Theses and Dissertations at Montana State University (MSU)
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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 Soil water, nitrate, and site characteristics of Montana foothills range(Montana State University - Bozeman, College of Agriculture, 1976) Haigh, June G.Item Near real-time satellite and ground based radiometric estimation of vegetation biomass, and nitrogen content in Montana rangelands(Montana State University - Bozeman, College of Agriculture, 1998) Thoma, David P.Item Measuring ecosystem integrity in agroecosystems and rural communities(Montana State University - Bozeman, College of Agriculture, 1997) Knox, David Ernest; Conservation Reserve Program (U.S.)Item Characterizing rangeland using multispectral remotely sensed data and multi-scale ecological units(Montana State University - Bozeman, College of Agriculture, 2003) Maynard, Catherine Cae Lee; Chairperson, Graduate Committee: Rick Lawrence.Item The effects of mechanical treatment on the soils and vegetation of a Natrargid-Paleargid complex in Northern Montana(Montana State University - Bozeman, College of Agriculture, 1981) Boehm, Marie MargaretItem Using canines to detect spotted knapweed : field surveys and characterization of plant volatiles(Montana State University - Bozeman, College of Agriculture, 2010) Goodwin, Kim Marie; Chairperson, Graduate Committee: Richard E. Engel; David K. Weaver (co-chair); Rick E. Engel and David K. Weaver were co-authors of the article, 'Trained dogs outperform human surveyors in the detection of rare spotted knapweed (Centaurea stoebe)' in the journal 'Invasive plant science and management' which is contained within this thesis.Invasive plants threaten biodiversity as well as the function of ecosystems and cause loss for land users and managers in western North America. Eradication of invasive plant populations is desirable to prevent these impacts. But eradication is difficult to attain due to imprecise detection rates for low density and inconspicuous plants, such as juveniles and small adult plants. In an effort to improve the accuracy of plant detection, we investigated the ability of domestic dogs (Canis familiaris L.) to search for and detect rare occurrences of spotted knapweed (Centaurea stoebe L). The objectives of this study were to (1) compare the performance of trained dogs to human surveyors in detecting new invasions of knapweed, (2) evaluate the ability of the dogs to detect below ground odor produced by knapweed roots, and (3) characterize the above and below ground volatile profiles of spotted knapweed. The accuracy of three dogs was compared to human surveyors on a dryland pasture near Belgrade, Montana in 2005 and 2006. Dog accuracy for large-size knapweed infestations (0.52m ³) was similar to human accuracy and better than humans (94 vs. 78%) for medium-size infestations (0.13 m ³). Dog accuracy (67%) was greater (>81% probability) than humans (34%) for small knapweed targets (plants; 0.02 m ³). In September 2006, controlled odor response experiments were conducted in a livestock barn in Bozeman, Montana to evaluate the ability of the dogs to identify spotted knapweed root material without being previously trained to do so. Mean success rate of the dogs to recognize bare and intact roots were 97% and 87% respectively. In 2005 and 2006, volatile collections were conducted. The main compounds of the foliage were found to be (Z)-3-hexenyl acetate, beta-cis-ocimene, and beta-cubebene, which were not present in the roots. The main constituents of the roots were junipene, beta-caryophyllene, and thujopsene, which were not present in the foliage (exception: beta-caryophyllene), indicating dissimilar volatile profiles between the foliage and the roots. Collectively, these results indicate detection dogs might improve the efficiency and accuracy of plant detection by increasing the likelihood small and inconspicuous plants, including belowground plant targets, will be detected.Item Vegetation dynamics in Yellowstone's Northern Range : 1985 - 1999(Montana State University - Bozeman, College of Agriculture, 2005) Savage, Shannon Lea; Chairperson, Graduate Committee: Rick L. Lawrence.The Northern Range (NR) of Yellowstone National Park (YNP) is currently a critical area of analysis in the Greater Yellowstone Ecosystem (GYE). The complex dynamic ecosystems in the NR provide outstanding field laboratories for long-term scientific investigations to evaluate management techniques. Grassland and shrubland ecosystems