Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
11 results
Search Results
Item Does temporary land retirement promote organic adoption? Evidence from expiring conservation reserve program contracts(Montana State University - Bozeman, College of Agriculture, 2022) Wing, Hannah Rose; Co-chairs, Graduate Committee: Kate Fuller and Daniel P. BigelowThe Conservation Reserve Program (CRP) is a temporary land retirement program that allows producers to remove environmentally sensitive farmland from agricultural production in exchange for a yearly rental payment. While enrolled in the CRP, land is, by definition, not being used for production and therefore typically complies with standards for organic certification. In order for an operation to become certified organic, producers must comply with organic practices for 36 months prior to when production can be labeled organic. Among other requirements, operators transitioning to organic production cannot apply synthetic pesticides or fertilizers to the land. However, some of the costly three-year transition period can be avoided through participation in the CRP as land enrolled in the program may be eligible to become certified organic in the year that it exits the program. In this paper, we study the extent to which CRP enrollment promotes organic certification. We find that CRP contract expiration leads to increases in organic adoption, and estimate a 0.157 percent increase in new organic operations in response to a 10 percent increase in expiring CRP contracts.Item Water quality response to water and nitrogen movement through a semi-arid dryland agroecosystem in Montana, USA(Montana State University - Bozeman, College of Agriculture, 2020) Sigler, William Adam; Chairperson, Graduate Committee: Stephanie A. Ewing; Stephanie A. Ewing, Clain A. Jones, Robert A. Payn, E.N. Jack Brookshire, Jane K. Klassen, Douglas Jackson-Smith and Gary S. Weissmann were co-authors of the article, 'Connections among soil, ground, and surface water chemistries characterize nitrogen loss from an agricultural landscape in the upper Missouri River Basin' in the journal 'Journal of hydrology' which is contained within this dissertation.; Stephanie A. Ewing, Clain A. Jones, Robert A. Payn, Perry Miller and Marco Maneta were co-authors of the article, 'Water and nitrate loss from dryland agricultural soils is controlled by management, soils, and weather' submitted to the journal 'Agricultural ecosystems & environment' which is contained within this dissertation.; Stephanie A. Ewing, Scott D. Wankel, Clain A. Jones, Sam Leuthold, E.N. Jack Brookshire and Robert A. Payn were co-authors of the article, 'Drivers of denitrification across a semiarid agroecosystem revealed by nitrate isotopic patterns' which is contained within this dissertation.Humans have increased reactive nitrogen (N) on the planet by an order of magnitude over the past 150 years. Most of this reactive N is used for fertilizer to feed a growing population, but loss of N from cultivated soils threatens agricultural and environmental sustainability. Nitrate accumulated in soil from fertilization or decomposition of soil organic N (SON) may be lost via leaching, which can reduce soil fertility and compromise water quality. Nitrate concentrations commonly exceed human drinking standards in groundwater resources around the globe. In the Judith River Watershed (JRW) in central Montana, nitrate has been detected above the standard since the 1960s. This dissertation contributes to a more holistic understanding of the fate and transport of N in the JRW. An interdisciplinary team engaged with farmers in a participatory research project, making observations in soils, groundwater, and streams to characterize water and N movement. At the landform scale, 5 to 9 cm yr -1 of the 38 cm yr -1 mean annual precipitation moves through soil to recharge groundwater and leaches 11 to 18 kg ha -1 yr -1 of nitrate-N from soil. These leaching rates are approximately 20-30% of fertilizer rates but likely reflect inmixing of nitrate from SON decomposition. Soil modeling analyses suggested that water and N losses were dominated by intense precipitation periods on wetter soils, such that more than half of simulated deep percolation and leaching occurred in two of 14 model years. Simulations further suggest that thinner soils (<25 cm fine-textured materials) experience water and nitrate loss rates five to 16 times higher than thicker soils (>100 cm). Soil sampling demonstrated that increased soil water during fallow periods facilitates conversion of SON to nitrate. Soils are then primed for water and N loss with subsequent precipitation, resulting in disproportionately high leaching rates during and following fallow periods. Isotopic evidence from fallow periods further suggests that nitrate is lost to the atmosphere via denitrification, a gas phase loss combining with leaching losses to compromise the goal of delivering N to crops. These findings suggest that reduction of fallow increases N use efficiency and reduces nitrate loss to groundwater.Item Investigating the impacts of agricultural land use change on regional climate processes in the northern North American Great Plains(Montana State University - Bozeman, College of Agriculture, 2021) Bromley, Gabriel Trees; Chairperson, Graduate Committee: Paul C. Stoy; Jack Brookshire (co-chair); Tobias Gerken, Andreas F. Prein and Paul C. Stoy were co-authors of the article, 'Recent trends in the near-surface climatology of the northern North American Great Plains' in the journal 'Journal of climate' which is contained within this dissertation.; Andreas F. Prein, Shannon Albeke and Paul C. Stoy were co-authors of the article, 'Simulating the impacts of agricultural land use change on the climate of the northern North American Great Plains: validating a convection-permitting climate model' submitted to the journal 'Climate dynamics' which is contained within this dissertation.; Andreas F. Prein, Shannon Albeke and Paul C. Stoy were co-authors of the article, 'The decline in summer fallow in the northern plains cooled near-surface climate but had minimal impacts on precipitation' submitted to the journal ' ' which is contained within this dissertation.; Andreas Prein and Paul C. Stoy were co-authors of the article, 'Recent enhancement of thermodynamic environments in the northern