Soil-vegetation Evolution Dynamics And Coupling Effects Of Different Vegetation Restoration Modes In Yushenfu Coal Mining Area

A large area of subsidence is formed after the coal is mined below the well,which causes the surface ecosystem damaged,and vegetation restoration is an important way to,restore the damaged ecosystem.For the current coal mining subsidence,there are relatively few studies about different vegetation restoration methods in different years,dynamic soil-vegetation co-succession process,and plant community ecological effects evaluation,etc.In this paper,under the artificial and natural vegetation restoration methods of coal mining subsidence sites in Yushen and on the basis of clarifying the physical and chemical properties of soil and the succession rules of plant community characteristics,the plalnt communities and soils with different recovery years(1-15 years)are taken as research objects.Firstly,the factor analysis method was used to comprehensively evaluate the soil quality and plant community quality of different vegetation restoration methods.Then the correlation analysis and redundancy analysis were used to study the relationship between soil factors and plant communities under different vegetation restoration models.Finally,the soil-plant coupling coordination model was used to discriminate the coordinated evolution characteristics of vegetation and sroil composition ecosystems under different vegetation restoration models.The results show:(1)The change of soil quality is as follows:in the initial stage of vegetation restoration(l-5a),soil bulk density,water content,organic matter,ammonium nitrogen,available phosphorus and other indicators show different degrees of reduction compared,with uncollapsed land,while soil porosity increases;With the increase of the recovery period,the soil indicators showed an overall improvement trend.After 15 years of recovery,the soil in the natural restoration plots recovered to the level before undestroy except for ammonium nitrogen and available potassium.The artificially restored plots were basically restored to the undestroyed level except for the ammonium nitrogen;at the same time,in the process of artificial and natural vegetation restoration,soil clay content,pH and total nitrogen did not change much during the whole vegetation restoration process.Through the factor analysis method,the soil quality under different vegetation restoration methods in different years indicates that the soil quality of the natural restoration 1-5 years plot is,poor,and the soil quality of the arti:ficially restored 11-15 years plot is better.(2)The succession of plant community showed that the plant community index in the initial stage of vegetation restoration(1-5a)showed different degrees of reduction compared with the uncollapsed land.With the increase of vegetation recovery time,the vegetation community structure continued to,improve until the vegetation was restored for 15 years.The plant community diversi,ty index had no significant difference compared with the non-collapsed area except the Pielou index.But the plant community diversity index of natural restoration mode has not recovered to the level before uncollapse;and under the same recovery period,the plant biomass and Margalef index under natural recovery mode are lower than the artificial recovery mode.By factor analysis,the evaluation of community structure under different vegetation restoration patterns in different years showed that the quality of soil and vegetation communities in artificially restored 11-15 years plots was superior,while the community structure quality of natural restoration 1-5 years plots was poor.(3)Correlation and redundancy analysis of soil factors and vegetation community indicators indicated that soil factors such as water,porosity and bulk density in artificial and natrural restoration plots were the main factors affecting the characteristics of vegetation communities.At the initial stage of vegetation restoration(1-5 years),the soil nitrogen was significantly affected by the plant community in the artificial vegetation restoration plot,while the soil porosity and pH in the natural restoration plot had a greater impact on the vegetation community.As the recovery period increases,the correlation between plant communities and soil factors increases gradually.Among them,soil moisture,bulk density and porosity have great influence on plant community characteristics under artificial and natural restoration methods.But the soil factor organic matter,ammonium nitrogen and available potassium only have a great influence on the artificial plant community structure.(4)The coupling of soil and vegetation under different vegetation restoration modes in the study area,except for the artificially restored 11-15 years plots,which are well-coordinated and developed vegetation-synchronized types.The rest of the restoration plots are in the category of over-development and dysfunction.Among them,the artificially restored 1-5 years plots are characterized by a barely coordinated development of vegetation-synchronous type.The natural recovery 1-5 years plot is characterized by mildly dysfunctional declining vegetation soil loss type.The artificial restoration of 6-10 years plots is characterized by primary coordinated development type vegetation lag type.The natural recovery of 6-10 years plots is characterized by the loss of vegetation types on the verge of dysfunction.The natural restoration 11-15 years plot is represented by the primary coordinated development type of vegetation soil synchronous type.