Precipitation and land use alter soil respiration in an Inner Mongolian grassland

Purpose Grasslands are facing the threat of climate change and intensive land use. Soil respiration (R-s) in grassland ecosystems can be potentially altered by changes in precipitation and land use. We aimed to quantify the impact of changes in precipitation and common land use practices in an Inner Mongolia grassland, i.e., mowing and grazing, on soil respiration. Methods We performed an in situ experiment with altered precipitation (+50%, ambient, and -50%) and land use (control or fencing, mowing, and grazing) to explore their impacts on soil respiration and its autotrophic (R-a) and heterotrophic (R-h) components. Results Altered precipitation had stronger impacts on abiotic and biotic drivers than land use, leading to stronger impacts on R-s and its components. Over the 3-year experiment, R-s, R-a and R-h decreased by 36%, 42% and 33% with reduced precipitation and increased by 29%, 36% and 25% with increased precipitation, respectively. Grazing and mowing caused relatively small decreases in Rs compared to fencing (generally < 10%). However, precipitation and land use interactively impacted abiotic and biotic drivers and thus R-s. The decrease in R-s with reduced precipitation was greater with grazing (38%) and mowing (37%) than with fencing (32%). Conclusions R-s and its components may decrease under the projected decrease in precipitation and may further decrease with grazing and mowing compared to fencing. Therefore, land use should be considered when predicting grassland carbon cycling in response to future precipitation changes.