PNNL

Abstract

Soil organic matter (SOM) is a reservoir for global carbon (C) that maintains soil fertility and prevents the release of greenhouse gases. Microbial necromass, consisting of dead cells and cellular components, is considered a major contributor to SOM formation. Yet, methods for enhancing the accumulation of mineral-associated microbial necromass in soil are still unknown. Here, we used 13C to trace microbial necromass persistence in a year-long laboratory incubation of soils from two agricultural research sites differing in texture and mineralogy. Isotopic tracing revealed that for both silty and sandy loams, approximately 89% of the microbial necromass was recovered in the fine (