loading page

Root-derived inputs are major contributors to soil carbon in temperate forests
  • +2
  • Adrienne Keller,
  • Edward Brzostek,
  • Matthew Craig,
  • Joshua Fisher,
  • Richard Phillips
Adrienne Keller
Indiana University Bloomington
Author Profile
Edward Brzostek
West Virginia University
Author Profile
Matthew Craig
Oak Ridge National Laboratory
Author Profile
Joshua Fisher
California Institute of Technology
Author Profile
Richard Phillips
Indiana University
Author Profile

Peer review status:UNDER REVIEW

14 May 2020Submitted to Ecology Letters
18 May 2020Assigned to Editor
18 May 2020Submission Checks Completed
20 May 2020Reviewer(s) Assigned

Abstract

Roots promote the formation of slow-cycling soil carbon (C), yet we have limited understanding of the magnitude and controls on this flux. We hypothesized that root-derived inputs from ectomycorrhizal (ECM)-associated trees would be greater than those from arbuscular mycorrhizal (AM)-associated trees, and that soils receiving the greatest inputs would promote greater root-derived C accumulation in mineral-associated pools. We installed δ13C-enriched ingrowth cores across mycorrhizal gradients in six Eastern U.S. forests (n = 54 plots). Counter to our hypothesis, root-derived C was 54% greater in AM versus ECM-dominated plots, resulting in 175% more root-derived C in mineral-associated, slow-cycling pools in AM compared to ECM plots. Notably, root-derived soil C was comparable in magnitude to leaf litter inputs and aboveground net primary production. Our results suggest that variation in root-derived C inputs due to tree mycorrhizal dominance may be a key control of soil C dynamics in forests.