Studies on the impacts of grazing on carbon, nitrogen, and phosphorus stoichiometry and storage are crucial for better understanding the nutrient cycles of grasslands ecosystems. Using a controlled grazing experimental platform in a meadow steppe ecosystem, the effects of different stocking rates (0.00, 0.23, 0.34, 0.46, 0.69, and 0.92 AU ha⁻¹) on the carbon, nitrogen, and phosphorus contents of plant functional groups were explored. The major results were: (1) The carbon content of Gramineae Barnhart was significantly reduced by grazing intensity (p < 0.05), and the organic carbon content of Cyperaceae Rotundus was significantly higher than that of the other groups; the total nitrogen content of Cyperaceae and other groups and total phosphorus contents of Gramineae, Leguminosae Sp., Cyperaceae, and other groups all increased significantly with increasing grazing intensity (p < 0.05). (2) The carbon, nitrogen, and phosphorus storage amounts of Gramineae, Leguminosae, and Ranunculaceae L. decreased significantly with increasing grazing intensity. Heavy grazing reduced the carbon, nitrogen, and phosphorus storage amounts of Cyperaceae and other groups, while the carbon, nitrogen, and phosphorus storage amounts of Compositae were the largest under moderate grazing. (3) The nitrogen content of each functional group was highly significantly negatively correlated with the C/N ratio, and the phosphorus content was highly significantly negatively correlated with the C/P ratio. Grazing and foraging affected the growth of the different functional groups, which in turn affected their carbon, nitrogen, and phosphorus content, stoichiometry, and storage. Moderate grazing improved the nutrient utilization efficiency of grassland and is beneficial for promoting sustainable grassland development.

Studies on the impacts of fertilization on plant production and species diversity are crucial for better maintaining the stability of grassland ecosystems and restoring degraded grasslands. Using a controlled fertilization experimental platform in a temperate Leymus chinensis meadow steppe ecosystem, the effects of different levels of nitrogen (N) and phosphorus (P) addition on plant community structure, biomass allocation, diversity, and the correlation relationship were explored. The major results were as follows: (1) The structural composition of the plant community changed after different levels of N and P addition; the dominance ratio and biomass of Poaceae plants increased gradually with increasing N and P addition levels. (2) The addition of N and P increased the height, density and coverage of the plant community, the biomass of the dominant L. chinensis and plant community and the total productivity of grassland, and reduced the root–shoot ratio of grassland biomass. For example, plant community biomass, gramineous plant biomass and grassland total productivity increased by 84.46–204.08%, 162.64–424.20%, and 38.12–46.44%, respectively, after N and P addition. (3) The community richness, diversity, and evenness indices decreased overall and showed binomial regression after N and P addition; the functional group of Poaceae plants was highly significantly negatively correlated with species diversity indices and was highly significantly positively correlated with the aboveground biomass of L. chinensis and community; Leguminosae plants and Ranunculaceae plants were highly significantly positively correlated with Margalef and Patrick richness indices; Ranunculaceae plants were highly significantly and negatively correlated with L. chinensis biomass, community biomass, and Poaceae plants. Moderate fertilization not only improved the plant community structure and productivity but was also beneficial for maintaining the grassland species diversity and stability.

Long-term grazing leads to soil degradation in Inner Mongolia grassland. Based on the Hulunbeier meadow steppe, the variation characteristics of soil nitrogen content and storage in soil layers between 0–40 cm, under six different grazing intensities, and the response of vegetation and other physical and chemical properties of soil to grazing were studied. The main results were as follows: (1) Moderate grazing increased soil total nitrogen (TN), soluble total nitrogen (STN) and microbial biomass nitrogen (MBN) contents, while heavy grazing decreased MBN content. In the year with more rain, heavy grazing increased nitrate nitrogen (NO₃⁻-N) content and storage, while less rain increased ammonium nitrogen (NH₄⁺-N) content. (2) The proportion of 0–40 cm nitrogen components showed an upward trend in the year with more rain, and the opposite in the years with less rainfall with the increase of grazing intensity. Soil soluble organic nitrogen (SON) and NO₃⁻-N storages decreased and MBN storage increased in rainy years. (3) Soil nitrogen component contents and storages were correlated with plant growth status, soil moisture (SM) and soil bulk density (SBD), and were significantly negatively correlated with soil temperature (ST) and pH (p < 0.05). The content and storage of soil nitrogen were affected by grazing, soil, vegetation, meteorological and other environmental factors. Moderate grazing was more conducive to the improvement of soil nitrogen storage capacity and the healthy development of grassland.