Microbial biomass and nutrients in soil at the different stages of secondary forest succession in Ziwulin, northwest China.

摘要

Microbial biomass, organic carbon (Corg), total nitrogen (TN), and microbial quotient (MBC/Corg) in soil were determined during the secondary forest succession in north Ziwulin region in the middle of Loess Plateau, Gansu, China. Results showed that with secondary forest succession, Corg, TN, microbial biomass carbon (MBC) and N (MBN) in soil increased quickly, and tended to be the highest contents under the 17-year secondary forest (SF17), after that they decreased and gradually remained at quite a constant level, suggesting that accumulations of Corg, TN, MBC and MBN in soil occurred mainly at the early succession stages (before SF17). Soil microbial biomass was markedly correlated with the Corg and TN content of soil (P<0.01), Furthermore, microbial quotient showed significant correlation not only with MBC and Corg, but also with succession duration during the secondary forest succession. Therefore, the results suggested that changes in microbial biomass in soil were relative not only to the quantity, but also to the quality of soil organic matter during secondary forest succession, and that changes in aboveground plant species during succession were critical to improve the degradation of the soil physical, chemical and microbial properties in north Ziwulin of Loess Plateau, China..