Land use change, a key component of global changes, largely impacts ecosystem structures, processes and functioning. Forest regeneration or reforestation can sequester carbon (C) in aboveground biomass and in soil organic matter (SOM). Soil microorganisms are the decomposers of litter and SOM in terrestrial ecosystems, which can regulate multiple input and loss pathways of soil C and nitrogen (N).  

Changes in microbial community structure and function are hypothesized to alter ecosystem processes. Thus, evaluating the effects of land use change on the soil microbial community structure is important for better understanding human effects on the global C cycle. 

Supervised by Prof. CHENG Xiaoli, ZHANG Qian from Wuhan Botanical Garden of Chinese Academy of Sciences conducted a study in Danjiangkou Reservoir region in central China to investigate how the soil microbial community and soil microbial biomass react to land use change. 

The study demonstrated that afforested soils averaged higher total phospholipid fatty acids (PLFAs), bacterial PLFAs, fungal PLFAs, gram-positive bacterial PLFAs, gram-negative bacterial PLFAs, Arbuscular mycorrhizal fungi PLFAs and Actinomycete PLFAs than cropland and uncultivated land soils at both soil layers. Most types of PLFAs were significantly higher in top soil layers than deeper soil layers except in uncultivated land soils.  

Redundancy analysis and Pearson correlation analysis showed that there was a significant relationship between the composition of soil microbial community and environment factors (F = 14.1, P = 0.002). The results of Monte Carlo permutation tests (P < 0.05) showed that the variability of the PLFAs was strongly related to soil organic nitrogen (F = 129.49, P = 0.002) and labile nitrogen (F = 9.41, P = 0.006).  

Basal microbial respiration was found higher in the afforested soils compared with cropland and uncultivated land soils. However afforested soils decreased the basal microbial respiration on a per-unit-PLFA basis, suggesting that more carbon can be accumulated in afforested soils.  

Shifts in microbial community structure caused by land use type conversion are very important for studying long-term C accumulation, soil restoration and reducing greenhouse gas in the future climate change scenarios. 

This research was financially supported by the National Natural Science Foundation of China, and the Strategic Priority Research Program B of the Chinese Academy of Sciences.

The study was published in Scientifice Reports entitled “Alterations in soil microbial community composition and biomass following agricultural land use change”.