Ecology-Oriented Assessment of Temporal Stumping Effects on Soil Respiration in the Kubuqi Desert

Given the significant regulatory effect of stumping on carbon exchange processes in the vegetation–soil system, this study conducted a one-year continuous observation of soil respiration in Salix psammophila stands starting six months after stumping, aiming to reveal the changes in soil respiration characteristics and their main driving factors before and after stumping. In 2023, a stumping experiment was established in Dalate Banner, Ordos, and soil respiration in stumped Salix psammophila plantations was continuously monitored from 2023 to 2024. The relationships between soil respiration, soil temperature, and soil moisture were analyzed using fitting models, and the effects of stumping on soil physicochemical properties were further assessed. Results showed that soil respiration exhibited a unimodal diurnal pattern, reaching the annual minimum in winter (December 2023) and the maximum in midsummer (August 2024). Stumping significantly reduced soil respiration rates across diurnal, seasonal, and annual scales. This reduction was attributed both to direct effects, through decreased vegetation carbon input and altered root distribution, and to indirect effects, via changes in soil temperature and moisture. Model fitting indicated that the dual-factor model incorporating soil temperature and moisture explained variations in soil respiration more effectively than single-factor models, with the bivariate nonlinear model providing the best fit. In addition, stumping improved the vertical distribution of soil nutrients by enhancing the accumulation of organic matter and organic carbon in the middle soil layer and increasing total nitrogen content in the surface soil. Soil pH showed only slight variations across treatments and depths, remaining consistently within the strongly alkaline range (9.37–9.56).