Influence of different slope position and profile in Disporopsis pernyi forest land on soil microbial biomass and enzyme activity in southwest Karst mountain of China

Soil microbial biomass and enzyme activity are important parameters to evaluate the quality of the soil environment. The goal of this study was to determine the influence of different slope position and section in Disporopsis pernyi forest land on the soil microbial biomass and enzyme activity in southwest Karst Mountain. In this study,we chose the Dip forest land at Yunfo village Chengdong town Liangping country Chongqing Province as the study object,to analyze the influence of three different slope positions [Up Slope( US),Middle Slope( MS),Below Slope( BS) ] and two different sections-upper layer( 0-15 cm) and bottom layer( 15-30 cm) on the soil microbial biomass carbon( SMBC),soil microbial biomass nitrogen( SMBN),microbial carbon entropy( qMBC),microbial nitrogen entropy( qMBN),catalase( CAT),alkaline phosphatase( ALK),urease( URE),and invertase( INV). The results showed that the same trend( BS MS US) was found for SMBC,SMBN,qMBC,qMBN,CAT and INV of upper soil layer,while a different trend( BS US MS) was observed for ALK. In addition,another trend( MS US BS) was observed for URE. The same trend( BS MS US) was observed for SMBN,qMBN,CAT,ALK,URE and INV in bottom layer,but a different trend( MS BS US) was observed for SMBC and qMBC. The SMBC,SMBN,CAT,ALK,URE and INV manifested as upper bottom with reduction of the section,while qMBC and qMBN showed the opposite trend. Correlation analysis indicated that there were significant( P 0. 05) or highly significant( P 0. 01) positive correlations among SMBC in different slope position and section,soil enzyme activity and moisture. According to the two equations of regression analysis,SMBC tended to increase with the increasing CAT and ALK,while decreased with the increasing pH. Then SMBN tended to increase with the increasing URE and INV.