5 Conclusion
We found that GE had caused significant soil acidification across China’s grasslands. Surface soil pH showed greatest decline rates in GE grasslands, while deeper soil pH showed limited responses to GE. In general, the largest decrease in soil pH occurred after medium-term periods (5–15 years) of GE, whereas soil pH exhibited a smaller response in long-term periods (≥15 years) of GE. Of the environmental factors examined, MAP, biomass accumulation and soil C and N dynamics were the important factors influencing the RPC following GE. Grassland dominated by sedge species had a higher pH decrease rate in surface soil, whereas forbs and shrubs had the lowest RPC in deeper soil. Our results provide an important reference for future grassland management in China.