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dc.contributor.advisorBedard-Haughn, Angelaen_US
dc.contributor.advisorLynch, Dereken_US
dc.creatorWallace, Brianen_US
dc.date.accessioned2015-07-07T12:00:18Z
dc.date.available2015-07-07T12:00:18Z
dc.date.created2015-04en_US
dc.date.issued2015-07-06en_US
dc.date.submittedApril 2015en_US
dc.identifier.urihttp://hdl.handle.net/10388/ETD-2015-04-2090en_US
dc.description.abstractThe transfer of N from legume green manures (GMr) can satisfy the needs of a successive cash crop, but rotations that have over-wintering legumes also carry an increased risk of off-season (Sep.–June) N losses, especially during spring thaw. Spring-wheat yield among four GMr systems were evaluated with respect to off-season (GMr; Sep.–June) and in-season (wheat; June–Sep.) N2O emissions, as well as full-year NO3– leaching and dissolved N2O losses during spring-thaw from a tile-drained sandy loam soil in Atlantic Canada over 2 rotations (2011–2013). Four GMr systems (treatments) differed in the timing and season of GMr incorporation and the use of additional N as fertilizer or manure. The majority (66%) of cumulative N2O emissions were measured during the off-season because of high N2O emissions events during spring thaw. There was no clear effect of GMr system on these emissions, which may have been a result of the pattern and duration of soil freezing and thawing. Spring thaw also coincided with the highest dissolved N2O concentrations (100–300 µg N2O-N L–1) in tile-drained water, which represented potential N2O emissions of 21 to 116 g N2O-N ha–1. Belowground N2O concentrations and soil water content measurements during winter provided further evidence of the relationship of N2O dissolved in drainage water and N2O emissions at the soil surface. Wheat yield among treatments in either year of study were not different, but was 1.5 times greater in Year 2 (2.62 ± 0.27 Mg ha–1), than Year 1 (1.05 ± 0.12 Mg ha–1). The highest NO3– concentrations in drainage water (Oct.; 13.8 mg NO3–-N L–1) were measured from the GMr system with the earliest fall incorporation (i.e., Sep.) and the addition of spring fertilizer when compared to the mean of all other treatments (9.8 mg NO3–-N L–1). The use of supplemental N did not translate into additional gains in yield, yet increased in-season N2O emissions and greater NO3– leaching. Off-season N losses proved to be a substantial part of the annual N loss budget and dissolved N2O in drainage water was identified as an additional pathway for N loss at spring thaw.en_US
dc.language.isoengen_US
dc.subjectN2Oen_US
dc.subjectgreen manureen_US
dc.subjectover-winteren_US
dc.subjectnitrate leachingen_US
dc.subjectdissolved N2Oen_US
dc.titleCharacterizing nitrogen losses to air and drainage water from red clover managed as green manure or forageen_US
thesis.degree.departmentSoil Scienceen_US
thesis.degree.disciplineSoil Scienceen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberBurton, Daviden_US
dc.contributor.committeeMemberKnight, Dianeen_US
dc.contributor.committeeMemberSiciliano, Steveen_US
dc.contributor.committeeMemberShirtliffe, Steveen_US


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