Microbial necromass carbon （MNC） constitutes a significant component of soil organic carbon （SOC） and plays a vital role in maintaining and enhancing carbon sequestration capacity of grassland ecosystems. The temperate grasslands of northern China represent a crucial component of global grassland ecosystems， but systematic understanding of their microbial necromass carbon content and its driving factors remains limited. To address this gap， this study established transects along a natural rainfall gradient from east to west in Inner Mongolia， covering three grassland types： meadow grassland， typical grassland， and desert grassland. Soil amino sugar content was measured using the biomarker method. By integrating climate and soil characteristics， the study systematically analyzed the distribution of soil microbial necromass carbon and its driving factors. Results indicate that the average microbial necromass carbon content in topsoil is 10.65 g·kg^-1， comprising 4.79 g·kg^-1 bacterial necromass carbon and 14.80 g·kg^-1 fungal necromass carbon. Structural equation modeling reveals that microbial necromass carbon is primarily regulated by annual mean temperature， dissolved organic carbon， and pH. These findings deepen our understanding of the distribution patterns and driving mechanisms of microbial necromass carbon in northern China's temperate grasslands， providing scientific support for regional grassland carbon management and enhancing soil carbon sequestration potential.

Temperate grasslands of northern China  /  Microbial necromass carbon  /  Bacterial necromass carbon  /  Fungal necromass carbon  /  Driving factors