Optimization Of Vegetation Restoration Modes In Mining Waste Lands In Beijing Fangshan District

In this study,the vegetation restoration status of 15 abandoned mining areas that have been treated in Fangshan District of Beijing was studied.The field survey included on-site ecological environment,vegetation status,soil and indoor measurement and analysis of soil samples.This survey has a total of 35 arbor plots,120 shrubs,and herbaceous plots.Based on the characteristics of vegetation community and soil physical and chemical properties,principal component analysis and correlation analysis were used to establish an evaluation index system to comprehensively evaluate the vegetation restoration model,and to select a better vegetation restoration model.According to the discussion of the factors affecting the survival rate,aiming at the treatment of abandoned mines in Fangshan District of Beijing,a better vegetation restoration model and corresponding key technical systems were proposed.There were 10 plantation restoration modes in the study area,including platycladus orientalis pure forest,pinus tahulaeformis pure forest,Acer truncatum Bunge and pinus tabulaeformis mixed forest,Juglans regia L pure forest,Armeniaca sibirica pure forest,Acer truncatum Bunge pure forest,Populus L pure forest,Salix babylonica pure forest,Acer truncatum Bunge and platycladus orientalis mixed forest,and Cotinus coggygria Scop pure forest.The research results are as follows:1.Community characteristics and soil physical and chemical properties under different vegetation restoration modes(1)there were differences in survival rates among different recovery models,with the highest survival rate of platycladus orientalis pure f orest and Armeniaca sibirica pure forest at 98%and the worst survival rate of Cotinus coggygria Scop pure forest at 56%.The canopy density of each stand was between 13%and 58%,the highest was 58%of Armeniaca sibirica pure forest canopy density and the lowest was 13%of Populus L pure forest canopy density.(2)The plant diversity of each community has improved.The 10 models of the Margalef index are the highest in Populus L pure forest are 1.16,and the lowest in Salix babylonica pure forest are 0.58.The Simpon index and the Pielou evenness index are the highest in the side of platycladus orientalis pure forest,respectively,0.73,0.88,the lowest in Cotinus coggygria Scop,respectively,0.29,0.44,the Shannon-Wiener index,the highest in the pinus tabulaeformis pure forest,1.45,and the lowest in the Juglans regia L,0.64.(3)Soil bulk density ranged from 1.23g/cm3 to 1.69g/cm3,soil moisture content ranged from 13%to 32%,total porosity from 38%to 50%,and saturated moisture content from 23%to 41%.According to statistics,The effect of platycladus orientalis pure forest and pinus tabulaeformis pure forest on soil improvement was better.(4)the significant change range of soil PH value was 7.65-8.91.The organic content ranged from 0.24%to 1.07%.Total nitrogen content ranged from 0.21 to 0.76g/kg.The content of available potassium was 63.2-302mg/kg.Available phosphorus content ranged from 1.41 to 13.8mg/kg.The comprehensive analysis showed that the soil PH values of the abandoned mining areas were all alkaline,and the difference of 10 planting cover recovery models was not significant.The content of organic matter was very low,and the soil nutrient elements were in the stage of deficiency,but the content of each element in the 0-20cm layer was higher than that in the 20-40cm layer.2.Comprehensive evaluation of different vegetation restoration modesThe results of evaluation of 10 plant restoration patterns were as follows:platycladus orientalis pure forest>pinus tabulaeformis pure forest>Acer truncatum Bunge and pinus tabulaeformis mixed forest>Juglans regia L pure forest>Armeniaca sibirica pure forest>Acer truncatum Bunge pure forest>Populus L pure forest>Salix babylonica pure forest>Acer truncatum Bungeplatycladus orientalis mixed fores>Cotinus coggygria Scop pure forest.3.Vegetation recovery modes optimization and key technology researchThe best mode of the three sides of the comprehensive evaluation of the side of platycladus orienalis pure forest?pinus tabulaeformis pure forest?Acer truncatum Bunge and pinus tabulaeformis mixed forest,By discussing the effects of soil substrate technology,plant allocation technology and plant planting technology on the survival rate of vegetation and the later maintenance and management of vegetation restoration,the restoration mode and corresponding key technologies are proposed.According to the actual situation,choose cavern or fish-scale pit.The thickness of overlaying soil was more than 30cm for platycladus orientalis,and more than 40cm for pinus tabulaeformis and Acer truncatum Bunge.Community structure with combination of arbor,shrub and grass in regions with better soil condition;Platycladus orientalis and Pinus tabulaeformis Carr should be in the range of 1.0-1.5m and Acer truncatum Bunge should have a DBD of about 2cm..The row spacing of the platycladus orientalis should be 2m×2m,the pinus tabulaeformis should be 2m×3m,and the Acer truncatum Bunge should be 2m×3m..Water conservation techniques are used;Ensure the later management and maintenance.