Effects of Drought on Dissolved Organic Carbon Content in Grassland and Forest Soils

Drought has been proved to be an important climatic factor affecting carbon (C) and nitrogen (N) cycles in terrestrial ecosystems. Despite this general understanding, relatively few studies have been conducted on the effects of drought on dissolved organic carbon (DOC) in soil in different ecosystems. To investigate whether the effects of drought on soil DOC varied in different ecosystems, and whether the difference increased with drought intensity (DI) and drought duration (DD), we conducted a meta-analysis synthesizing responses of DOC to droughts (or precipitation reduction experiments) in two main natural ecosystems: forests and grasslands. The data was gathered from 43 recent publications (457 samples of data at 34 sites) about the drought experiments across the globe. On average, drought reduced the DOC content of forest soils by 9.24%, and this effect escalated with increase in DI and mean annual temperature (MAT). In contrast, the DOC content of grassland soils was not significantly affected by drought. Overall, the effects of drought on soil DOC depend on ecosystem type (ET), mean annual precipitation (MAP), MAT and DI, and their interactions.