Differential effects of warming and nitrogen fertilization on soil respiration and microbial dynamics in switchgrass croplands

Jianwei Li; Siyang Jian; Jason P. de Koff; Chad S. Lane; Gangsheng Wang; Melanie A. Mayes; Dafeng Hui

doi:10.1111/gcbb.12515

Differential effects of warming and nitrogen fertilization on soil respiration and microbial dynamics in switchgrass croplands

Jianwei Li
, Siyang Jian
, Jason P. de Koff
, Chad S. Lane
, Gangsheng Wang
, Melanie A. Mayes
, Dafeng Hui

Ecosystem Processes

Research output: Contribution to journal › Article › peer-review

27 Scopus citations

Abstract

The mechanistic understanding of warming and nitrogen (N) fertilization, alone or in combination, on microbially mediated decomposition is limited. In this study, soil samples were collected from previously harvested switchgrass (Panicum virgatum L.) plots that had been treated with high N fertilizer (HN: 67 kg N ha⁻¹) and those that had received no N fertilizer (NN) over a 3-year period. The samples were incubated for 180 days at 15 °C and 20 °C, during which heterotrophic respiration, δ¹³C of CO₂, microbial biomass (MB), specific soil respiration rate (R_s: respiration per unit of microbial biomass), and exoenzyme activities were quantified at 10 different collections time. Employing switchgrass tissues (referred to as litter) with naturally abundant ¹³C allowed us to partition CO₂ respiration derived from soil and amended litter. Cumulative soil respiration increased significantly by 16.4% and 4.2% under warming and N fertilization, respectively. Respiration derived from soil was elevated significantly with warming, while oxidase, the agent for recalcitrant soil substrate decomposition, was not significantly affected by warming. Warming, however, significantly enhanced MB and R_s indicating a decrease in microbial growth efficiency (MGE). On the contrary, respiration derived from amended litter was elevated with N fertilization, which was consistent with the significantly elevated hydrolase. N fertilization, however, had little effect on MB and R_s, suggesting little change in microbial physiology. Temperature and N fertilization showed minimal interactive effects likely due to little differences in soil N availability between NN and HN samples, which is partly attributable to switchgrass biomass N accumulation (equivalent to ~53% of fertilizer N). Overall, the differential individual effects of warming and N fertilization may be driven by physiological adaptation and stimulated exoenzyme kinetics, respectively. The study shed insights on distinct microbial acquisition of different substrates under global temperature increase and N enrichment.

Original language	English
Pages (from-to)	565-576
Number of pages	12
Journal	GCB Bioenergy
Volume	10
Issue number	8
DOIs	https://doi.org/10.1111/gcbb.12515
State	Published - Aug 2018

Funding

J Li and S Jian contributed equally to this work. This study was supported by funding from a US Department of Agriculture Evans-Allen grant awarded to JL (No. 1005761) and US Department of Energy (DOE) Office of Biological and Environmental Research through the Terrestrial Ecosystem Science Scientific Focus Area (TES-SFA) at Oak Ridge National Laboratory (ORNL). ORNL is managed by the University of Tennessee– Battelle, LLC, under contract no. DE-AC05-00OR22725 with the US DOE. We thank Richard Link for site establishment and maintenance, and Sherly Celada, Tariq Muhammad, and Dr. Chunlan Guo for their laboratory assistance. We appreciate the anonymous reviewers for their constructive comments and suggestions. J Li and S Jian contributed equally to this work. This study was supported by funding from a US Department of Agriculture Evans-Allen grant awarded to JL (No. 1005761) and US Department of Energy (DOE) Office of Biological and Environmental Research through the Terrestrial Ecosystem Science Scientific Focus Area (TES-SFA) at Oak Ridge National Laboratory (ORNL). ORNL is managed by the University of Tennessee?Battelle, LLC, under contract no. DE-AC05-00OR22725 with the US DOE. We thank Richard Link for site establishment and maintenance, and Sherly Celada, Tariq Muhammad, and Dr. Chunlan Guo for their laboratory assistance. We appreciate the anonymous reviewers for their constructive comments and suggestions. Notice: This manuscript has been authored by UT-Battelle, LLC, under contract no. DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).

