Carbon and oxygen controls on N2O and N2 production during nitrate reduction

Morley, Nicholas; Baggs, Elizabeth M.

doi:10.1016/j.soilbio.2010.07.008

Cited by 211 publications

(136 citation statements)

References 48 publications

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“…Second, the availability of O 2 in soil is an important control of denitrification (Morley and Baggs, 2010) and is strongly correlated to soil water content (Smith, 1990). In the tomato experiment, the WFPS declined faster in the M treatment during the gas measurements, probably due to enhanced plant transpiration induced by the higher plant biomass, or by enhanced water removal directly induced by AMF (RuizLozano and Azcon, 1995;Auge, 2001;Khalvati et al, 2005).…”

Section: Discussionmentioning

confidence: 98%

Symbiotic relationships between soil fungi and plants reduce N2O emissions from soil

et al. 2013

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N 2 O is a potent greenhouse gas involved in the destruction of the protective ozone layer in the stratosphere and contributing to global warming. The ecological processes regulating its emissions from soil are still poorly understood. Here, we show that the presence of arbuscular mycorrhizal fungi (AMF), a dominant group of soil fungi, which form symbiotic associations with the majority of land plants and which influence a range of important ecosystem functions, can induce a reduction in N 2 O emissions from soil. To test for a functional relationship between AMF and N 2 O emissions, we manipulated the abundance of AMF in two independent greenhouse experiments using two different approaches (sterilized and re-inoculated soil and non-mycorrhizal tomato mutants) and two different soils. N 2 O emissions were increased by 42 and 33% in microcosms with reduced AMF abundance compared to microcosms with a well-established AMF community, suggesting that AMF regulate N 2 O emissions. This could partly be explained by increased N immobilization into microbial or plant biomass, reduced concentrations of mineral soil N as a substrate for N 2 O emission and altered water relations. Moreover, the abundance of key genes responsible for N 2 O production (nirK) was negatively and for N 2 O consumption (nosZ) positively correlated to AMF abundance, indicating that the regulation of N 2 O emissions is transmitted by AMF-induced changes in the soil microbial community. Our results suggest that the disruption of the AMF symbiosis through intensification of agricultural practices may further contribute to increased N 2 O emissions.

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Section: Discussionmentioning

confidence: 98%

Symbiotic relationships between soil fungi and plants reduce N2O emissions from soil

et al. 2013

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“…Controls on N 2 O flux are also highly complex (Groffman et al, 2009), with N 2 O originating from as many as four separate sources (e.g., bacterial ammonia oxidation, archaeal ammonia oxidation, denitrification, dissimilatory nitrate reduction to ammonium), each with different environmental controls (Baggs, 2008;Morley and Baggs, 2010;Firestone and Davidson, 1989;Firestone et al, 1980;Pett-Ridge et al, 2013;Silver et al, 2001;Prosser and Nicol, 2008). Key factors regulating soil N 2 O flux include redox, soil moisture content or water table depth, temperature, pH, labile C availability, and labile N availability (Groffman et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Key factors regulating soil N 2 O flux include redox, soil moisture content or water table depth, temperature, pH, labile C availability, and labile N availability (Groffman et al, 2009). As is the case for CH 4 , variations in redox/water table depth play an especially prominent role in regulating N 2 O flux in tropical peatland ecosystems because all of the processes that produce N 2 O are redox-sensitive, with bacterial or archaeal ammonia oxidation occurring under aerobic conditions (Prosser and Nicol, 2008;Firestone and Davidson, 1989;Firestone et al, 1980) whereas nitrate-reducing processes (i.e., denitrification, dissimilatory nitrate reduction to ammonium) occur under anaerobic ones (Firestone and Davidson, 1989;Firestone et al, 1980;Morley and Baggs, 2010;Silver et al, 2001). Moreover, for nitrate-reducing processes, which are believed to be the dominant source of N 2 O in wet systems, the extent of anaerobiosis also controls the relative proportion of N 2 O or N 2 produced during dissimilatory metabolism (Firestone and Davidson, 1989;Firestone et al, 1980;Morley and Baggs, 2010;Silver et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Seasonal variability in methane and nitrous oxide fluxes from tropical peatlands in the western Amazon basin

