The Mongolian Plateau (MP) is one of the largest contiguous global drylands, stretching about 2.75 million km2 from western Mongolia to the eastern part of the Inner Mongolian Autonomous Region in China, and is famous for its extensive grasslands. As an indispensable component of Eurasian steppes, grasslands of the MP play important roles in animal husbandry, biodiversity conservation, carbon sequestration and ecological barriers (Kang et al. 2007). The grasslands are characterized by perennial herbaceous forbs and grasses with great adaptation to the arid and semi-arid climates. Soils of the grasslands in MP are mainly chestnut with neutral to alkaline pH and are distinguished by low availability of mineral nutrients such as nitrogen (N), phosphorus (P) and iron (Fe), while the soil is rich in calcium and potassium (Hou 1982). Plant species in these grasslands have evolved a diverse range of strategies to adapt to the climatic and edaphic environments. The grasslands in MP, particularly in Inner Mongolia, have degraded severely since 1980’s due to global change (e.g., atmospheric N deposition, changes in patterns of precipitation, and global warming) and human activities (e.g., grazing, mowing and reclamation), as evidenced by reduced aboveground biomass and plant biodiversity, soil desertification and salinization (Zhou et al. 2014; Batunacun et al. 2023) investigated the response of two nutrient-acquisition strategies: root traits and leaf nutrient resorption of perennial herbaceous species, and explored their correlations with long-term mowing in a temperate steppe. They found that root traits of tall and short plants had little response to long-term mowing, but mowing exerted opposite effects on leaf nutrient efficiency (NRE) of the two plant groups. They further showed that root absorption capacity was positively correlated with leaf nutrient-resorption efficiency for tall plants in control plots, but mowing eliminated this correlation. These results suggest that long-term mowing can alter the correlations between alternative resource-acquisition strategies in perennial herbaceous species of Inner Mongolian grasslands.

Ning et al. (2023) focused on the interactive effect of mowing and N addition on soil microbial biomass in an Inner Mongolian grassland. They found that mowing increased soil inorganic N concentrations, available copper (Cu2+) concentrations, plant aboveground net primary production (ANPP), species richness, Shannon–Wiener biodiversity and ratio of fungal to bacterial biomass, and mitigated the N enrichment-induced increase in plant-available soil Mn2+ concentrations. They also showed that mowing did not affect the soil microbial biomass C (MBC), and that soil MBC was positively affected by plant species richness, but negatively by ANPP, soil inorganic N, available Cu2+ and Mn2+ concentrations in mown plots. These findings highlight that mowing cannot mitigate the negative effects of N enrichment on soil MBC, and that soil, plant and microbial properties play important roles in the response of soil MBC to mowing in N-enriched soil.

As a traditional grassland management practice in Inner Mongolia, grazing can affect plant communities (Talle et al. 2016) and soil microbial communities of grassland ecosystems (Rong et al. 2022). In this special issue, Wang et al. (2023) evaluated the effects of grazing intensity on soil microbial diversity and community composition in a desert steppe of Inner Mongolia. Their results show that grazing led to changes in soil bacterial and fungal community composition, such that heavy grazing significantly increased the relative abundances of Chloroflexi, Gemmatimonadetes, and Firmicutes bacteria, while light grazing significantly decreased the relative abundance of Actinobacteria. Further analysis revealed that the bacterial community responded to grazing via changes in the biomass of perennial plant species and SOC, whereas the SOC and soil pH altered the fungal community composition. These findings suggest that optimal grazing intensity can facilitate the recovery of primary productivity and ecosystem functions in a desert steppe.

In summary, the 16 papers in this special issue highlight the diverse roles of plant-soil interactions in responses of different types of grasslands in Inner Mongolia to nutrient enrichment, variation in precipitation, mowing and grazing at species, functional group and community levels. Future studies on the plant-soil interaction in grasslands on the Mongolian Plateau at regional scales would contribute to our development of sustainable grassland management in this unique region under scenarios of global change.