Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Subject: search.filters.subject.Hybrid Poplar

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    Hyperspectral Reflectance as an Indicator of Foliar Nutrient Levels in Hybrid Poplar Clone OP-367 Grown on Biosolid Amended Soil
    (2009) Griffeth, Tommy; Felton, Gary; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Trees of the genus Populus are fast growing trees that require considerable amounts of water and nutrients to meet physiological growth demands. The determination of correlations between hybrid poplar leaf spectral reflectance in the 325-1100 nm range, laboratory foliar analysis of leaf macronutrient and micronutrient concentrations, and leaf water potential datasets were analyzed using Full Cross-Validation and Test Set Models via the partial least squares (PLS) method of regression analysis. Based on an evaluation of the slope of the Predicted vs. Measured regression line, the root mean squared error (RMSE), and r-squared, the majority of the models constructed did not adequately model foliar concentrations from spectral data. However, the models for H, N, P, K, Cu and Al had values (slope of the Predicted vs. Measured regression line greater than 0.50 and r-squared values greater than 0.50 in at least one type of model) that warrant future study.
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    Utilizing Hybrid Poplar Trees to Phytoremediate Soils with Excess Phosphorus
    (2005-09-01) Neal, Amy; McIntosh, Marla S; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Phytoremediation, using plants to remove soil pollutants, has been suggested as a method to remove P from over-enriched soils. This research investigated the potential of utilizing hybrid poplar trees to remove excess P from soils associated with long-term poultry manure application. Hybrid poplar clones were planted in Snow Hill, MD, on three fields differing in previous poultry manure applications with Mehlich-3 soil-test P levels of 261, 478, and 982 mg P kg-1. During this two year study, soil P decreased on fields planted with hybrid poplar; the magnitude of the reduction was positively associated with initial soil-test P. Plant tissue P concentrations increased with soil P concentration. However, factors other than plant uptake were hypothesized to contribute to the soil-test P reductions. Results suggest that hybrid poplars have the potential to phytoremediate soils with excess P but that soil chemistry also impacts the fate of available P in the soil.