水土保持措施对京郊板栗林地水土流失及面源污染的影响OA

[Objective]This study aims to investigate the impact of soil and water conservation measures on soil erosion and non-point source pollution,to elucidate the effectiveness of different management measures,and to provide a scientific basis for selecting optimised measures that balance the improvement of the agricultural ecological environment with the economic benefits for farmers.[Methods]Taking the Castanea mollissima forest in Miyun District of Beijing as the research object,three vegetation measures,five engineering measures,and seven combined vegetation-engineering measures were designed to analyze the effects of different soil and water conservation measures on soil erosion and non-point source pollution,and to compare the efficacy of various measures in reducing runoff and sedimentation,as well as mitigating non-point source pollution.The study further aimed to reveal the relationship between runoff and sediment reductions and the mitigation of non-point source pollution.[Results](1)In terms of reducing runoff and sediment,among single vegetation measures,Selaginella tamariscina had better effect on runoff and sediment reduction compared with Cynodon dactylon and Lolium perenne,and its runoff and sediment reduction rates were 60.58%and 84.77%;among single engineering measures,contour trenches had better effect on runoff and sediment reduction compared with eco-bag,fish-scale terrace+mulch,and fish-scale terrace,and its runoff and sediment reduction rates were 77.66%and 94.84%.Among combination measures,the erosion control bio-blanket and vegetation combination treatment outper-formed the other combinations in terms of runoff and sediment reduction,with runoff reduction rates of over 90%and sediment reduction rates of almost 100%.(2)Among single vegetation measures,S.tamariscina had the best effect in reducing non-point source pollution,with the reduction rates of Total Nitrogen(TN),Ammonia Nitrogen(NH3-N),Total Phosphorus(TP)and Chemical Oxygen Demand(COD)being 89.07%,87.27%,89.46%and 84.82%,respectively.Among single engineering measures,contour trenches had the best effect in reducing non-point source pollution,with the reduction rates of TN,NH3-N,TP and COD being 90.96%,93.40%,95.51%and 94.13%,respectively.Among combination measures,the erosion control bio-blanket and vegetation combination treatment had a better effect in reducing non-point source pollution,with the reduction rates reaching more than 98%.(3)The runoff and sediment reduction rates showed a significant power function relationship with the reduction rates of TN,NH3-N,TP and COD(p<0.05).The correlation between the reduction rates of TP and COD and the runoff reduction rates was strong(R2>0.92),and the correlation between the reduction rates of TP and the sediment reduction rates was even stronger(R2=0.96).Different soil and water conservation measures were more effective in controlling the transport of phosphorus and organic matter by reducing runoff and sediment.[Conclusion]Vegetation and engineering combination measures are highly effective in controlling soil erosion and non-point source pollution in C.mollissima forest of Miyun District.Of these,the combination of S.tamariscina and the erosion control bio-blanket demonstrates the most effective integrated control.If economic cost is the primary consideration,S.tamariscina can be the most cost-effective soil and water conservation measure for this region.