Severe degradation and artificial restoration diversely drive runoff and sediment processes in alpine meadows

Artificial grassland is considered an effective measure for restoring severely degraded grassland in alpine areas and has been widely applied on the Qinghai-Tibetan Plateau. However, the specific effects of artificial restoration and degradation on slope runoff and sediment yield are still poorly understood. In this study, we investigated the effects of artificial restoration and degradation on the runoff sediment process in three areas: an alpine meadow (AM), a severely degraded alpine meadow (BL), and a degraded alpine meadow that was restored by artificial grassland (AG). Our findings revealed that the runoff in AG was significantly lower than that in both AM and BL, with reductions by 95.59% and 88.40%, respectively. The sediment yield in AG was significantly reduced, with reductions by 21.77% and 90.54% compared to AM and BL, respectively. Nevertheless, the sediment concentration in AG was 27.22 and 3.26 times higher than that in AM and BL, respectively. Our study provides clear evidence that plant and soil properties play a crucial role in driving soil erosion processes in both AG and BL. Specifically, artificial grassland was effective in inhibiting runoff and sediment yield. This inhibition was attributed to the modification of soil conditions and the interception of rainfall, which were facilitated by the recovery of vegetation coverage and the increased input of organic matter. These findings have significant implications for the artificial restoration of degraded alpine meadows and soil erosion prevention efforts on the Qinghai-Tibetan Plateau.