This study was conducted in a Stipa breviflora desert steppe in central-western Inner Mongolia. Based on a long-term （since 2004） fixed-site grazing control experiment platform， four gradients of grazing intensities were set up： ungrazed （Control check， CK）， lightly grazing （LG）， moderately grazing （MG）， and heavy grazing （HG）. Litter and soil samples （0-30 cm depth） were collected to systematically analyze the contents and stoichiometric ratio characteristics of carbon （C）， nitrogen （N）， and phosphorus （P）. The results showed that with increasing grazing intensity， the litter standing crop and its C， N， and P contents decreased significantly， reflecting a reduction in both the quantity and quality of litter. In contrast， the contents of C， N， and P in the soil did not change significantly as grazing intensity increased. However， under moderately and heavy grazing intensities， the coupling relationships among soil nutrients weakened， which indicated that overgrazing led to the “decoupling” of the plant-litter-soil system. This study demonstrates that litter is not only a direct target of grazing impacts but also a key link in the system’s nutrient cycling and feedback regulation. Long-term high-intensity grazing may weaken this regulatory role and exacerbate nutrient limitations. These findings provide important scientific insights for the in-depth understanding of nutrient cycling mechanisms in desert steppe ecosystems and the guidance of ecological restoration and management practices.

Desert steppe  /  Grazing intensity  /  Plant-litter-soil system  /  Ecological stoichiometry