Changes of soil physicochemical and microbial features during the typical vegetation restoration in karst mountain

Five types of vegetation（farmland, 1-year abandoned farmland, bush-grass land, 15-year scattered woodland（Platycladus orientalis）and 25-year woodland（Platycladus orientalis））are selected to investigate the changes of soil physicochemical and microbial features during the vegetation restoration in karst mountain. The results show that the soil improving process is complicated. Density increases first and then decreases. The trend of bulk density is just opposite to that of total porosity. Soil available water capacity in bush-grass land is the lowest. The amount of >0.25 mm soil water stable aggregate content has increased by 5.1%～12.5% in the last four stages than that in farmland, and the amount of >0.25 mm soil water stable aggregate content in the bush-grass land is the highest. Aggregate destruction ratio gradually decreases by 34.0%～64.7% from abandoned farmland to woodland with a obviously close correlation with organic matter content. The total nitrogen and available nitrogen have the same increasing trend during the vegetation restoration. The total soil microorganism decreases at first and then increases. The quantity of bacteria group is much higher compared to other two groups at every stages, which accounts for 66.7%～93.3% against the total. The bacteria group is also the most important contributor to soil respiration. The difference for soil characteristic is the result of comprehensive function of surface vegetation composition, litter composition and other different features.