et al. 2017

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Abstract. The Amazon plays a critical role in global atmospheric budgets of methane (CH 4 ) and nitrous oxide (N 2 O). However, while we have a relatively good understanding of the continental-scale flux of these greenhouse gases (GHGs), one of the key gaps in knowledge is the specific contribution of peatland ecosystems to the regional budgets of these GHGs. Here we report CH 4 and N 2 O fluxes from lowland tropical peatlands in the Pastaza-Marañón foreland basin (PMFB) in Peru, one of the largest peatland complexes in the Amazon basin. The goal of this research was to quantify the range and magnitude of CH 4 and N 2 O fluxes from this region, assess seasonal trends in trace gas exchange, and determine the role of different environmental variables in driving GHG flux. Trace gas fluxes were determined from the most numerically dominant peatland vegetation types in the region: forested vegetation, forested (short pole) vegetation, Mauritia flexuosadominated palm swamp, and mixed palm swamp. Data were collected in both wet and dry seasons over the course of four field campaigns from 2012 to 2014. Diffusive CH 4 emissions averaged 36.05 ± 3.09 mg CH 4 -C m −2 day −1 across the entire dataset, with diffusive CH 4 flux varying significantly among vegetation types and between seasons. Net ebullition of CH 4 averaged 973.3 ± 161.4 mg CH 4 -C m −2 day −1 and did not vary significantly among vegetation types or between seasons. Diffusive CH 4 flux was greatest for mixed palm swamp (52.0 ± 16.0 mg CH 4 -C m −2 day −1 ), followed by M. flexuosa palm swamp (36.7 ± 3.9 mg CH 4 -C m −2 day −1 ), forested (short pole) vegetation (31.6 ± 6.6 mg CH 4 -C m −2 day −1 ), and forested vegetation (29.8 ± 10.0 mg CH 4 -C m −2 day −1 ). Diffusive CH 4 flux also showed marked seasonality, with divergent seasonal patterns among ecosystems. Forested vegetation and mixed palm swamp showed significantly higher dry season (47.2 ± 5.4 mg CH 4 -C m −2 day −1 and 85.5 ± 26.4 mg CH 4 -C m −2 day −1 , respectively) compared to wet season emissions (6.8 ± 1.0 mg CH 4 -C m −2 day −1 and 5.2 ± 2.7 mg CH 4 -C m −2 day −1 , respectively). In contrast, forested (short pole) vegetation and M. flexuosa palm swamp showed the opposite trend, with dry season flux of 9.6 ± 2.6 and 25.5 ± 2.9 mg CH 4 -C m −2 day −1 , respectively, versus wet season flux of 103.4 ± 13.6 and 53.4 ± 9.8 mg CH 4 -C m −2 day −1 , respectively. These divergent seasonal trends may be linked to very high water tables (> 1 m) in forested vegetation and mixed palm swamp during the wet season, which may have constrained CH 4 transport across the soil-atmosphere interface. Diffusive N 2 O flux was very low (0.70 ± 0.34 µg N 2 O-N m −2 day −1 ) and did not vary significantly among ecosystems or between seasons. We conclude that peatlands in the PMFB are large and regionally significant sources of atmospheric CH 4 that need to be better accounted for in regional emissions inventories. In contrast, N 2 O flux was negligible, suggesting that this region does not make a significant contribut...

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“…The observed increase in soil pH may, however, have either 334 directly decreased the proportion of N2O: N2 emitted from soil, or enabled the biochar to act as an 335 'electron shuttle' increasing the transfer of electrons to denitrifying bacteria (Cayuela et al, 2013). On 336 addition, the incorporation of biochar into the soil introduces fresh labile C which may have increased 337 the conversion of N2O to N2, by increasing the availability of C electron acceptors for denitrifying 338 organisms (Azam et al, 2002;Morley and Baggs, 2010;Saggar et al, 2013;Senbayram et al, 2012). 339…”

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confidence: 99%

Biochar suppresses N2O emissions while maintaining N availability in a sandy loam soil

Case

McNamara

Reay

et al. 2015

Soil Biology and Biochemistry

182

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Our results show that biochar suppressed cumulative soil N2O production by 91 % in near-saturated, 23 fertilised soils. Cumulative denitrification was reduced by 37 %, which accounted for 85 -95 % of 24 soil N2O emissions. We also found that physical/chemical and biological ammonium (NH4 + ) 25 immobilisation increased with biochar amendment but that nitrate (NO3 -) immobilisation decreased. 26We concluded that this immobilisation was insignificant compared to total soil inorganic N content. In 27 contrast, soil N mineralisation significantly increased by 269 % and nitrification by 34 % in biochar-28 amended soil. 29These findings demonstrate that biochar amendment did not limit inorganic N availability to nitrifiers 30 and denitrifiers, therefore limitations in soil NH4 + and NO3 -supply cannot explain the suppression of 31 N2O emissions. These results support the concept that biochar application to soil could significantly 32 mitigate agricultural N2O emissions through altering N transformations, and underpin efforts to 33 develop climate-friendly agricultural management techniques. 34 2

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Carbon and oxygen controls on N2O and N2 production during nitrate reduction

Cited by 211 publications

References 48 publications

Symbiotic relationships between soil fungi and plants reduce N2O emissions from soil

Symbiotic relationships between soil fungi and plants reduce N2O emissions from soil

Seasonal variability in methane and nitrous oxide fluxes from tropical peatlands in the western Amazon basin

Biochar suppresses N2O emissions while maintaining N availability in a sandy loam soil

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