Based on a long-term grazing experiment platform established in the Stipa breviflora desert steppe， this study analyzed the dynamic changes in the nutritional quality of two dominant plants Stipa breviflora and Cleistogenes songorica under different grazing intensities and duration. The results indicated that both moderate and heavy grazing significantly reduced the crude protein （CP） content of the both species. Heavy grazing significantly increased the neutral detergent fiber （NDF） content in the both species and significantly reduced the ether extract （EE） content of Cleistogenes songorica， while light grazing significantly reduced the crude ash content of Stipa breviflora. As the grazing season progressed， the CP content of the both species gradually decreased， whereas the ether extract and acid detergent fiber （ADF） contents exhibited an initial increase followed by a decrease. Specifically， the ether extract content of Stipa breviflora and Cleistogenes songorica peaked in August and July， respectively， while the ADF content for both species reached its maximum in July. Furthermore， CP significant negatively correlated with NDF， as well as between ether extract with crude ash. In contrast， NDF and ADF showed a significant positive correlation. These findings provide a scientific basis for improving the utilization efficiency of biological resources in the Stipa breviflora desert steppe of Inner Mongolia and contribute to the sustainable management of grassland ecosystems.

Grazing capacity  /  Grazing time  /  Desert grassland  /  Forage nutrition