Evolvement Mechanism And Evaluation Of Soil Quality In Vegetation Restoration Area Of Phosphorite Mining Wasteland

For soil quality variation of vegetation restoration area of Kunyang Phosphorite mining wasteland and how to evaluate of soil quality, the study based on abandoned land of Phosphorite mining wasteland in different vegetation restoration of the soil as the research object, using the method of time and space to each generation, recovery of the mine plantation vegetation plots soil quality of the physical, chemical and biological indicators characteristics Determination of the system, reveal their temporal variation and influencing factors, build soil quality evaluation index system and evaluation model, designed to provide basic data and the theoretical basis to maintain and improve on phosphate mining wasteland vegetation to restore soil productivity. Main conclusions are as follows:1. Investigated the species diversity situation.In the early stages of vegetation restoration communities not yet stable, the diversity index no obvious pattern, forest in3a vegetation recovery Alnus neaplensis+Cuperssus torulosa+Cupressus lusitanica diversity index was significantly higher than the other two communities over time the passage of time, increased species of forest vegetation recovery trend is not obvious, but the quality of species composition in improving in addition to the outside3a vegetation restoration Alnus neaplensis+Cuperssus torulosa+Cupressus lusitanica,2a, la the vegetation restoration forest and3a vegetation recovery Simpson (D) and the Shannon-Winener (H ’) increased over time.2. Studied the characteristics variation of soil properties in different restoration years.Initial recovery, soil porosity and capillary porosity overall increase; With the increase of years of recovery, soil bulk density greatly reduced compared with controls, soil moisture and pH values at first increase and then decrease phenomenon; Total nitrogen and nitrogen content of total the trend is to reduce and then increase; total phosphorus and available phosphorus, total potassium and available potassium tended to increase; organic matter presents an increasing trend. According to soil nutrient evaluation standard, soil bulk density, total porosity, pH value were weak variability; Organic matter, effective phosphorus were strong variability of fertility factor, coefficient of variation were larger, uneven distribution; Alkaline hydrolysis nitrogen, total nitrogen, total phosphorus, available potassium for medium fertility factors, the variation of coefficient of variation were relatively small; Total potassium as weak variation, relative distribution more uniform; Lack of organic matter content in the experimental area in ups and downs was bigger, total nitrogen, alkali-hydrolysable nitrogen content belong to the lack of and the lack of total phosphorus and phosphorus, total potassium and available potassium content were extremely rich. Science of soil fertility-control system should be established based on these actual situations, to improve the basis of the level of soil management, to improve the conditions of plant growth, and better promote the restoration of plant growth in mining wasteland. Vegetation restoration promoted the growth of the soil microbial community, also stimulate the beta-glycosidase enzymes in soil, unease and acid phosphatase activity; Nematode density increased gradually; Cluster analysis showed that short-term fix Oa,1a and2a form a first set of clusters,3a and4a form second groups of cluster, restore the long5a and10a form third cluster.3. Discussed the relationship between soil properties.Property indicators of soil properties, species diversity was significantly (P≤0.05) and highly significant correlation (P≤0.01) levels; The canonical correlation analysis results showed, the conversion function established between soil each attribute index, physical properties was plays a main role in soil bulk density, porosity and capillary porosity, chemical properties was plays a main role in organic matter, alkali-hydro nitrogen, rapidly-available potassium and phosphorus effectively, biological properties index was plays a main role in microbial biomass carbon (MBC), microbial biomass n (MBN), p-glycosidase enzymes and urease. They provide a reference for further screening soil quality evaluation.4. Evaluation of soil quality.Institute comprehensive evaluation index of19selected sensitivity classification study and principal component analysis, sensitivity analysis of the correlation between soil properties indicators and indicators, selected eight indicators as key indicators of soil quality. In the process of vegetation restoration, increased SQI with the years of vegetation restoration, a function relationship exists significant between the two. The vegetation growth status in field survey saw consistent, with the extension of fixed number of year of the recovery, the soil quality has very obvious, namely the vegetation recovery and soil quality are positive effect. In addition, integrated soil quality index to recover the vegetation were higher than the control, show that the vegetation restoration significantly improved the soil quality.