Revisiting the quantitative contribution of microbial necromass to soil carbon pool: Stoichiometric control by microbes and soil

Quantitative assessments of soil microbial necromass improve our knowledge of soil carbon (C) sequestration, which is vital for addressing climate change and food security. Here, we revisit the quantitative contribution of microbial necromass to soil organic C (SOC) pool by using an optimized strategy that considers the stoichiometric differences of microbes and the full range of the microbial necromass proportion in soil nitrogen (N) pool. We derive a more applicable estimate of the microbial necromass contribution to SOC pool, reporting a narrower average range (24%–60%) compared with those in recent publications. We further find that the potential contribution of microbial necromass to SOC pool is controlled by the stoichiometry (C/N ratio) of microbes and soil. We suggest soil C sequestration strategy by increasing microbial necromass should well be exploited to improve soil N availability and use microbial species associated with high biomass C/N ratio to boost C accrual.