The restoration and improvement of the degraded natural grassland ecosystem in the Qilian mountains rely heavily on the strong support of composite measures. This study aims to enhance grassland productivity and forage quality in the Qilian mountains, providing technical references for ecological restoration.

Compound measures for grassland improvement, including grass seed combination reseeding, reseeding with grass seed mixtures + compound fertilizer + pest control, were adopted to investigate their effects on species diversity, grassland productivity, and forage nutritional value in the grassland ecosystem.

1) After adopting composite measures, the species composition of the temperate grassland plant community in the northern foothills of the Qilian mountains significantly improved compared to the control grassland; the average vegetation height and grass yield also significantly increased by 20.9% and 56.8%, respectively. 2) After adopting the combined measures of “Poa pratensis + Elymus nutans + Dongnong 1 alfalfa” plus “Agropyron cristatum” or “Bromus inermis”, the Shannon-Wiener diversity index of the community significantly increased compared to the control. The combined measures of “Poa pratensis + Elymus nutans” plus “Dongnong 1 alfalfa + Agropyron cristatum” or “Elymus sibiricus + Bromus inermis” followed by the application of nitrogen, phosphorus, potassium compound fertilizer and nicotine-matrine insect control measures significantly increased the Pielou evenness index and Margalef richness index. The Simpson ecological dominance index and Simpson diversity index of the community in the experimental area showed no significant difference compared to the control; 3) After adopting the combined measures of “Poa pratensis + Elymus nutans” plus “Dongnong 1 alfalfa + Elymus sibiricus” or “Dongnong 1 alfalfa + Agropyron cristatum” or “Agropyron cristatum + Ganyin 1 rye”, the crude protein content of the grassland forage significantly increased compared to the control, by 30.2%, 19.8% and 32.7%, respectively. After adopting the combined measures of “Poa pratensis + Elymus nutans + Dongnong 1 alfalfa” plus “Ganyin 1 rye” or “Elymus sibiricus” or “Agropyron cristatum” followed by the application of nitrogen, phosphorus, potassium compound fertilizer and nicotine-matrine insect control measures, the crude protein content of the grassland forage significantly increased compared to the control, by 19.8%, 47.7% and 18.0%, respectively.

The combination of “Kentucky bluegrass + Elymus nutans + Dongnong No.1 alfalfa + Agropyron cristatum” and the application of nitrogen, phosphorus, and potassium compound fertilizer and nicotine-matrine insect control measures performed optimally, significantly enhancing grassland productivity and improving grassland quality, greatly increasing grassland carrying capacity, and providing a scientific basis for the restoration and management of the Qilian mountain grassland ecosystem.