Short-term study of subalpine forest soils reveals that microbial communities are strongly influenced by the litter and organic layers

Abstract

Given the wide range of factors influencing soil microbial communities, the aim of our study was to investigate how these communities respond to changes in plant inputs, litter, and removal of soil organic layers, in a subalpine forest. Our study site was located on the slopes of Yulong Snow Mountain, Yunnan, China. We analyzed the effect of litter, tree roots, and the organic horizon on soil microbial communities, using phospholipid fatty acid (PLFA) analysis and by monitoring any changes in soil properties, over two months. Our results showed that the gram-positive bacteria and gram-negative bacteria ratio (G+/G-), after the second month of all treatments, was significantly higher than after the first month of treatment. The biomass of the soil microbial community is sensitive to response to variation of the soil environment. Removal of the organic horizon and additional litter coverage significantly decreased the biomass of fungi, fungi/bacteria and total PLFA, and significantly increased the G+/G- ratio compared with the control and other treatments after two months. Organic horizon and litter layer removal significantly increased the G+/G- ratio. Litter removal significantly increased the biomass of arbuscular mycorrhizal fungi. Contrary to our expectations, root removal had no effect on the biomass of the soil microbial communities during two months' treatment.