Aridity and NPP constrain contribution of microbial necromass to soil organic carbon in the Qinghai-Tibet alpine grasslands

Microbial necromass carbon (MNC) is key to soil organic carbon (SOC) storage. However, mechanisms regulating MNC accumulation on large scales are poorly understood. Here we provide the first batch of regional-scale MNC data based on amino sugars for the Qinghai-Tibet Plateau alpine grasslands. We show that Qinghai-Tibet grasslands have similar microbial biomass carbon (MBC) but lower MNC concentrations in SOC than Mongolian and other grasslands. The low contribution of MNC to SOC is mainly attributed to high aridity and low net primary productivity of the Qinghai-Tibet grasslands. Our findings highlight climatic and plant influences on MNC accumulation at regional scales.

Automated summary

This study provides regional-scale data on MNC accumulation in alpine grasslands of the Qinghai-Tibet Plateau, showing that the grasslands have low MNC concentrations in SOC due to high aridity and low net primary productivity. The findings highlight the influences of climate and plant factors on MNC accumulation at regional scales.