Arbuscular mycorrhizal fungi promote litter decomposition and alleviate nutrient limitations of soil microbes under warming and nitrogen application

Arbuscular mycorrhizal fungi (AMF) are vital for nutrient cycling and aboveground ecosystem stability. To understand soil microbe resource limitations and AMF feedback regulation of the soil microbial biomass and litter stoichiometry under warming and nitrogen (N) application conditions, a 3-year experiment involving AMF suppression by benomyl under warming and N application conditions was conducted in the Songnen meadow, in which soil microbial nutrient limitation was measured by ecoenzymatic stoichiometry. We assessed the soil microbes and stoichiometric variables of Leymus chinensis and Phragmites australis litter under various treatment conditions. Carbon (C) and phosphorus (P) are commonly limited nutrients in soil microbial communities in the Songnen meadow ecosystem. AMF alleviated soil microbe C and P limitations by decreasing the microbial C:P ratio under warming and N application conditions and by accelerating litter decomposition, which occurred independently of warming and N application. AMF play a critical role in balancing nutrient stoichiometry and are key to maintaining microbial metabolism and nutrient cycle homeostasis. AMF can shorten the litter nutrient cycle, which is of great significance for the absorption, utilization and storage of plant nutrients in the Songnen grassland ecosystem.