Sustained microbial reorganization after 30 years of variations in litter deposition underpins the persistence of soil organic matter molecular classes
Persistent URL
Author(s)
Wrightson, Isla
Bowden, Richard D.
Allegheny College
Wang, Junjian
Lajtha, Kate
Simpson, Myrna J.
Date Issued
July 7, 2026
Abstract
Forest soils store vast amounts of carbon (C), but the stability in part depends on the quality and quantity of above- and belowground C litter inputs, which are impacted by management decisions and global environmental change. We assessed soil organic matter (SOM) composition in forest floor and upper mineral soil (0–10 cm) after three decades of altering litter sources in a temperate deciduous forest at the Bousson Experimental Forest in Pennsylvania where treatments included leaf and/or root exclusion or doubled litter inputs. Elemental analysis, targeted compound analysis, solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy, radiocarbon analyses, and measurements of microbial biomass and community composition were employed to characterize soil. Within the top 10 cm of mineral soil, C concentrations did not increase under the Double Litter treatment after 30 years of added litter. Instead elevated microbial biomass (+29%) supported by the availability of fresh substrates, indicated by radiocarbon signatures, suggest that microbes sustained decomposition of SOM and limited C accumulation in the upper mineral soil. The exclusion treatments (No Litter, No Roots, and No Inputs) also exhibited lower C concentrations in the upper mineral soil, with NMR analyses revealing advanced stages of SOM decomposition. Microbial community composition also shifted under exclusion treatments, with radiocarbon data suggesting greater reliance on older C pools when fresh inputs were limited. This indicates a microbial response to reduced preferred substrates, whereby community reorganization supports metabolic maintenance. Comparisons between 20 and 30 years of treatment demonstrate that microbial and biogeochemical responses have continued to shift over time with altered litter and root inputs. Together, our results underscore the dynamic interplay between microbial communities and SOM persistence under changing environmental conditions.
Journal
Environmental Science: Advances
Citation
Isla Wrightson, Richard D. Bowden, Junjian Wang, Kate Lajtha, Myrna J. Simpson; Sustained microbial reorganization after 30 years of variations in litter deposition underpins the persistence of soil organic matter molecular classes. Environ. Sci.: Adv. 2026; https://doi.org/10.1039/d5va00350d
Publisher
Royal Society of Chemistry (RSC)
DOI
10.1039/d5va00350d
ISSN
2754-7000
Rights
© 2026 The Author(s). Published by the Royal Society of Chemistry This article is licensed under a Creative Commons Attribution-Non Commercial 4.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.
Type of Publication
Journal Article
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