Land rehabilitation improves edaphic conditions and increases soil microbial biomass and abundance

Abstract

Rehabilitation of farmland improves the local eco-environmental conditions. But to what extent this transformation influences soil microbial properties is less known. In our study we compared variations in soil microbial attributes following changes in land-use types to understand the influence of altered soil properties on microbial biomass and their community structure using chloroform fumigation extraction method and phospholipid fatty acid (PLFA) analysis. For this purpose, 3 agricultural (AL) (farmland, apple orchard and 2 years abandoned land) and 4 rehabilitated lands (RL) of various vegetations grassland, shrubland, mixed forest (Amorpha fruticosa and Pinus tabuliformis Carr.) and forest (Robinia pseudoacacia) were selected. Our results showed higher soil organic carbon (SOC) contents in RL soils (forest >mixed forest >grassland>shrub land) than that in AL soils. In RL soils, soil microbial biomass and abundance of group specific PLFA were significantly higher than those in AL soils. Under different land-use types, microbial community was bacteria dominated over fungi. The microbial physiological indices (G+/G–, cyc/prec and S/M) indicated decreased environmental stress in RL soils in comparison with AL soils. In loess soils, SOC and total N correlated positively (p < 0.05) with microbial biomass C, N and P and also with fungal and bacterial PLFA, indicating a positive microbial mediation in improving soil fertility. Taking together, our findings suggest that land rehabilitation, especially Robinia pseudoacacia planation, improves overall edaphic conditions and accelerates soil microbial biomass accumulation in local regions.