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.