Keywords

exoenzyme activities
heterotrophic respiration
microbial biomass
microbial growth efficiency
nitrogen fertilization
soil warming
switchgrass

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10.1111/gcbb.12515

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@article{904846db0796446d8ffee08198460dc4,

title = "Differential effects of warming and nitrogen fertilization on soil respiration and microbial dynamics in switchgrass croplands",

abstract = "The mechanistic understanding of warming and nitrogen (N) fertilization, alone or in combination, on microbially mediated decomposition is limited. In this study, soil samples were collected from previously harvested switchgrass (Panicum virgatum L.) plots that had been treated with high N fertilizer (HN: 67 kg N ha−1) and those that had received no N fertilizer (NN) over a 3-year period. The samples were incubated for 180 days at 15 °C and 20 °C, during which heterotrophic respiration, δ13C of CO2, microbial biomass (MB), specific soil respiration rate (Rs: respiration per unit of microbial biomass), and exoenzyme activities were quantified at 10 different collections time. Employing switchgrass tissues (referred to as litter) with naturally abundant 13C allowed us to partition CO2 respiration derived from soil and amended litter. Cumulative soil respiration increased significantly by 16.4\% and 4.2\% under warming and N fertilization, respectively. Respiration derived from soil was elevated significantly with warming, while oxidase, the agent for recalcitrant soil substrate decomposition, was not significantly affected by warming. Warming, however, significantly enhanced MB and Rs indicating a decrease in microbial growth efficiency (MGE). On the contrary, respiration derived from amended litter was elevated with N fertilization, which was consistent with the significantly elevated hydrolase. N fertilization, however, had little effect on MB and Rs, suggesting little change in microbial physiology. Temperature and N fertilization showed minimal interactive effects likely due to little differences in soil N availability between NN and HN samples, which is partly attributable to switchgrass biomass N accumulation (equivalent to \textasciitilde{}53\% of fertilizer N). Overall, the differential individual effects of warming and N fertilization may be driven by physiological adaptation and stimulated exoenzyme kinetics, respectively. The study shed insights on distinct microbial acquisition of different substrates under global temperature increase and N enrichment.",

keywords = "exoenzyme activities, heterotrophic respiration, microbial biomass, microbial growth efficiency, nitrogen fertilization, soil warming, switchgrass",

author = "Jianwei Li and Siyang Jian and \{de Koff\}, \{Jason P.\} and Lane, \{Chad S.\} and Gangsheng Wang and Mayes, \{Melanie A.\} and Dafeng Hui",

note = "Publisher Copyright: {\textcopyright} 2018 The Authors. GCB Bioenergy Published by John Wiley \& Sons Ltd",

year = "2018",

month = aug,

doi = "10.1111/gcbb.12515",

language = "English",

volume = "10",

pages = "565--576",

journal = "GCB Bioenergy",

issn = "1757-1693",

publisher = "Wiley Open Access",

number = "8",

}

TY - JOUR

T1 - Differential effects of warming and nitrogen fertilization on soil respiration and microbial dynamics in switchgrass croplands

AU - Li, Jianwei

AU - Jian, Siyang

AU - de Koff, Jason P.

AU - Lane, Chad S.

AU - Wang, Gangsheng

AU - Mayes, Melanie A.

