DYNAMICS OF SOIL MICROBIAL PROPERTIES FOLLOWING LAND UTILIZATION TYPES IN A KARST REGION, SOUTHWEST CHINA

Land-use change can have great influences on soil conditions and microbes are likely respond to these changes. However, such responses are poorly characterized as few studies have examined how changes in soil microbes do, or do not, correlate with environmental factors across land-use types. Soil microbial, conventional, and mineral properties and vegetation were investigated and analyzed under farmland, grassland, brush, plantation forest, secondary forest, and primary forest in the karst region of southwest China. Soil main microbial populations varied among land-use types, total populations were large in the primary forest and farmland, and low in the plantation forest. The three forests had a higher proportion of bacteria, and other types had a higher proportion of actinomycetes, while all the types had a low proportion of fungi. Soil microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP) were highest in primary forest. Only MBC and microbial populations had a perfect fractal relationship. MBC had closest relationships with Shannon index in tree layer and TN, Fe2O3, and CaO. Soil microbial biomass was high, while microbial status was perfect in the primary forest. Microorganisms were significantly correlated with vegetation, soil nutrients, and minerals following land utilization types in the karst region of China.