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Imprint of management on microbial communities in arable soil

implications for N2O emissions

Putz, Martina (2018). Imprint of management on microbial communities in arable soil. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2018:35
ISBN 978-91-7760-210-1
eISBN 978-91-7760-211-8
[Doctoral thesis]

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Abstract

Arable soils are a major source of the greenhouse gas nitrous oxide (N2O), emissions of which are directly linked to increased use of N fertilizers. Microbial communities that drive N cycle processes in soil ultimately determine the fate of reactive N inputs and control N2O emissions. Under anoxic conditions, two processes compete for nitrate (NO3-): denitrification, the stepwise reduction of NO3- to N2O or atmospheric nitrogen, and dissimilatory nitrate reduction to ammonium (DNRA), in which NO3- is reduced to ammonium (NH4+). The reduction of N2O by denitrifiers and non-denitrifying N2O reducers is the only known biological sink for N2O.
The aim of this thesis was to investigate how edaphic factors that are altered by soil management practices influence the diversity, structure and activity of the soil microbiota regulating anaerobic N cycling, and thereby N2O emissions. We hypothesised that N replete conditions and long-term fertilization promote incomplete denitrifiers, whereas high C content increases the abundance of DNRA bacteria and N2O reducing organisms, enhancing soil N2O sink capacity. Inoculation of soil microcosms with a non-denitrifying N2O reducing strain confirmed that increased abundance of these organisms can mitigate soil N2O emissions. A survey of long-term fertilization trials showed a consistent increase in the relative abundance of taxonomic groups previously inferred from genomic evidence to produce or consume N2O in fertilized soil. Nevertheless, the abundance of organisms comprising a truncated denitrification remained dominant, concomitant with increased potential N2O emissions. Another field study including fertilization and different crop rotations suggested that changes in soil C/N ratio due to cropping system influenced the competition between DNRA and denitrification, with higher C/N promoting DNRA and N2O reducing community abundance and activity. This was confirmed in controlled manipulations of C/N in a microcosm study, suggesting that soils covering higher C/N ratios sustain a greater abundance of DNRA and N2O reducing bacteria and therefore have a lower N2O emission potential.

Authors/Creators:Putz, Martina
Title:Imprint of management on microbial communities in arable soil
Subtitle:implications for N2O emissions
Alternative abstract:
LanguageAbstract
Swedish

Jordbruksmark är den enskilt största källan av växthusgasen lustgas, vilket är direkt kopplat till det ökade användandet av kvävegödsel. Mikrobsamhällen i marken avgör vad som händer med tillsatt kväve och styr lustgasproduktionen. Under syrefria förhållanden påverkas nitrat i marken av två processer: denitrifikation, som stegvis omvandlar nitrat till lustgas eller till atmosfäriskt kväve, och dissimilatorisk nitratreduktion till ammonium (DNRA), som omvandlar det till ammonium. Denitrifierande bakterier, och icke - denitrifierande lustgasreducerande bakterier, är den enda kända biologiska lustgassänkan.
Syftet med denna avhandling var att undersöka hur brukandet av jorden påverkar mångfalden, strukturen och aktiviteten hos de marklevande mikroorganismer som reglerar de dominerande anaeroba kväveomvandlingsprocesserna i mark, och därigenom lustgasproduktionen. Hypotesen var att kväverika förhållanden och långvarig gödsling gynnar icke fullständiga denitrifierare, medan kolrika förhållanden ökar mängden DNRA-bakterier och lustgasreducerande organismer, vilket stärker jordens lustgassänkande kapacitet. Vi inokulerade jord med icke denitrifierande lustgasreducerande bakterier, vilket bekräftar ett samband mellan antalet lustgasrducerande bakterier och minskad lustgasproduktionen. I en studie med långliggande gödslingförsök fann vi att kvävegödsling konsekvent ökade förekomsten av organismer med genetiska förutsättningar för att både producera och konsumera lustgas. Trots detta dominerades jordarna av ofullständigt denitrifierande organismer, vilket leder till ökad potential för lustgasproduktion. En annan fältstudie med gödsling i växtföljder med och utan vall indikerade att växtföljden orsakar förändringar i jordens kol-kväve-förhållande, vilket påverkar balansen mellan DNRA och denitrifikation: högre kol-kväve-kvot ger mer DNRA och ett mikrobsamhälle med bättre förmåga att reducera lustgas. Detta bekräftades i kontrollerade försök där kol-kväve-förhållandet i olika jordar manipulerades.

Series/Journal:Acta Universitatis Agriculturae Sueciae (1652-6880)
Year of publishing :18 May 2018
Depositing date:18 May 2018
Volume:2018:35
Number of Pages:64
Papers/manuscripts:
NumberReferences
IDomeignoz-Horta L.A., Putz M., Spor A., Bru D., Breuil M.C., Hallin S. Philippot L. (2016). Non-denitrifying nitrous oxide-reducing bacteria – An effective N2O sink in soil. Soil Biology and Biochemistry, 103, 376-379
IIPutz M., Jones C.M., Emmerich M., Hallin S. Fertilizer-induced N2O production is consistently linked to changes in soil microbial community composition and community functions controlling N2O. (manuscript)
IIIPutz M., Schleusner P., Rütting T., Hallin S. Relative abundance of denitrifying and DNRA bacteria and their activity determine nitrogen retention or loss in agricultural soil (Soil Biology and Biochemistry, accepted)
IVPutz M., Maheshwari A., Jones C.M., Hallin S. Legacy effects of N fertilization and soil C:N ratio controls microbial communities and N2O emissions under anoxic conditions. (manuscript)
Place of Publication:Uppsala
Publisher:Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-7760-210-1
ISBN for electronic version:978-91-7760-211-8
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P34 Soil biology
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Environmental Sciences (social aspects to be 507)
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Microbiology (Microbiology in the medical area to be 30109)
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Environmental Sciences related to Agriculture and Land-use
Agrovoc terms:denitrification, arable soils, nitrous oxide, microbial flora, fertilization
Keywords:denitrification, arable soil, nitrous oxide, microbial communities, DNRA, fertilization, C:N ratio
URN:NBN:urn:nbn:se:slu:epsilon-e-4886
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-4886
ID Code:15471
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Forest Mycology and Plant Pathology
(S) > Dept. of Forest Mycology and Plant Pathology
Deposited By: Martina Putz
Deposited On:18 May 2018 07:08
Metadata Last Modified:06 Sep 2018 11:33

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