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Item Pest management challenges and climate change in water limited winter wheat agroecosystems in southwestern Montana(Montana State University - Bozeman, College of Agriculture, 2020) Nixon, Madison Grace; Chairperson, Graduate Committee: Fabian D. MenalledDryland winter wheat production is influenced by many environmental factors including climate, disease, and resource availability. In Montana, Bromus tectorum (cheatgrass) and Fusarium pseudograminearum (a fungus causing root crown rot) are major winter wheat pests; reducing yield and grain quality. However, little is known how climate change and resource availability impact winter wheat, B. tectorum, and F. pseudograminearum individually as well as their multi-trophic interactions. Thus, this research aimed to 1) Determine the susceptibility of B. tectorum to F. pseudograminearum and assess how CO 2 and nitrogen impact their growth, and 2) Evaluate how elevated temperature, reduced precipitation, and plant competition impact winter wheat and B. tectorum growth and reproduction. Utilizing growth chambers, high and low nitrogen treatments, fungal inoculated and uninoculated treatments, and ambient and elevated CO 2 treatments, Bromus tectorum was found to be a host of F. pseudograminearum, and the fungus significantly reduced root, shoot and total biomass, as well as primary physiological processes of B. tectorum. Fusarium pseudograminearum infection was not impacted by nitrogen or CO 2 level. Low nitrogen increased emergence and root production early on, while high nitrogen increased shoot production at later growth stages. Low nitrogen also improved stomatal conductance and transpiration rate. High CO 2 increased B. tectorum root, shoot, and biomass production, as well as intercellular CO 2. An interaction between ambient CO 2 and low nitrogen resulted in the greatest shoot relative growth rate between the first and second harvest. Field tests, using three climate treatments (ambient, increased temperature, reduced precipitation with increased temperature) and three plant competition levels (monoculture winter wheat, monoculture B. tectorum, and biculture of the two), found that for both winter wheat and B. tectorum monocultures, ambient and warmer climates produced similar yields and biomass, respectively, whereas the drier with warmer treatment reduced these factors. Additionally, B. tectorum presence increased winter wheat grain protein. A quadratic interaction model of winter wheat yield as a function of B. tectorum biomass by climate treatment suggests that at low to moderate B. tectorum biomass levels, winter wheat yield was negatively impacted by the warmer and drier treatment, whereas ambient and warmer treatment results were similar.Item The costs of cooperation: the effects of section 199 on basis for farm cooperatives in the midwest(Montana State University - Bozeman, College of Agriculture, 2019) Swanson, Andrew Chase; Chairperson, Graduate Committee: Anton BekkermanThe 2004 American Jobs Creation Act created Section 199, a tax provision for producers of domestic goods. During the ensuing decade, Section 199 became especially important for agricultural cooperatives, partly because of a series of favorable Internal Revenue Service private letter rulings for marketing cooperatives. I analyze the impacts of Section 199 on agricultural markets by assessing differential effects on the pricing behavior of grain marketing cooperatives and non-cooperatives in Nebraska and Kansas. I first develop a model for the agricultural cooperatives pricing behavior that incorporates a tax on the qualified patronage received by cooperative patrons. This model produces several testable predictions. First, Section 199 will lower the spot prices offered by cooperatives while increasing the spot prices offered non-cooperatives that compete with cooperatives for agricultural commodities. Second, the widening of prices between cooperatives and non-cooperatives will be mitigated by increased spatial competition. I empirically test the predictions of this model using a difference-in-difference empirical strategy and winter wheat basis data. The results indicate that the series of IRS letter rulings in 2008 widened the basis differential between cooperative and non-cooperative firms by almost 5 cents per bushel on average. Furthermore, these market distorting effects are greater for elevator locations that do not have a competing location within 10 miles of their location. While the benefits of Section 199 have been widely touted by cooperative lobbying groups, the results of this thesis show the importance of also considering the costs of policy interventions directed at specific agricultural firm types.Item Cycling and storage of reactive soil carbon and nitrogen pools: management implications