Effects of artificial grassland establishment on soil nutrients and carbon properties in a black-soil-type degraded grassland

Disturbance and management approaches can contribute significantly to restoration of degraded grassland ecosystems. This study has examined the re-establishment of artificial grassland to renew extremely degraded black-soils in an alpine area of the Qinghai-Tibetan Plateau, in China. We evaluated this method for which grassland ecosystem responses to this restoration approach are needed. Here, we evaluated the response of aboveground plant communities and belowground soil nutrient and soil carbon storage to the establishment of artificial grassland in grasslands on black-soils in the eastern Qinghai-Tibetan Plateau. Three grasslands sites were selected: a degraded grassland on an original black-soil, and 3- and 6-year-old Elymus nutans artificial grasslands. Artificial grassland establishment significantly improved aboveground biomass, but also significantly decreased species richness, diversity and evenness for black-soil-type degraded grassland. Artificial grassland establishment resulted in significantly improved soil total nitrogen and phosphorus, and decreased soil organic matter, available nitrogen, and phosphorus, especially in the depth of 20–30 cm soil layer. Although artificial grassland establishment significantly improved soil organic carbon in the topsoil (0–10 cm), it decreased at depths of 10–20 and 20–30 cm. Six-year artificial grassland significantly increased soil carbon storage compared with black-soil-type degraded grasslands. Accordingly, artificial grassland can be used as effective restoration and rehabilitation approach to improve productivity and regulate community and soil properties in black-soil-type degraded grasslands. Our results suggest that ecosystem functions such as production of aboveground biomass, the provision of soil surface cover, and nutrient accumulation may be provided by artificial grassland. However, more time is needed for plant diversity and soil carbon storage functions to recover fully from degradation.