Analysis of the soil microbial communities in Pinus tabulaeformis Carr. and Bupleurum chinense plantations of the Xiaolongshan Mountain region, Gansu Province, China

Abstract

Soil microbes play important roles in the nutrient cycles and energy flows of the soil ecosystem. Bupleurum chinense has long been widely cultivated on piedmont farmland in the Xiaolongshan Mountain region; however, the piedmont farmland that was formerly planted with Bupleurumchinense has now been planted with seedlings of Pinus tabulaeformis, a species that has recently been promoted widely in the region. Changes in the composition of the soil microbial community after planting with P. tabulaeformis are not well understood. In this study, using high-throughput sequencing technology, we investigate the soil microbial community of four year old P. tabulaeformis and B.chinense plantations in the Xiaolongshan Mountain region. Furthermore, the response of the soil microbial community to the changes in soil properties was analysed. The soil organic matter (SOM) and available phosphorus (AP) contents were lower in P. tabulaeformis plantations compared with B.chinense plantations. The soil fungal community in P.tabulaeformis plantations had higher diversity indices than that in B.chinense plantations. With respect to the dominant bacterial groups, Proteobacteria had lower relative abundance in P. tabulaeformis soil than in B.chinense soil, and Chloroflexi had higher relative abundance in P. tabulaeformis soil than in B.chinense soil. For the dominant fungal groups, Ascomycota was less abundant in P. tabulaeformis soil than in B.chinense soil. Redundancy analysis (RDA) showed that the SOM significantly correlated with soil fungal communities. These findings suggest that soil nutrients of the cultivated land were decreased in plantations of P. tabulaeformis 4 years after planting. Pinustabulaeformis did not significantly affect soil bacterial communities; however, the changes in the soil fungal communities of both Pinustabulaeformis and Bupleurumchinense plantations may be attributed to the phyla present (Ascomycota), which were primarily affected by soil organic matter in the Xiaolongshan Mountain region.