for semiarid crop production(Montana State University - Bozeman, College of Agriculture, 2017) Romero, Carlos Matias; Chairperson, Graduate Committee: Richard E. Engel; Richard 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.; Richard 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.; Richard 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.; Richard 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.Changes 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.Item Characterizing the effect of USDA report announcements in the winter wheat futures market using realized volatility(Montana State University - Bozeman, College of Agriculture, 2015) Bunek, Gabriel David; Chairperson, Graduate Committee: Joseph JanzenThe United States Department of Agriculture provides information about fundamental supply and demand conditions for major agricultural commodities. I consider whether USDA's crop reports facilitate price consensus in the winter wheat futures market by testing the hypothesis that uncertainty, as measured by realized price volatility is reduced following the release of USDA reports. This hypothesis was originally developed in studies using implied volatility and found significant decreases. I instead calculate realized daily and intraday volatility using transaction level data from Kansas City Board of Trade futures contracts. Dates on which USDA reports are released are compared to the ten days around the report. Exploiting the full granularity of data, intraminute volatilities are computed to test whether there are distributional differences between report and non-report days. All results suggest that realized volatility does not decrease following USDA wheat report releases but instead increases. Regression analysis shows this result is robust to the inclusion of a limited but relevant set of controls.Item Breeding for root lesion nematode resistance in Montana winter wheat(Montana State University - Bozeman, College of Agriculture, 2015) May, David Bruce, III; Chairperson, Graduate Committee: Philip L. BrucknerRoot lesion nematodes (RLN; Pratylenchus spp.) present a serious challenge to dryland wheat production worldwide. Development of resistant cultivars would provide great economic benefit to growers. From 2012-2013, a set of backcross lines (MT08185//MT08184/Persia 20) was screened twice for resistance to P. neglectus. Progeny and parent lines were grown in infested soil for 16 to 18 weeks. Nematodes were then extracted from roots of individual plants and counted to obtain per plant final populations. ANOVA results from the 2013 screen showed significant differences in mean P. neglectus populations among lines (p < 0.01). The median final population of susceptible parent MT08184 was an estimated 4.9 times greater than that of resistant parent Persia 20. A 2013 field trial in the absence of root lesion nematodes indicated reductions in grain yield, volume weight, and protein were not associated with resistance. Seven RLN-resistant lines were identified in field evaluations with agronomic phenotypes for yield, volume weight and protein comparable to those of five widely-grown checks. Identification of quantitative trait loci (QTL) for resistance to RLN will facilitate marker-assisted introgression of resistance genes in a backcross-breeding program. Single-marker analysis of 218 genome-wide single nucleotide polymorphism markers (SNPs) was performed to identify genomic regions associated with resistance to P. neglectus. The analysis identified putative marker-trait associations on chromosomes 1AL, 1DS, 2BL, 5BL, 5DL, 7AL and 7DL (all p < 0.05). Overall, phenotypic screens as applied were inadequate to consistently characterize wheat lines for RLN resistance. As such, RLN resistance phenotypes and putative QTL effects identified in the study must be verified in future experiments.Item Genetic determinations in winter wheat Triticum aestiyum L. em. Thell. aneuploids using serological techniques(Montana State University - Bozeman, College of Agriculture, 1968) Volin, R. B.Item The effect of simulated drought on stem-stored carbohydrate characteristics in winter wheat(Montana State University - Bozeman, College of Agriculture, 1989) Sabry, Sami Reda SaberItem Development of chemical tests for soil nitrate content as a factor for correlating soil and climatic properties with winter wheat (Triticum aestivum L.) yield(Montana State University - Bozeman, College of Agriculture, 1970) Jackson, Grant D.Item Influence of soil profile and site characteristics on the response of winter wheat to K on Montana soils(Montana State University - Bozeman, College of Agriculture, 1979) Schaff, Bernard EugeneItem Soil and terrain attributes for predicting soil fertility and winter wheat yield(Montana State University - Bozeman, College of Agriculture, 1993) McEachern, Kirk Lowndes