Effects of the vegetation restoration years on soil microbial community composition and biomass in degraded lands in Changting County, China

We evaluated the effects of the number of years of restoration of vegetation on soil microbial community structure and biomass in degraded ecosystems. We investigated the microbial community structure by analyzing their phospholipid fatty acids then examined microbial biomass carbon and nitrogen by chloroform fumigation extraction of restoration soils over several years. The data were compared with those of highly degraded lands and native vegetation sites. The results show that the duration of vegetation on the sites substantially increased microbial biomass and shifted the microbial community structure even after only 4 years. However, microbial communities and biomass did not recover to the status of native vegetation even after 35 years of vegetation cover. A redundancy analysis and Pearson correlation analysis indicated that soil organic carbon, total nitrogen, available potassium, soil water content, silt content and soil hardness explained 98.4% of total variability in the microbial community composition. Soil organic carbon, total nitrogen, available potassium and soil water content were positively correlated with microbial community structure and biomass, whereas, soil hardness and silt content were negatively related to microbial community structure and biomass. This study provides new insights into microbial community structure and biomass that influence organic carbon, nitrogen, phosphorus and potassium accumulation, and clay content in soils at different stages of restoration.