Characteristics of microbial quantities and communities in forest soils of Jinyun Mountain

In present research work, Phyllostachys pubescen forest, coniferous forest of Pinus massoniana, and needle leaved forest of Pinus massoniana and Castanea mollissima were selected to study the relationships among microbial qualities, community characters and nutrients in soils. The results show that there are highest quantities of bacteria, actinomycetes and fungi in soils of P. pubescen forest and are followed by needle leaved forest and coniferous forest, and the quantities are varied in 32.3 (bacteria), 19.2 (Actinomyces) and 19.3（Fungi）times among the forest colonies. Therefore, the higher the forest productivities and the litter return, the more the soil microbes. Compared to the coniferous forest and needle leaved forest, indexes of diversities, homogeneousness and dominance for microbial colonies are highest in P. pubescen forest soils, which suggests the stable and fine environment in P. pubescen forest soils with rich microbe groups and dominant species or strains. Moreover, microbes are changed seasonally in soils with the highest in summer and the lowest in winter, which are similar to the seasonable variations of available nitrogen and phosphorus in soils. There are positively correlations between microbes and soil organic matter (r=0.592**0.741**, n=24) and NaOH hydrolyzed nitrogen (r=0.490*0.581***, n=24) in all forest soils, and between microbes and available phosphorus in P. pubescen forest soils (r=0.461*, n=24) and needle leaved forest soils (r=0.450*, n=24). Microbes could thus be important in the mineralization of organic matter and in supplies of available nitrogen and phosphorous in forest soils, which influence greatly the productivities of plant communities in forests.