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  • Long‐term nitrogen fertilization inhibits carbon and nitrogen loss during late‐stage fungal necromass decomposition depending on necromass chemistry
Title: Long‐term nitrogen fertilization inhibits carbon and nitrogen loss during late‐stage fungal necromass decomposition depending on necromass chemistry
Abstract Fungal necromass is increasingly recognized as a key component of soil carbon (C) and nitrogen (N) cycling. However, how C and N loss from fungal necromass during decomposition is impacted by global change factors such as anthropogenic N addition and changes to soil C supply (e.g. via changing root exudation and rhizosphere priming) remains unclear and understudied relative to plant tissues.To address these gaps, we conducted a year‐long decomposition experiment with four species of fungal necromass incubated across four forested sites in plots that had received inorganic N and/or labile C fertilization for two decades in Minnesota, USA.We found that necromass chemistry was the primary driver of C and N loss from fungal necromass as well as the response to fertilization. Specifically, N addition suppressed late‐stage decomposition, but this effect was weaker in melanin‐rich necromass, contrary to the hypothesis based on plant litter dynamics that N addition should suppress the decomposition of more complex organic molecules. Labile C addition had no effect on either the early or late stages of necromass decomposition.Nitrogen release from necromass also varied among species, with N‐poor necromass having lower N release after controlling for differences in mass loss via regression. The relatively minor effects of N fertilization on the proportion of initial necromass N released suggest that N demand by decomposers is the primary control on N loss during fungal necromass decomposition.Synthesis. Together, our results stress the importance of the afterlife effects of fungal chemical composition to forest soil C and N cycles. Further, they demonstrate that C and N release from this critical pool can be reduced by ongoing anthropogenic N addition.  more » « less
Award ID(s):
1831944
PAR ID:
10659483
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
John Wiley & Sons, Ltd
Date Published:
Journal Name:
Journal of Ecology
Volume:
113
Issue:
9
ISSN:
0022-0477
Page Range / eLocation ID:
2401 to 2413
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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