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dc.contributor.advisorChairperson, Graduate Committee: Richard E. Engelen
dc.contributor.authorRomero, Carlos Matiasen
dc.contributor.otherRichard Engel, Chengci Chen and Roseann Wallander were co-authors of the article, 'Microbial immobilization of nitrogen-15 labelled ammonium and nitrate in an agricultural soil' in the journal 'Soil Science Society of America journal' which is contained within this thesis.en
dc.contributor.otherRichard E. Engel, Chengci Chen, Roseann Wallander and Clain A. Jones were co-authors of the article, 'Late-Fall, Winter, and Spring broadcast applications of urea to no-till Winter wheat II. Fertilizer N recovery, yield, and protein as affected by NBPT' in the journal 'Soil Science Society of America journal' which is contained within this thesis.en
dc.contributor.otherRichard E. Engel, Juliana D'Andrilli, Chengci Chen, Catherine Zabinski, Perry Miller and Roseann Wallander were co-authors of the article, 'Bulk optical characterization of dissolved organic matter from semiarid wheat-based cropping systems' in the journal 'Geoderma' which is contained within this thesis.en
dc.contributor.otherRichard E. Engel, Juliana D'Andrilli, Chengci Chen, Catherine Zabinski, Perry Miller and Roseann Wallander were co-authors of the article, 'The oxidizable fraction of organic matter by potassium permanganate in semiarid drylands: from soils to spectra' submitted to the journal 'Ecological Indicators' which is contained within this thesis.en
dc.coverage.spatialGreat plainsen
dc.date.accessioned2018-05-09T19:08:58Z
dc.date.available2018-05-09T19:08:58Z
dc.date.issued2017en
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/13723en
dc.description.abstractChanges in the size and distribution of soil organic carbon (C) and nitrogen (N) pools affect the biogeochemical properties of terrestrial ecosystems; particularly in semiarid drylands where environmental constraints limit crop production. Agriculture in the northern Great Plains (NGP) of North America has undergone a tillage reduction revolution over the past 20 years; it is therefore imperative to elucidate how organic matter (OM) and fertilizer-N cycle under no-till (NT) management given its potential for providing more sustainable cropping systems and mitigating environmental losses. The objective of this dissertation was to characterize the cycling of labile, reactive pools of soil organic C and N among NT wheat (Triticum aestivum L.)-based cropping systems subjected to differing cropping intensity and fertilizer-N management. We conducted both laboratory and field experiments following the fate of 15 N-labelled fertilizer as affected by N management principles. In surface soil, microbial uptake of NH 4+ was greater than for NO 3- forms. Lower immobilization of NO 3- might therefore increase fertilizer-N availability to winter wheat relative to NH 4+ or urea-based sources. In plant tissue, fertilizer-N recovery (FNR) by winter wheat was affected by application timing of urea to the soil surface; FNR was greater for spring than late-fall and winter applications. The addition of urease inhibitor N-(n-butyl) thiophosphoric triamide improved FNR of all urea timings, but the response was greater for late-fall and winter compared with spring applications. We also examined the cycling of labile, reactive OM as affected by differing land management. Specifically, we characterized dissolved organic matter (DOM) and permanganate oxidizable carbon (POXC) concentration and composition from soil samples collected from three long-term (>10 yr) cropping field sites. Annual NT cropping increased the concentration and compositional diversity of DOM and POXC pools; higher inputs of biomass-C promoted the accumulation of fresh, plant derived DOM relative to conventional fallow-wheat management. Such enrichment translated into higher OM accretion rates within the uppermost 0-50 cm layer, likely benefiting FNR by winter wheat. Our experimental approach provided a comprehensive tool for agroecosystem evaluation at the farm level, identifying NT scenarios that can be used for sustainable management frameworks within the NGP.en
dc.language.isoenen
dc.publisherMontana State University - Bozeman, College of Agricultureen
dc.subject.lcshArid regionsen
dc.subject.lcshNo-tillageen
dc.subject.lcshWinter wheaten
dc.subject.lcshCarbonen
dc.subject.lcshNitrogenen
dc.titleCycling and storage of reactive soil carbon and nitrogen pools: management implications for semiarid crop productionen
dc.typeDissertationen
dc.rights.holderCopyright 2017 by Carlos Matias Romeroen
thesis.degree.committeemembersMembers, Graduate Committee: Chengci Chen; Catherine A. Zabinski; Timothy R. McDermott; Juliana D'Andrilli.en
thesis.degree.departmentLand Resources & Environmental Sciences.en
thesis.degree.genreDissertationen
thesis.degree.namePhDen
thesis.format.extentfirstpage1en
thesis.format.extentlastpage222en
mus.relation.departmentLand Resources & Environmental Sciences.en_US
mus.data.thumbpage162en


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