Effectiveness of mixed cultivated grasslands to reduce sediment concentration in runoff on hillslopes in the Qinghai-Tibetan Plateau

Abstract

[Abstract]: The Qinghai-Tibetan Plateau has unique geographical and climatic conditions that predetermine soil erosion. In-situ monitoring of soil erosion at high altitudes is extremely difficult and challenging due to harsh environmental conditions. This study examines the in-situ effects of different mixed cultivated grassland on runoff and sediment yield through runoff plots. The results showed that the cultivated grasslands could increase 41.5%-175.9% runoff and reduce 51.2%-58.8% sediment concentration compared to bare land. The combination of rhizomatic type (Poa pratensis L.cv. Qinghai) and dense-plexus type (Deschampsia cespitosa) cultivated grasslands appears an effective approach to prevent soil erosion on extremely degraded grassland. The aboveground characteristics and root system of plants determined rainwater movement in the soil and shifted the runoff and sediment in cultivated grassland community. Our findings indicate that plant morphological characteristics should be considered when alleviating soil erosion in the early stage of cultivated grassland in alpine areas. These results provide a new insight into vegetation restoration and soil and water conservation in alpine areas.