Abstract

In order to assess the dynamics of microbial-diversity through vegetation successions, sample sites for soil investigation at the 10a, 25a, 40a, 75a natural secondary Pinus tabulaeformis Carr. forests were established in the forest region of Loess Plateau, China. With the succession extension, soil microbial biomass carbon (MBC), moisture content, soil organic carbon (SOC) as well as total N also exhibited an increase before decreasing trend with succession gradient. Soil indexes of the soil shannon diversity index (H), which incorporates both richness and evenness of all soil microbial-species observed in the plots according to T-RFs peaks composition determined by terminal restriction fragment length polymorphism (T-RFLP), also exhibited a similar trend with soil physicochemical properties during the succession. In the late-succession of 75a, its soil fertility and microbial-community structure is distant from other three stages, suggesting that it may be a specific stage to the recession succession. The result of a dendrogram of hierarchical cluster of the microbial-community structure of four succession stages showed that 75a was distant to the other three sample sites, and 25a and 40a represented the most similar microbial-community structure of all stages. It was concluded that the underground succession of natural secondary P. tabulaeformis Carr. forests in the forest region of Loess Plateau, China, is significantly linked to its aboveground. We infer that natural secondary succession of P. tabulaeformis Carr forest will be replaced by the Qercu sliaotungensis in the coming centuries in the forest region of Loess Plateau, China.  

Key words: Soil microbial-community; natural secondary succession, T-RFLP, Loess Plateau.