serve as important habitat for a wide variety of animal species in the NR and empirical knowledge of these systems enables managers to better understand the ecological complexities and make informed management decisions. Accurate vegetation maps are useful tools for these land managers, as is the ability to detect changes in vegetation over time. An inexpensive and easily reproducible method for mapping rangelands over the NR was developed utilizing Landsat Enhanced Thematic Mapper Plus (ETM+) satellite imagery. A classification hierarchy of non-forest vegetation was produced with 5 levels, ranging from very broad vegetation types such as woodland, shrubland, or herbaceous vegetation (Level 1) to specific vegetation types such as aspen (Populus tremuloides), tufted hairgrass/sedge (Deschampsia cespitosa/Carex spp.), or big sagebrush/Idaho fescue (Artemisia tridentata/Festuca idahoensis) (Level 5). A 1999 base map of nonforest vegetation in the NR was created using classification tree analysis (CTA) combined with boosting. Overall accuracies of the final maps ranged from 72.30% for Level 5 to 83.65% for Level 1, providing evidence that this method can be successful for mapping non-forest vegetation in the NR. A 1985 Landsat Thematic Mapper (TM) satellite image was chosen for performing a change detection analysis from 1985 to 1999. Tasseled Cap space was utilized to choose a threshold of change in a change vector analysis (CVA). Areas of no change in the 1999 image were used to train areas of potential change on the 1985 image to produce a final map of the NR for 1985. Overall accuracies of the final maps ranged from 72.60% for Level 5 to 88.73% for Level 1. Managers are able to analyze this change information and modify their management techniques as needed. With the 1999 base map the CVA method enables managers to detect vegetation change in the NR on a regular basis.Item The effects of riparian grazing exclosures on adjacent riverine ecosystems(Montana State University - Bozeman, College of Agriculture, 2011) Bunn, Victoria Jeanne; Chairperson, Graduate Committee: Duncan T. Patten; Geoffrey Poole (co-chair)In the western U.S., riparian ecosystems cover 1% of land area while supporting 70-80% of native species. 70% of this land area is available as range for livestock, who use riparian areas preferentially. Ecological concerns have led to numerous studies of the effects grazing has on these ecologically important, easily damaged ecosystems. Exclosure-based research has thoroughly examined the effects of livestock on riparian ecosystem health and function, but failed to investigate the potential for exclosures to intensify adverse effects of use at their boundaries, which could lead to overestimation of their benefits and impair their efficacy in management. This study attempts to supplement existing research by characterizing potential impacts, making exclosures a more informed and effective management strategy. Study exclosures were located on grazed public lands in southwest Montana. Riparian vegetative cover and channel morphology response variables were measured inside the exclosure and in two grazed reaches, one placed 0 to 20 m and one >50 m from the exclosure to capture differences in the spatial extent and severity of any impacts due to differences in livestock behavior caused by the exclosure's influence. Findings were that (1) results were consistent with previous exclosure studies using the same response variables to compare grazed and exclosed areas, (2) significant differences in herbaceous cover, bare ground cover, channel width, and bank angle between the two grazed subreaches were greater than corresponding grazed/exclosed comparisons, indicating that impacts to the subreach adjacent to the exclosure that are greater than corresponding improvements within, (3) spatially inconsistent impact zones within and among sites made it impossible to describe an overall impact zone adjacent to exclosures, but impacts to channel morphology, herbaceous cover, and bare ground occurred within 8 m of the exclosure, and within 2 m for bank angle, (4) data didn't support predicted relationships between impact severity and exclosure duration, size, or stocking rates, most likely due to the many other influencing factors that were not measured. Evidence supporting existence of exclosure-caused impacts should inform exclosure use and make it a more effective management tool, especially when considered in the context of how these impacts might encumber specific management goals.