Theses and Dissertations at Montana State University (MSU)
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Item Patch habitat contributions to biodiversity, ecosystem services, and crop production in the Northern Great Plains(Montana State University - Bozeman, College of Agriculture, 2023) Duff, Hannah Katherine; Chairperson, Graduate Committee: Bruce D. Maxwell; This is a manuscript style paper that includes co-authored chapters.In response to global calls for sustainable food production and biodiversity conservation, we explored the potential of conserving small non-crop patch habitats, or ecological refugia, to meet food production and conservation objectives within agroecosystems. This dissertation considered multi-objective outcomes of conserving ecological refugia within dryland grain production systems in the Northern Great Plains (NGP) that included agronomic, ecological, and economic tradeoffs, and policy implications. First, we proposed the union of production oriented and ecologically oriented agriculture within a precision agroecology framework. We advocated for the merger of precision agriculture technology and agroecological principles to transform food systems. First, we explored the potential to incorporate biodiversity into crop fields using precision conservation to conserve low-yield areas as patch habitat and manage for sub-field variation. Second, we found that small ecological refugia increased plant and arthropod diversity, provided ecosystem service tradeoffs, and enhanced crop yield, but not crop quality in three dryland grain production systems in the NGP. Third, we found that local biodiversity response to landscape context was scale-dependent, and that correlations between landscape variables and local biodiversity were lowest at the most distant extent (< or = 5km from the ecological refuge). Partial R-squared values were highest when both local and landscape variables were included, and when composition and configuration variables were included in models predicting local biodiversity. These results suggested that local conservation efforts should be coordinated with landscape-level efforts to enhance biodiversity and ecosystem service provision across agricultural landscapes. Last, we found that removing low-yielding portions of crop fields from production could provide positive returns on investment to farmers but profitability depended on the size of the patch removed, harvest year, grain price received, potential yield gain associated with ecosystem services, and government conservation program incentives. Additional noneconomic policy levers may be needed to incentivize adoption of on-farm conservation practices. Looking forward, ecological refugia have the potential to host biodiversity, increase agroecosystem functioning, and benefit crop production. Future research should investigate site-specific practices for patch habitat conservation, determine effective incentives for on-farm conservation, and coordinate landscape-scale efforts to create and connect agroecological landscapes.Item Role of crop fertility and seed treatments in managing fusarium root rot of lentil (Lens culinaris Medikus) in the northern Great Plains(Montana State University - Bozeman, College of Agriculture, 2021) Atencio, Sydney Christine; Chairperson, Graduate Committee: Perry Miller and Mary Burrows (co-chair)Lentil is a relatively new but economically important crop for the state of Montana, along with surrounding states in the northern Great Plains. Comparatively little is known about the basic fertility of lentil, and importance of inoculant type on lentil. Additionally, the rise of pulse crop acres in the northern Great Plains, has given rise to root rot pathogens, such as Fusarium root rot. Fusarium root rot of pulses, has a wide host range, limiting the efficacy of rotation in its management. This research is comprised of two main studies. Field trials occurred at sites in Bozeman, Havre, Moccasin, and Sidney in 2019 and 2020. The objective of chapter two was to evaluate the effect of rhizobial inoculant formulations (granular vs. seed-coat/peat-powder) and nutrient additions (potassium, sulfur, and a micronutrient fertilizer), on lentil establishment, growth, seed protein, and yield. For chapter two, in six of eight site-years there was no yield difference between inoculant types. Applications of sulfur (S) fertilizer increased yield at three of eight site-years by an average of 303 kg ha-1 (17%) compared to treatments without S. Results from this study further suggest the importance of S fertilization for lentil. The objective for chapter three was to evaluate seed treatments' ability to control Fusarium root rot on lentil establishment, growth, disease severity and yield. In three of eight site-years, the inoculated control had a relatively high disease severity compared to other seed treatments. In general, treatment responses varied across site-year due to low disease pressure. Additionally, F. graminearum and F. oxysporum were isolated at a high frequency from control plots at sites in 2019. Data from 2020 is pending.Item Effect of spectral band selection and bandwidth on weed detection in agricultural fields using hyperspectral remote sensing(Montana State