Dissertation/Thesis Abstract

Redox and soil manipulation effects on ditch soil phosphorus processing
by Ruppert, David Emmanuel, Ph.D., University of Maryland, College Park, 2012, 211; 3543417
Abstract (Summary)

Ditches increase the connectivity of landscapes to open water systems, potentially facilitating the degradation of downstream waterways. A treatment and an observational experiment were conducted to identify processes behind phosphorus (P) cycling in ditch soils. If the ditch had not undergone recent dredging soils were observed in the treatment experiment to release P to surface water whether the soil system was iron (Fe)-oxidizing or Fe-reducing. Also in the treatment experiment, Fe was released to surface water in appreciable amounts only if the soil system was Fe-reducing. From the observational experiment P release due to mineralization was inferred due to a positive trend with temperature. Also in the observational experiment Fe-reducing conditions were weakly correlated with diminished P concentrations in the ditch water. It was inferred that emergent Fe(II) released from within the soil through reductive dissolution captures P from ditch surface water upon oxidation. In the treatment experiment dredging and saturated conditions resulted in similar effluent P concentrations as drained soils that were undredged. This may explain a lack of dredging effect that was observed in the field.

Indexing (document details)
Advisor: Needelman, Brian
Commitee: Coale, Frank J., James, Bruce R., Lamp, William O., Rabenhorst, Martin C.
School: University of Maryland, College Park
Department: Natural Resource Sciences
School Location: United States -- Maryland
Source: DAI-B 74/03(E), Dissertation Abstracts International
Subjects: Biogeochemistry, Soil sciences, Environmental science
Keywords: Ditch, Dredging, Iron, Phosphorus, Redox, Soil
Publication Number: 3543417
ISBN: 978-1-267-72209-6
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