Screening Suitable Ecological Grasses and the Seeding Rate in the Muli Mining Area

To target the lack of suitable grass species in the ecological restoration process of the Muli mining area, nine ecological grass species of Gramineae, Gentianaceae, Scrophulariaceae, and Ranunculaceae were selected as experimental materials to simulate the external alkaline environment for a seed germination test, which could be used to explore the response of seed germination to the environment. At the same time, Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa , Koeleria cristata , and Elymus tangutorum were used as test materials to carry out a variety of comparison and screening tests of suitable seeding rates. The effects of the seeding rate on plant coverage, biomass, forage nutrients, and soil properties were analyzed by a variety of comparison and seeding rate tests. The results showed the following: (1) The relative germination rate of Koeleria cristata , Elymus tangutorum , Deschampsia cespitosa , and Poa pratensis L. ‘Qinghai’ was more than 70%, and the coverage in the returning green period was more than 60%, which was significantly higher than that of other treatments ( p < 0.05) and can better adapt to the environment of the Muli mining area compared to other grass species. Meanwhile, the adaptability of Pedicularis kansuensis , Gentiana macrophylla , and Aconitum pendulum was weak. (2) It was found that when the seeding rate was 9 g·m −2 , the biomass of Poa pratensis L. ‘Qinghai’, Deschampsia cespitos , and Koeleria cristata was the highest, which was 296.45 g·m −2 , 224.32 g·m −2 , and 236.35 g·m −2 , which was significantly higher than that of other treatments ( p < 0.05); the aboveground biomass was 356.24 g·m −2 when the seeding rate of Elymus tangutorum was 18 g·m −2 , which was significantly higher than that of other treatments ( p < 0.05). The membership function showed that the comprehensive evaluation value was 0.701, 0.576, 0.610, and 0.673 when the seeding rate of Poa pratensis L. ‘Qinghai’, Deschampsia cespitos , and Koeleria cristata was 9 g·m −2 and the seeding rate of Elymus tangutorum was 18 g·m −2 . To sum up, it is recommended that the four ecological grass species of Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa , Koeleria cristata , and Elymus tangutorum can be used as the main grass species for ecological restoration in high-altitude and alpine areas such as the Muli mining area, which is affected by an alpine climate and fragile habitats. The optimum sowing rate of Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa , and Koeleria cristata is 9 g·m −2 , and that of Elymus tangutorum is 18 g·m −2 . This cultivation method can effectively promote plant growth and development, improve the physicochemical properties of soil, and is conducive to improving the stability and sustainability of artificial grassland in alpine mining areas.