Grass clippings mulch enhances soil hydrological function during alpine cultivated grasslands reclamation

The reclamation of severely degraded alpine meadows faces a critical challenge: the loss of the organic-rich mattic epipedon has led to ecohydrological dysfunction, manifesting as high evapotranspiration and reduced soil water storage. This dysfunction severely limits restoration outcomes, thereby threatening the vital roles these meadows play in water conservation and ecosystem stability. Here, a three-year field experiment examined the contribution of grass clippings mulch in enhancing soil hydrological function during alpine cultivated grasslands reclamation in an extremely degraded alpine meadow, under these treatments: extremely degraded alpine meadow (EDM, as Control), artificial cultivated grassland reclamation without mulching (AGR), and artificial cultivated grassland reclamation with mulching by grass clippings (AGRM, using 200·g m -2 of grass debris as surface mulch). Results showed that grass clipping mulch during cultivated grassland reclamation (AGRM) significantly enhanced revegetation, increasing plant cover, density, and aboveground biomass by 34.82%, 71.17%, and 54.87% relative to no mulch plots (AGR). Crucially, grass clipping mulch during cultivated grassland reclamation (AGRM) significantly reduced soil temperature and evapotranspiration by 18.71% and 25.00% compared to non-restored controls (EDM). This reclamation approach also elevated belowground biomass by 31.94%, which subsequently significantly increased soil water storage potential by 35.33% through improvements in soil total porosity (+5.57%) and saturated moisture capacity (+10.64%). This study demonstrates that integrating grass clipping mulch into cultivated grassland reclamation can effectively enhance the ecohydrological function of degraded alpine meadows, thus providing both practical and theoretical implications for overcoming soil hydrological constraints in high-altitude restoration.