三个不同群落与年度的交互作用对SS、COD、TN、TP、NO_3~--N五个养分指标的削减并没有表现出显著的差异性。从整体上来看,三种植物群落类型中,以乔-灌-草构建的立体式植物群落对地表径流污染物的削减效果最佳。

Effects of plant community establishment on surface runoff pollutant reduction of abandoned farmland area in Dianchi Lake basin

Dianchi Lake basin is the largest shallow water lake on the Yunnan-Guizhou Plateau. It is crucial to maintain the ecological and environmental sustainable development of Yunnan Province. In the present study, three different plant communities were established in Dianchi Lake basin to analyze the effects of plant community on the surface runoff pollutant reduction of abandoned farmland area. The experiment aimed to explore the practical application and determine the optimal configuration of plant communities in reducing pollutants in Dianchi Lake basin. Six indictors which include suspended solids(SS), chemical oxygen demand(COD), total nitrogen(TN), total phosphorus(TP), ammonia nitrogen(NH₄⁺-N), nitrate nitrogen(NO₃^--N)were selected in the present study. The results showed that the indicators of SS, COD, TN, TP and NO₃^--N were siginificantly reduced between 2014 and 2015 regardless of the plant community types. The average reduction rates reached 45% for SS, TP and NO₃^--N. However, NH₄⁺-N was not effectively reduced. There were some differences to reduce the pollutant among different plant communities. However, the interaction between different communities and annual reduction for SS,COD,TN,TP,NO₃^--N did not show significant differences. It was suggested that plant species selection and their spatial allocations had great significance in the bio-treatment of polluted lakes and the ecological recovery of abandoned farmland area in Dianchi Lake basin. On the whole, it can be conclude that the plant community of arbor-shrub-herb has the best effects on reducing pollutants of surface runoff in Dianchi Lake basin. Therefore, we suggest that the plant community of arbor-shrub-herb should be prioritized application in the ecological restoration and recovery of Dianchi Lake basin. This study on the plant community establishment and its effect on surface runoff pollutant reduction in abandoned farmland area of plateau lake can provide scientific information for nonpoint pollution control, ecological restoration and recovery.