This research was conducted to 1) evaluate the use of drain tile (subsurface drainage) in an irrigated and dryland management system in both a cotton and soybean production system and 2) determine an herbicide program to control Palmer amaranth (Amaranthus palmeri S. Wats.) in the absence of dicamba. Neither drainage or drainage spacing had any effect pre-plant soil conditions, plant growth parameters, or yield in either production system. Stand counts were reduced in narrow tiled spacings (4.5 m) in the dryland cotton study. However, there was no reduction in lint yield due to the reduction in plant stand. Moreover, residual control was maximized with the use of fluridone and fomesafen as PRE emergence treatments. Glufosinate provided the greatest control of Palmer amaranth in the absence of dicamba. Lint yield was maximized with the application of glufosinate in the absence of dicamba. These data indicate that subsurface drainage had no effect on cotton or soybean performance in Mississippi. Moreover, in the absence of dicamba Palmer amaranth control options can be optimized by using fluridone or fomesafen as PRE emergence applications and glufosinate as POST emergence application to minimize yield reductions due to Palmer amaranth.

No description available.

Thesis (M.S.)--Ohio State University, 1981. / Includes bibliographical references (leaves 89-91). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 193-197). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 193-197). Also available on the Internet.

Subsurface drainage affects water table fluctuation patterns by removing the excess water from the soil. The annual average water table depths of the drained (A) and undrained (D) regimes are 0.83 and 0.48 m from the soil surface respectively. Subirrigation continuously provides water to the upper soil by capillary rise. The annual water table depths of the subirrigated regimes (B and C) are 0.61 and 0.70 m respectively. It is found that there is a significant curvilinear correlationship between the drainage flow rate and the water table height above the drain. Soil drainable porosity of different regimes was investigated by using the soil water balance approach. The average drainable porosity of regimes A and B are 6.0% and 4.9% from water table rise, and 5.9% and 4.5% from water table drawdown , respectively. Subirrigation adversely affects the soil drainable porosity. Soil drainable porosity is often considered as a constant. However, the results of this study indicate that it varies with the water table height above the drain. In the case of water table drawdown, this dependence can be successfully expressed by a negative exponential equation. In the case of water table rise, the correlation is not as significant, but there is still a trend that the drainable porosity decreases with the increase of the water table height above the drain. Evapotranspiration (ET) is often neglected in soil water balance models for the drain-able porosity determination. This may result in some errors. In this study, the potential ET rate was computed by the Penman and Hargreaves methods. These two methods give very similar ET values for the studied area. It is assumed that actual ET equals to the potential ET rate when the ground water table is close to the soil surface. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

The objective of this thesis was to characterize the microbiology of subsurface fracture water at a location within the Canadian Shield considered as a prospective host site for a geologic repository. Repository performance and long-term safety predictions for geologic confinement of radioactive waste rely on understanding the natural microbial processes that occur within a host formation; however, the inaccessibility of the crystalline terrestrial subsurface means that this habitat is difficult to explore and as such is largely unknown. The area characterized is located within the boundary of the Chalk River Laboratories site, situated within the Central Gneissic Belt of the Grenville province (formed 1.5 and 1.0 ba years before present); the site is also situated within the Ottawa-Bonnechere graben (formed 0.5 ba before present). Fracture water was accessed from one 34 m deep open drill hole and six cased and sealed drill holes; the Westbay Multilevel Groundwater Monitoring system preserved the natural fracture flow enabling discrete fracture water sampling at multiple depths via each of the sealed drill holes. This thesis combined multiple datasets in an exploratory analysis for drivers of subsurface microbial assembly within an ecological framework of selection, dispersal, drift and diversification across two spatial extents: 25 km3 and 1 km3. The outcomes of the multivariate analyses, null models and generalized linear models identified prospective source waters and distributional relationships of total and viable cell counts with fracture water sulfate and manganese. Random processes (dispersal, drift and diversification) explain close to 50% of the variance of the phylogenetic beta diversity among the component taxa. Selection associated with differential abundance of the 16S rRNA gene V4 region and spatial and environmental factors identified sulfate and organic carbon plus manganese and a spatial coefficient. Selection by differential abundance was not a major driver of community assembly; accounting for ~4% each of the total abundances linked to sulfate and manganese. At a spatial scale less than 1 km3, it may be possible to identify either greater significance for sulfate and manganese or to identify additional environmental factors linked to selection. Demonstrated metabolism included nitrate reduction (common across all sampling locations and at each sampling campaign) and sulfate reduction (observed at one sampling campaign). The distributions of total and viable cell counts correspond with the distributions of sulfate and manganese, respectively. The fracture water was a source of sulfate and manganese, but not a source of nitrate. A limited analysis of rock porewater identified sulfate and nitrogen compounds (ammonia, nitrite and nitrate) in parts per million concentrations, suggesting that the rock is a source of these compounds, and this finding warrants an assessment of rock weathering as a driver of selection at these sampling locations. Phylogenetic relationships across sampling locations showed that the component taxa were more closely related than expected by chance; this pattern suggests that, at the spatial scale of the analysis, competitive exclusion was not a driver of subsurface community assembly. Co-existence of close relatives may be biologically relevant—and thus be a sign of diversification—or this pattern may reflect the 16S rRNA gene copy number combined with intra-genomic heterogeneity greater than the 97% sequence similarity threshold for binning sequencing reads into organizational taxonomical units (OTUs). The distribution of genes for energy metabolism was uniform across all sampling locations. A metatranscriptome assessment would help differentiate between the genes present from the genes expressed. Testing for a wider range of demonstrated metabolic capabilities would support RNA-level gene expression analyses. Overall, applying the ecological framework of four main drivers of community assembly show that, at the spatial scale of the sampling, up to 50% of the variance among community dynamics reflect randomness. Approximately ~1% of the total abundance was linked to measured metabolism; at smaller spatial scales, ~8% of the total 16S rRNA gene abundance was linked to differential abundances across—potentially connected--sampling locations. By sampling at smaller spatial scales, therefore, it may be possible to discern additional metabolic and selective processes. These data will inform models for the performance and long-term safety of geological repositories.

