Seasonal Variations of Soil Microbial Communities on Sloping-Land with Purple Soils

Seasonal variations of soil microbial communities in surface soil(0~10 cm) of Robinia pseudoacacia natural secondary forest on sloping-land with purple soils in Hengyang city of Hunan province, south-central China was studied by using the method of dilution-plate method and Biolog ECO-microplate culture. The results showed that:(1)The quantity of soil microorganism, bacteria, fungi and actiomycetes was the maximum in summer, they was 16.34×106, 16.09×106, 10.43×104 and 14.64×104 cfu·g-1 dry soil, respectively, fewer in spring, 11.61×106, 11.45×106, 5.00×104 and 10.65×104 cfu·g-1 dry soil, respectively, the minimum in autumn, 5.87×106, 5.78×106, 4.67×104 and 4.08×104 cfu·g-1 dry soil, respectively, there existed significantly difference among the microbe quantity of three seasons(P0.05);(2)The peak value of AWCD(Average well color development) was found in summer(1.20), followed by spring(0.88) and autumn(0.83) in consequence;(3)The microbial functional diversity was significantly higher in summer than in spring and autumn(P0.05), and showed no significant difference in spring and autumn(P0.05), for summer, Patrick richness index(R)(28), Shannon-Wiener index(H)(3.22), Simpson index(D)(0.96) and Mc Intosh index(U)(8.20), for spring and autumn, R(23, 24), H(3.06, 3.08), D(0.95, 0.95) and U(5.90, 5.91);(4)Amino acids, ployers and carboxylic acids were the main C sources utilized by the microbial communities;(4)PCA(Principal component analysis) showed the C sources by soil microbes were divided into two categories, one in summer, another, spring and autumn, the range of score coefficient were(2.59_ 6.00, 2.43_ 5.09) and(-7.65_-1.90,-6.38_-3.43), respectively. Above all, this result would provide more important primitive properties of microbial features in the degradation and restoration process of the quality of the soil habitat scientifically on the sloping-land with purple soils in Hengyang of Hunan Province, South-central China.