Soil enzyme activity and stoichiometry in response to precipitation changes in terrestrial ecosystems

Soil extracellular enzymes play a key role in catalyzing organic matter decomposition, and enzymatic stoichiometry is a critical metric for reflecting shifts in soil microbial functions. Changes in precipitation can influence belowground ecosystem processes by regulating soil microbial functions under global change. However, the effects of increased (+PRE) and decreased precipitation (–PRE) on soil enzyme activity and stoichiometry remain poorly understood. In this study, we performed a global meta-analysis using 167 observations from 61 field studies to investigate the effects of precipitation changes on soil enzyme activity and stoichiometry. The results showed that + PRE increased the N- and P-acquiring enzyme activities by an average of 26% and 13%, respectively. +PRE led to a decrease in the enzymatic C:N ratio in the forests and dry areas. The –PRE had no general effect on soil C- and N-acquiring enzymes or their ratios. Soil N-acquiring enzyme activity, enzymatic C:N and N:P ratios were sensitive to slight + PRE, suggesting that moderate precipitation is conducive to enzyme production by microbial communities. Soil enzyme activity and stoichiometry were predominantly influenced by the experimental duration of precipitation changes, and their response to precipitation were closely associated with root biomass and the fungi-to-bacteria ratio. Collectively, precipitation changes may have a general impact on N-acquiring enzyme activity with consequences for the stoichiometry of soil resource recycling under global changes.