Dynamics of soil respiration in a karst region

Hypotheses: (1) As the drought severity increases, the Rs in karst regions will significantly decrease, and the unique site conditions in these regions (such as shallow soil layers and high permeability) will result in Rs levels that are generally significantly lower than those in non-karst regions. (2) Under karst hydrological drought conditions, the Rs will increase significantly as the amount of rainfall increases, and the response intensity of the Birch effect after rainfall will also exhibit a positive correlation with the amount of rainfall.