Responses of growing‐season soil respiration to water and nitrogen addition as affected by grazing intensity

1. Most grasslands in the world, including the semi-arid steppe in China, are threatened by nitrogen deposition, precipitation change, and livestock grazing, which greatly affect soil carbon processes (e. g., soil respiration). Although the individual effects of nitrogen deposition and precipitation change on soil respiration are well understood, how their effects on soil respiration are altered by different grazing intensities is unclear. 2. To determine how the effects of nitrogen deposition and precipitation change on soil respiration are affected by grazing intensity, we conducted an experiment in a semi-arid steppe involving areas that experienced 10 years of no, light, moderate, or heavy grazing. These areas were treated with water addition (110 mm, 30% of the mean annual precipitation) and nitrogen addition (10.5 g m-2 yr-1). 3. Our results showed that relative to no grazing, grazing decreased growing-season soil respiration by 10-19%. The decline in soil respiration was mainly v...