Drought effects on nitrogen and phosphorus releases from litter vary between arid and humid areas: A meta-analysis

Climate warming has intensified the global hydrological cycle, amplifying the differences in precipitation and soil moisture between arid and humid areas. Such a change under regional drought may alter nitrogen (N) and phosphorus (P) releases during litter decomposition in terrestrial ecosystems, but how these biogeochemical processes respond to drought differently between arid and humid areas remains unclear. Here, we compiled 259 and 138 paired observations (with and without drought conditions) to assess the global variations in the drought effects on N and P releases during litter decomposition between arid (aridity index < 0.5) and humid (aridity index > 0.5) areas. Litter N release increased under drought in both arid (0.35%) and humid (3.62%) areas, and P release decreased by 7.32% in arid areas but increased by 2.22% in humid areas under drought. These changes in N and P releases from decomposing litter were positively correlated with drought duration in arid areas, dependent on microclimate, edaphic factors, and litter quality. Our findings highlight the contrasting effects of drought on litter N and P releases between arid and humid ecosystems, and this differential influence will greatly improve our capability to evaluate and forecast nutrient cycling during litter decomposition under different precipitation patterns.