University - Bozeman, College of Agriculture, 2017) Tittle, Samuel Bryant; Chairperson, Graduate Committee: Rick L. LawrencePresence of weeds in agricultural fields affects farmers' economic returns by increasing herbicide input. Application of herbicides traditionally consists of uniform application across fields, even though weed locations can be spatially variable within a field. The concept of spot spraying seeks to reduce farmers' costs and chemical inputs to the environment by only applying herbicides to infested areas. Current spot spraying technology relies on broad spectral bands with limited ability to differentiate weed species from crops. Hyperspectral remote sensing (many narrow, contiguous spectral bands) has been shown in previous research to successfully distinguish weeds from other vegetation. Hyperspectral sensor technology, however, might not currently be practical for on-tractor applications. The research objectives were to determine (1) the utility of using a limited number of narrow spectral bands as compared to a full set of hyperspectral bands and (2) the relative accuracy of narrow spectral bands compared to wider spectral bands. Answers to these objectives have the potential for improving on-tractor weed detection sensors. Reference data was provided by field observations of 224 weed infested and 304 uninfested locations within two winter wheat fields in Gallatin County, Montana, USA. Airborne hyperspectral data collected concurrently with the reference data provided 6-nm spectral bands that were used in varying combinations and artificially widened to address the research objectives. Band selection was compared using Euclidean, divergence, transformed divergence, and Jefferies-Matusita signature separability measures. Certain three and four narrow band combinations produced accuracies with no statistical difference from the full set of hyperspectral bands (based on kappa statistic analysis, alpha = 0.05). Bands that were artificially widened to 96 nm also showed no statistically significant difference from the use of 6-nm bands for both all bands and select band combinations. Results indicate the potential for bands that can differentiate weed species from crops and that the narrowest spectral bands available might not be necessary for accurate classification. Further research is needed to determine the robustness of this analysis, including whether a single set of spectral bands can be used effectively across multiple crop/weed systems, or whether band selection is site or system specific.Item The influence of soil series on cereal grain yield(Montana State University - Bozeman, College of Agriculture, 1986) Larson, Michael HerbertItem The establishment, drought tolerance, and weed suppression potential of multispecies sod(Montana State University - Bozeman, College of Agriculture, 2009) Stark, Jennifer Grace; Chairperson, Graduate Committee: Lisa J. Rew.Re-seeding is a frequently used technique to revegetate disturbed areas, but often leaves bare ground prone to weed invasion. Mixtures of drought tolerant or native species in sod could be used as an alternative to seed to provide rapid establishment of desirable plant communities that may potentially reduce weed emergence, survival, and productivity. Additionally, the reinforcement material required to aid transport of multispecies sod could further contribute to weed suppression and sod establishment. The objective of this study was to evaluate the weed suppression and establishment potential of multispecies sod. Three experiments were each subject to a water regime ranging from 2.54 cm of water/week to natural precipitation, and repeated over two/three years. In the first two experiments (A and B) Brassica napus (canola) was used as a surrogate weed species and sown either below the multispecies sod to represent weed seed bank, or above the multispecies sod to represent weed seed rain. In experiment A, B. napus was sown at six densities; while in experiment B reinforcement materials (nylon netting control, coconut-straw, jute, excelsior) were added below the sod and B. napus was sown at one density. B. napus suppression by multispecies sod, with or without reinforcement material, was evaluated by recording seedling emergence, survival and above-ground biomass. Multispecies sod, especially combined with reinforcement material, suppressed a large proportion of seedling emergence. The seedlings that did establish produced less vegetative and seed biomass as water decreased. In the second season of both experiments no seedlings survived to maturity. The establishment success of the multispecies sod was evaluated through repeated measures of percent sod cover over two/three years. The results suggested that the multispecies sod was able to establish and persist under natural precipitation. The third experiment evaluated the ability of multispecies sod to suppress Cirsium arvense (Canada thistle) vegetative propagules in two different habitat types, bare ground or multispecies sod, under high and low water treatments. More C. arvense shoots emerged in the bare ground, suggesting that multispecies sod could act as a buffer zone and reduce the vegetative spread of perennial weeds if used as a revegetation strategy.