Effect of soil tillage on reseeded high quality forages after controlling Achnatherum inebrians in alpine grassland

In this study, the widely distributed poisonous weed Achnatherum inebrians in a natural degraded grassland of Gansu Province, northwest China (both sides of the road in Dahe Township, Sunan County) was selected as the experiment material. Following a randomized block experimental design, we treated the experimental plots with glyphosate and heavy-duty harrow to compare their controlling effects on A. inebrians. Following this, high quality forages were selected to reseed these plots and growth improving technology were applied under field conditions. The results indicated that the 10% glyphosate treatment was able to control more than 98% of the A. inebrians, and the 150~190 g·667 m-2 of glyphosate treatment was economically appropriate. The controlling effect of heavy harrow on A. inebrians was more than 90%, and the 30 cm depth of heavy harrow was appropriate. The germination rate of reseeding combinations Ⅴ(Elymus nutans 1 kg·667 m-2) + (Festuca rubra 0.5 kg·667 m-2) + (Poa pratensis 0.3 kg·667 m-2) + (Coronilla varia 0.2 kg·667 m-2) and+Ⅵ (E. nutans 1 kg·667 m-2) +(F. rubra 0.5 kg·667 m-2) + (P. pratensis 0.2 kg·667 m-2) + (C. varia 0.3 kg·667 m-2) under shallow tillage sowing, shallow tillage drilling and loosen the soil treatment were 85% and 73%, 91% and 87%, and 87% and 75%, respectively, which indicated combination Ⅴ and Ⅵ strong adaptability. When the reseeding depths were 0 cm and 4~8 cm, the germination rate and survival rate were lower when compared to 1~4 cm depth, indicating this was the most appropriate depth for reseeding. Compared with control treatment, the shallow tillage drilling and loosening the soil treatments for the reseeding combinations Ⅴ and Ⅵ effectively improved the soil nutrient status, and increased the grass height, density, and biomass and are worth applying in ecological restoration of degraded natural grassland.