AU - Hui, Dafeng

PY - 2018/8

Y1 - 2018/8

N2 - The mechanistic understanding of warming and nitrogen (N) fertilization, alone or in combination, on microbially mediated decomposition is limited. In this study, soil samples were collected from previously harvested switchgrass (Panicum virgatum L.) plots that had been treated with high N fertilizer (HN: 67 kg N ha−1) and those that had received no N fertilizer (NN) over a 3-year period. The samples were incubated for 180 days at 15 °C and 20 °C, during which heterotrophic respiration, δ13C of CO2, microbial biomass (MB), specific soil respiration rate (Rs: respiration per unit of microbial biomass), and exoenzyme activities were quantified at 10 different collections time. Employing switchgrass tissues (referred to as litter) with naturally abundant 13C allowed us to partition CO2 respiration derived from soil and amended litter. Cumulative soil respiration increased significantly by 16.4% and 4.2% under warming and N fertilization, respectively. Respiration derived from soil was elevated significantly with warming, while oxidase, the agent for recalcitrant soil substrate decomposition, was not significantly affected by warming. Warming, however, significantly enhanced MB and Rs indicating a decrease in microbial growth efficiency (MGE). On the contrary, respiration derived from amended litter was elevated with N fertilization, which was consistent with the significantly elevated hydrolase. N fertilization, however, had little effect on MB and Rs, suggesting little change in microbial physiology. Temperature and N fertilization showed minimal interactive effects likely due to little differences in soil N availability between NN and HN samples, which is partly attributable to switchgrass biomass N accumulation (equivalent to ~53% of fertilizer N). Overall, the differential individual effects of warming and N fertilization may be driven by physiological adaptation and stimulated exoenzyme kinetics, respectively. The study shed insights on distinct microbial acquisition of different substrates under global temperature increase and N enrichment.

AB - The mechanistic understanding of warming and nitrogen (N) fertilization, alone or in combination, on microbially mediated decomposition is limited. In this study, soil samples were collected from previously harvested switchgrass (Panicum virgatum L.) plots that had been treated with high N fertilizer (HN: 67 kg N ha−1) and those that had received no N fertilizer (NN) over a 3-year period. The samples were incubated for 180 days at 15 °C and 20 °C, during which heterotrophic respiration, δ13C of CO2, microbial biomass (MB), specific soil respiration rate (Rs: respiration per unit of microbial biomass), and exoenzyme activities were quantified at 10 different collections time. Employing switchgrass tissues (referred to as litter) with naturally abundant 13C allowed us to partition CO2 respiration derived from soil and amended litter. Cumulative soil respiration increased significantly by 16.4% and 4.2% under warming and N fertilization, respectively. Respiration derived from soil was elevated significantly with warming, while oxidase, the agent for recalcitrant soil substrate decomposition, was not significantly affected by warming. Warming, however, significantly enhanced MB and Rs indicating a decrease in microbial growth efficiency (MGE). On the contrary, respiration derived from amended litter was elevated with N fertilization, which was consistent with the significantly elevated hydrolase. N fertilization, however, had little effect on MB and Rs, suggesting little change in microbial physiology. Temperature and N fertilization showed minimal interactive effects likely due to little differences in soil N availability between NN and HN samples, which is partly attributable to switchgrass biomass N accumulation (equivalent to ~53% of fertilizer N). Overall, the differential individual effects of warming and N fertilization may be driven by physiological adaptation and stimulated exoenzyme kinetics, respectively. The study shed insights on distinct microbial acquisition of different substrates under global temperature increase and N enrichment.

KW - exoenzyme activities

KW - heterotrophic respiration

KW - microbial biomass

KW - microbial growth efficiency

KW - nitrogen fertilization

KW - soil warming

KW - switchgrass

UR - https://www.scopus.com/pages/publications/85045831785

U2 - 10.1111/gcbb.12515

DO - 10.1111/gcbb.12515

M3 - Article

AN - SCOPUS:85045831785

SN - 1757-1693

VL - 10

SP - 565

EP - 576

JO - GCB Bioenergy

JF - GCB Bioenergy

IS - 8

ER -

Differential effects of warming and nitrogen fertilization on soil respiration and microbial dynamics in switchgrass croplands

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Keywords

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