North American Great Plains' submitted to the journal 'Geophysical research letters' which is contained within this dissertation.The northern North American Great Plains (NNAGP) is the area defined by the Upper Missouri River Basin and the Canadian Prairies. It is a semi-arid region categorized by large stretches of grassland, pasture, and crops. During the last century and extending to the present day, a standard agricultural practice was to utilize a wheat-summer fallow rotation schedule, where the fields were left unplatted and an herbicide was often applied to keep weeds at bay. Concerns over soil health and profitability have led to the systematic decline of summer fallow, and nearly 116,000 km 2 that used to be fallow during the summer in the 1970s are now planted. An observational analysis discovered that from 1970-2015, during the early warm season, the NNAGP have cooled at -0.18 °C decade -1, nearly the same magnitude as the annual global warming rate. The near-surface atmosphere also moistened, evidenced by a decreasing vapor pressure deficit (VPD) trend, and monthly mean precipitation increased in excess of 8 mm per decade. Monthly mean convective available potential energy (CAPE) increased by 80% at Glasgow, MT and by 35% at Bismarck, ND based on atmospheric sounding observations. To test whether a reduction in summer fallow is responsible for these observed changes, a set of convection-permitting model experiments were performed over the NNAGP. Two sets (4 total) of three-year simulations were driven by ERA5 data with the vegetative fraction adjusted using satellite estimated fallow amounts for 2011 and 1984. The control simulations were extensively validated against an ensemble of observations with large temperature biases in Winter by ~ -3 °C and Summer by ~3°C. The areas where fallow area declined from 1984-2011 were cooler by about 1.5 °C and had a lower VPD by 0.15 kPa compared to where it did not. CAPE increased where fallow declined from 1984-2011 but so did convective inhibition (CIN). These findings insinuate that the observed change to monthly mean precipitation cannot be explained by summer fallow reduction alone. Trends in observed low level moisture transport show that the Great Plains Low Level Jet has been intensifying, bringing increased moisture to the NNAGP and partially responsible for the precipitation increase.Item Effect of summer fallowing, perennial crop cover and conservation reserve practices on soil nitrate distribution(Montana State University - Bozeman, College of Agriculture, 1994) Pannebakker, Lynn S.; Chairperson, Graduate Committee: Jim BauderDryland agriculture is an economically feasible method of producing crops in some parts of the semi-arid regions of the mid-west and western United States. Summer fallowing, which is commonly practiced in these regions, serves to replenish soil moisture and plant-available nitrate-nitrogen (N0 3--N), while also stabilizing production and more uniformly distributing the work load. In areas where dryland agriculture is concentrated, summer fallowing may lead to N0 3--N contamination of ground-water due to lack of plant uptake of excess water and N. Under certain conditions of precipitation, soil percolation, slope, and cropping intensity, summer fallowing has been shown to cause elevated N03--N concentrations in shallow groundwater wells. These elevated N0 3--N levels have been detected in several areas of the U.S. Two areas where high N0 3--N concentrations have been repeatedly found in groundwater samples are in northeastern and central Montana. Judith Basin and Fergus Counties of Montana were selected for soil sampling to assess any differences in soil NO3--N concentrations under three different land use systems: 1) crop fallow rotation, 2) acreage enrolled in the USDA Agricultural Stabilization and Conservation Service (ASCS) conservation reserve program (CRP), 3) and rangeland. Soil samples were collected to a depth of three m (10 ft) at four different sites in each county. Soil samples from all sampling depths at each of the eight sites were analyzed for gravel percent (>2 mm diameter) , N0 3--N load, and N0 3--N concentration. Samples from 0 m to 0.6 m were also analyzed for total-N concentration. Trends in soil N0 3-N give evidence that summer fallowing may be the cause of N0 3--N in shallow groundwater in some areas Of Montana where dryland cropping is practiced. Overall, average soil N0 3--N concentration throughout the sampled soil profile was 4.2, 2.0, and 1.3 mgkg-1 for the crop fallow, CRP, and rangeland land use practices, respectively. Average N0 3--N concentration in Fergus County ranged from 2.5 mgkg-1 to 20.4 mgkg-1 under crop fallow while it ranged from only 0.9 to 6.2 mgkg-1 and from 0.9 to 4.2 mgkg-1 for the CRP and rangeland uses, respectively. Average N0 3--N concentration in Judith Basin County ranged from 1.4 mgkg-1 to 6.9 mgkg-1, 0.6 mgkg-1 to 2.0 mgkg-1, and from 0.8 mgkg-1 to 1.4 mgkg-1 under crop fallow, CRP, and rangeland land use systems, respectively. Assuming that extensive use of crop fallow causes increased N0 3--N concentrations under some conditions, alternative land use management practices may be effective in reducing N0 3--N levels in such areas.Item An evaluation of nontillage and chemical fallow in small grain production(Montana State University - Bozeman, College of Agriculture, 1976) Wilson, Daniel GrantItem Yield and protein response of spring wheat (Triticum aestivum L.) to nitrogen fertilizer and the cycling of labelled fertilizer N with fallow and recrop management practices(Montana State University - Bozeman, College of Agriculture, 1978) Jones, Alice J.Item The impact of integrating sheep into wheat farming systems to manage wheat stem sawfly Cephus cintus (Hymenoptera: cephidae) and weeds(Montana State University - Bozeman, College of Agriculture, 2003) Spezzano, Theresa Marie; Chairperson, Graduate Committee: Patrick G. Hatfield.Item Mineralization of nitrogen and carbon in adjacent crop-fallow and native range soils(Montana State University - Bozeman, College of Agriculture, 1995) Neill, Karnes EdwinItem Chemical fallow in Montana(Montana State University - Bozeman, College of Agriculture, 1981) Brattain, Robby LeeItem Microwave sterilization of weed seeds(Montana State University - Bozeman, College of Engineering, 1982) Gliko, Stanley Mark