Theses and Dissertations at Montana State University (MSU)
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Item Interactive effects between lime, organic matter, and bacteria in the establishment of Leymus cinereus in mine tailings(Montana State University - Bozeman, College of Agriculture, 2015) Sanchez Espinoza, Deicy Noemi; Chairperson, Graduate Committee: Anthony HartshornThe landscape legacy of historical metal-mining activity can persist for decades. The most frequent strategies used for the remediation of contaminated soils include: the use of synthetic membranes to isolate contaminants (>$0.5 million/acre), direct revegetation (less expensive but difficult to sustain), or lime amendments ($5000/acre). Looking for more cost-effective bioremediation approaches, we performed a set of greenhouse studies to determine what combinations of soil amendments would lead to the best vegetative response, and potentially associated reductions in soil arsenic (As) levels, in "slickens" collected from the Lampert Ranch along the upper Clark Fork near Warm Springs, MT. In our first greenhouse experiment, we planted Leymus cinereus (basin wildrye) and compared (after 12 weeks) plant growth and foliar metal concentrations across treatments. Amendments included single or factorial additions of 5% lime, organic matter (+OM), and an arsenic-oxidizing (+oxbact) strain of Agrobacterium tumefaciens (Agtu). Surprisingly, the OM+oxbact treatment revealed among the best plant growth and arsenic uptake response. We then performed a second greenhouse experiment with two levels of OM (1.5% and 5%) and an additional treatment: a mutant (reducing strain) of Agtu. Basin wildrye grown in soils amended with 5% OM generally did better than those grown in soils amended with 1.5% OM. At the same time, foliar As uptake (biomass multiplied by As concentration) was unexpectedly high (0.020 mg pot-1) for plants grown in soils amended with 5% OM + oxbact, 3 times greater than foliar arsenic uptake in plants grown in soils amended with 5% OM+ lime and 4 times greater than foliar uptake by plants grown in soils amended with 5% OM and the reducing strain of Agtu. These results suggest the combination of OM and Agtu oxbact strain could provide a potentially cost- effective approach to remediating As-contaminated soils. Finally, our study results imply that soil restoration approaches could be improved through a greater consideration of microbial communities supported by these re-establishing vegetation communities, which could lead to more sustainable ecosystem successional trajectories.Item Reclamation of abandoned bentonite mine spoils with phosphogypsum and magnesium chloride amendments(Montana State University - Bozeman, College of Agriculture, 1988) Smith, Steven Carl; Chairperson, Graduate Committee: Douglas J. DollhopfAbandoned bentonite mine spoils are scattered over southeast and north central Montana. The clayey, saline-sodic nature of these spoils creates adverse physicochemical properties. Invasion of native plant species is precluded and revegetation is difficult. Infiltration of surface water is severely limited due to surface crusting and shrink-swell processes. Chemical amendments have recently been shown to be effective in ameliorating adverse physical and chemical spoil properties. Chemical amendment use increases reclamation costs significantly, therefore effective, low cost amendments are needed. Phosphpgypsum and magnesium chloride brine are low cost industrial wastes that have not been tested for use in land reclamation. Experimental field plots were implemented to evaluate the effects of phosphogypsum (40.4 mt/ha) and magnesium chloride brine (36.2 mt/ha) incorporated to a 35 cm depth. Effects of nitrogen fertilizer (0, 67 kg/ha, and 134 kg/ha) on seedling emergence were also tested. Representative unamended spoil at the site had a sodium adsorption ratio (SAR) of 33.8 and an electrical conductivity (EC) of 8.0 mmhos/cm. Over a 14 month sampling period, SAR (0-5 cm) declined to 24.5 on phosphogypsum treated plots, and to 21.3 on magnesium chloride brine treated plots. Electrical conductivity (0-5 cm) increased to 10.1 mmhos/cm on phosphogypsum treated plots, and to 15.9 mmhos/cm on magnesium chloride brine treated plots. Following 30 minutes of simulated rainfall, minesoil infiltration rates were 2.8 cm/hr on phosphogypsum treated plots and 3.8 cm/hr on magnesium chloride brine treated plots, compared to .1 cm/hr on unamended spoil. Nitrogen fertilizer at 67 kg/ha resulted in significantly greater seedling density among fertilizer treatments, at 192 seedlings/m^2. Plant canopy cover of 39% estimated on magnesium chloride brine treated plots was significantly greater than 28% on phosphogypsum treated plots. Above ground plant production was 1753 kg/ha on phosphogypsum treated plots and 2717 kg/ha on magnesium chloride brine treated plots. Production of pioneering (non-seeded) annual forbs comprised 60% of total production on phosphogypsum treated plots and 83% on magnesium chloride brine treated plots.Item Reclamation of calcareous saline-sodic soils in southcentral Montana with by-product sulfuric acid(Montana State University - Bozeman, College of Agriculture, 1979) Cates, Richard LymanItem The potential for dryland alfalfa on minesoils in southeastern Montana(Montana State University - Bozeman, College of Agriculture, 1985) Postle, Robert CairnsItem A Comparison of greenhouse methods as diagnostic tools for reclamation planning(Montana State University - Bozeman, College of Agriculture, 1984) Byron, Timothy MartinItem A computerized automated rapid weathering apparatus for determining total lime requirements for acid minesoils(Montana State University - Bozeman, College of Agriculture, 1985) Harvey, K. C.Item Development of wildlife habitat on mined lands(Montana State University - Bozeman, College of Agriculture, 1982) Carlson, Robert Steven; Chairperson, Graduate Committee: Frank Munshower.Item Hydrology of a waste rock repository capping system at the Zortman Mine(Montana State University - Bozeman, College of Agriculture, 1997) Warnemuende, E. A.Item Effect of two dolomitic industrial by-products on pH control, leachate chemistry and plant response in acidic-metalliferous mine waste(Montana State University - Bozeman, College of Agriculture, 1997) Kelly, Laureen SusanItem Suitability of an alluvial overburden material as a plant growth medium at the Berkeley Complex in Butte, Montana(Montana State University - Bozeman, College of Agriculture, 1984) Lawson, John Allen
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