No description available.

The MH-2 science drill hole, on Mountain Home Air Force Base, Idaho, was drilled in 2012 to a total depth 1821 m as part of Project Hotspot. It encountered flowing artesian thermal water at 1,745 m below ground surface. This signature of a potential blind high temperature geothermal resource indicates that further analyses are needed to characterize the resource. Whole rock core was recovered to a total depth of 1821 m below ground surface and a suite of wireline logs collected. In this thesis I describe the lithologies represented in the core, correlate these lithologies to outcrop analogs, and identify and characterize petrophysical properties observable within the wireline logs, which represent fine-scale variations in stratigraphy, composition and/or alteration. The lithologies in the core are a series of basalts, brecciated and altered basalt, basaltic sands, carbonate-rich muds, and siliciclastic sediments. Basalt flows with evidence of increasing influence of an aqueous environment with time typify the lower half of core, whereas the upper half represents a period of diminished volcanism, lacustrine depositional environment, and a catastrophic water overflow event. The top of the core represents a resurgence of basaltic volcanism in the area. An overprint of brecciation at depth, fracturing, and secondary mineralization records the history of the geothermal system. All the elements of a relatively shallow and potentially energy generating geothermal resource are present at the MH-2 well location. These new data from the MH-2 borehole contributes to evaluating a parallel geothermal risk assessment of the Snake River Plain. Play fairway analysis was implemented for perhaps the first time in a geothermal regime. The Snake River Plain was divided up into three distinct play types; the area surrounding the Mountain Home Air Force Base was systematically identified as prospective. A region where sedimentary and altered rocks may create a seal, and blind faults create porosity in deep basalts.

Drainage systems on cold-based glaciers are often thought to be simple systems that can be approximated from the supraglacial components of temperate glaciers. Most studies concerning cold-based glacier drainage systems have only considered one facet of the system, with little regard for how the system components interact. Studying each component independently of the whole system constrains our ability to model drainage system function and development. This in turn restricts our potential to predict how drainage systems of cold glaciers may respond to environmental change. The overarching aim of this thesis was to understand drainage system development of a cold-based glacier, and to assess whether our current understanding of supraglacial hydrological systems is consistent with the drainage systems that form on cold-based glaciers. This thesis evaluated the drainage system of the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica, during the 2004/05, 2005/06 and 2006/07 ablation seasons. The study incorporated field, laboratory and numerical analyses, which resulted in a deeper understanding of the spatial and temporal variability of meltwater generation, drainage pathways, water stores and bulk discharge from the glacier. The findings showed that melt variability was driven by sediment and topographic variations, and that water storage in the form of cryoconite holes, intergranular flow, supraglacial ponds and refreezing dictated meltwater transmission to the glacier outlet. These results indicated that the structure, function and variability of the drainage system were inherently more complex than previous studies on supraglacial drainage systems had suggested. These new insights were combined together to construct a new conceptual model of the drainage system structure of a cold-based glacier. However, before the conceptual model can be used to produce a numerical model of drainage system function or development on cold-based glaciers, several issues need to be addressed. These include: refined methods for quantifying meltwater generation in cold, arid environments; methods to measure water storage on and under the glacier surface; further understanding of the development of permeable ice; and a better technique to quantify cryoconite hole connectivity.