); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China; [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (M.D. )1 School of Resource and Environmental Sciences, Wuhan University, Wuhan 4300079, China; [EMAIL_ADDRESS] (Z.Z. vegetation productivity exhibits significantly higher sensitivity to drought stress compared to humid zones. These fluctuations are not only dominated by climatic factors but also involve nonlinear interactions with human activities [7; 8]. In China's semi-arid zones, NPP shows significant positive correlations with annual precipitation, CO\({}_{2}\) emissions, and GDP [9]. Studies on the Mongolian Plateau further confirm that climate warming and human activities jointly drive NPP growth, with human activities contributing more than 30%, highlighting the vulnerability and complexity of the ecosystems in semi-arid zones [10]. While drought's inhibitory effect on NPP is well established, its mechanisms remain controversial. Studies in the Amazon forest demonstrate that short-term droughts reduce NPP through photosynthetic inhibition caused by decreased stomatal conductance [11]. The decrease in relative water content of the leaf will gradually reduce the stomatal conductivity and slow down the CO\({}_{2}\) assimilation [12]. In contrast, research in China's Qinling-Daba Mountains reveals that drought-induced NPP suppression varies significantly with drought duration, indicating temporal-scale dependency [13]. Analyses in the Yellow River Basin further demonstrated that drought and extreme temperature events significantly suppress NPP, which exhibits strong correlations with precipitation and temperature, while sensitivity to drought varies substantially across vegetation types [14; 15]. However, the existing studies are mostly limited to unidimensional analysis of precipitation shortage and fail to systematically integrate the synergistic effects of multiple elements such as evapotranspiration anomalies and soil water storage deficit [16; 17]. Moreover, NPP responses to drought are influenced not only by drought intensity but also depend on vegetation types and ecosystem structural configurations [18]. Drought has a significant negative effect on NPP of grassland, and different types of grassland are sensitive to drought [19]. Grassland ecosystems exhibit higher drought sensitivity owing to shallower root systems, whereas forests demonstrate greater resilience through deeper root penetration and canopy interception capacity [20]. However, current research predominantly focuses on single vegetation types or short-term observations, lacking comprehensive basin-scale comparisons across ecosystems. Moreover, systematic quantification of drought's cumulative impacts and legacy effects remains critically understudied [21]. While afforestation remains a cornerstone strategy for strengthening terrestrial carbon sequestration globally, its ecological impacts in semi-arid regions remain contentious.