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Trace gas, Growth yield, Nitrate, Soil, Simulation, Fluxes, Evolution, Water, Pseudomonas-denitrificans, N20 production

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Subject-Keyword: Trace gas Growth yield Nitrate Soil Simulation Fluxes Evolution Water Pseudomonas-denitrificans N20 production

Type of item: Journal Article Published

Language: English



Description: Confidence in regional estimates of N2O emissions used in national greenhouse gas inventories could be improved by using mathematical models of the biological and physical processes by which these emissions are known to be controlled. However these models must first be rigorously tested against field measurements of N2O fluxes under well documented site conditions. Spring thaw is an active period of N2O emission in northern ecosystems and thus presents conditions well suited to model testing. The mathematical model ecosys, in which the biological and physical processes that control N2O emissions are explicitly represented, was tested against N2O and CO2 fluxes measured continuously during winter and spring thaw using gradient and eddy covariance techniques. In the model, ice formation at the soil surface constrained soil-atmosphere gas exchange during the winter, causing low soil O-2 concentrations and consequent accumulation of denitrification products in the soil profile. The removal of this constraint to gas exchange during spring thaw caused episodic emissions of N2O and CO2, the timing and intensities of which were similar to those measured in the field. Temporal variation in these emissions, both simulated and measured, was high, with those of N2O ranging from near zero to as much as 0.8 mg N m-2 h-1 within a few hours. Such variation should be accounted for in ecosystem models used for temporal integration of N2O fluxes when making long-term estimates of N2O emissions.

Date created: 1999

DOI: doi:10.7939-R3JQ0SX34

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Rights: © 1999 American Geophysical Union. This version of this article is open access and can be downloaded and shared. The original authors and source must be cited.

Autor: Grant, R.F. Pattey, E.



13, NO 2, PAGES 679-694, JUNE 1999 Mathematical modeling of nitrous oxide emissionsfrom an agricultural field during spring thaw R.F.
Grant Departmentof RenewableResources,Universityof Alberta,Edmonton,Alberta,Canada E.
Pattey EasternCereal and OilseedsResearchCentre, Ottawa, Ontario, Canada Abstract.
Confidencein regionalestimates of N20 emissions usedin nationalgreenhouse gas inventoriescouldbe improvedby usingmathematicalmodelsof the biologicalandphysical processes by whichtheseemissionsareknownto be controlled.Howeverthesemodelsmustfirst be rigorouslytestedagainstfield measurements of N20 fluxesunderwell documented site conditions.Springthaw is an activeperiodof N20 emissionin northernecosystems andthus presentsconditionswell suitedto modeltesting.The mathematical modelecosys,in whichthe biologicalandphysicalprocesses that controlN20 emissions areexplicitlyrepresented, wastested againstN20 andCO2fluxesmeasuredcontinuously duringwinterandspringthaw usinggradient andeddycovariancetechniques.In the model,ice formationat the soil surfaceconstrained soilatmosphere gasexchangeduringthe winter,causinglow soil02 concentrations andconsequent accumulationof denitrificationproductsin the soilprofile.The removalof this constraintto gas exchangeduringspringthaw causedepisodicemissions of N20 andCO2,the timing and intensitiesof whichwere similarto thosemeasuredin the field.
Temporalvariationin these emissions,both simulatedandmeasured,was high,with thoseof N20 rangingfrom nearzero to as muchas0.8 mgN m-2h-•withina fewhours.Suchvariationshouldbeaccounted for in ecosystem modelsusedfor temporalintegrationof N20 fluxeswhenmakinglong-termestimatesof N20 emissions. 1.
Introduction Techniquesfor estimatingemissionsof N20 from soils are needed to evaluate managementoptions for reducing such emissionsas part of the Canadian commitmentto reduce the greenhousegases released to the atmosphere.However N20 emissionsare controlledby several intera...

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