Conclusion
This research evaluated nutrient limitation of soil microbial communities during land use change from the perspective of microbial metabolisms around the Danjiangkou Reservori area of central China. Conversion of uncultivated land to woodland, shrubland plantations or cropland in this region stimulated soil N cycling via increased N-hydrolyzing enzyme activities and specific enzyme activities. High C and N contents were the major controls on higher N-hydrolyzing enzyme activities under afforestation and cultivation. Soil temperature was an important factor in regulating the seasonal variations in enzyme activities. Although microbial nutrient metabolisms were co-limited by N and P, especially P across all land use types, N and P limitation were decreased with cultivation and afforestation. The nutrient limitation of microbial metabolisms strongly depended on the contents and stoichiometries of the soil nutrients. Overall, these findings suggested that the coupling of soil enzyme stoichiometry and nutrient status to reveal soil microbial metabolic limitation and nutrient cycling under global land use change.