Abstract: [Objective] To assess the effects of various nutrient treatments on population characteristics and grass yields of Stipa grandis grassland. [Method] In Tumuji Town, Jalaid Banner, Hinggan League, Inner Mongolia, the impacts of organic fertilizer application, chemical fertilizer application, grazing, and control （without management methods） on grassland population characteristics and grass yields were analyzed with random block design in the year of 2021. Single component analysis and multiple comparison were used to examine the variations in grassland population characteristics and grass yields across the four treatments. [Result] Grassland population characteristics and grass yields were affected differently by various treatments. Compared with the control, the treatments of organic fertilizer, chemical fertilizer, and grazing all raised the importance value of Achnatherum sibiricum, with chemical fertilizer treatment increased significantly （P<0.05）, while the importance value of Stipa grandis and Arundinella hirta dropped. Organic fertilizer treatment enhanced grass height in comparison to the control, whereas the treatments of chemical fertilizer and grazing lowered grass height. Chemical fertilizer treatment increased grass coverage significantly （P<0.05） compared to the control, but the treatments of organic fertilizer and grazing reduced grass coverage. The treatments of organic fertilizer and chemical fertilizer increased grass yields compared to the control, with chemical fertilizer treatment increased extremely significantly （P<0.01）, but grazing treatment decreased fresh grass yields. [Conclusion] Organic fertilizer treatment improved the importance value , grass height, and grass yields of Achnatherum sibiricum, and chemical fertilizer treatment improved the importance value , grass coverage, and grass yields of Achnatherum sibiricum.

Key words: nutrient management, Stipa grandis grassland, population characteristics, productivity