ITS: Alterations to grassland soil nutrient supply and plant consumer manipulations jointly influence fungal necromass decay

Fungal necromass significantly contributes to soil organic carbon (SOC), yet its decomposition in grasslands, resilient carbon sinks, remains understudied. This project investigates how nutrient supply and consumer manipulations affect fungal necromass decay and associated microbial communities within the long-term Cedar Creek Natural Enemies experiment. Established in 2008, the NE experiment includes plots with foliar fungicide (Azoxystrobin, Propiconazole), soil drench fungicide (Mefenoxam), and nutrient additions (N, P, K, micronutrients), applied individually and in combination. We deployed mesh bags containing two fungal necromass types (Cladosporium sp. and Hyaloscypha bicolor) in selected control, foliar fungicide, and soil drench (fungicide) plots, with and without nutrient additions. We characterized fungal and bacterial communities on decaying necromass and in surrounding soil via high-throughput sequencing. Our findings reveal that both nutrient fertilization and foliar fungicide application enhanced below-ground plant biomass, influencing necromass decay and decomposer communities. This work underscores the interactive roles of nutrient availability and consumer activity, alongside necromass quality, in regulating fungal necromass decomposition and soil carbon cycling in temperate grasslands.