Date of Award
12-10-2015
Document Type
Dissertation
Degree Name
Environmental Sciences, Ph.D.
First Advisor
Jerry Farris
Committee Members
Hashim Ali; Mathew Moore; Rich Grippo; Seo-eun Choi; Steve Green
Call Number
LD 251 .A566d 2015 I63
Abstract
Agricultural drainage systems are considered innovative best management practices (BMP) capable of many ecological functions, including flood control, edge of field nutrient filtration, as well as habitat for wildlife. Being an integral part of the production landscape and needing no additional cost for establishment, their use has been promoted in agriculture as cost effective BMPs that can be voluntarily adopted by farmers. The current study evaluated the effectiveness of drainage ditches (as influenced by their landscape properties) in mitigating edge-of-field nutrient runoff and measured additional ecosystem services rendered by these systems. Two experimental drainage types [conventional and controlled (with weirs) ditches] with well-established vegetation were utilized for the study. Two of each treatment types were mowed to assess the influence of vegetation maintenance. Results indicated weirs in ditches played a vital role in enhancing ditch capacity for phosphorus (P) sorption because inundation created by weirs stimulates a reduction reaction that provides increased surface areas for P sorption. A lack of significant differences observed in nutrient reduction between mowed and unmowed ditches demonstrated occasional ditch mowing would not undermine the nutrient mitigation capacity of vegetated drainage ditches. Ecosystem metabolism was monitored within ditch treatments to assess additional ecological functions and to establish a cost effective platform for assessing metabolism in adjacent large scale aquatic ecosystems draining agricultural catchments. Results indicated vegetation clippings left in ditches after mowing, in addition to impoundment created by weirs, influenced community respiration by stimulating additional heterotrophic microbial respiration in these systems. Likewise, the additional hydrological benefit (of soil inundation) gained from weir installation supported increased vegetation density, hence a significantly higher gross primary production was observed in ditches with weirs than in those without weirs. Results were comparable with large scale whole stream metabolism measurements in previously reported studies, signifying monitoring metabolism in these systems at lower scales could be a cost effective means of assessing whole stream metabolism of contiguous large scale streams draining agricultural catchments. Lastly, the potential for carbon sequestration was investigated within ditch treatments. Results demonstrated ditch treatments can be considered as carbon sinks given that a high carbon pool was measured in all treatments, although no significant difference was observed in the carbon pool between ditches with and without weirs. The current study demonstrated modifying vegetated agricultural ditches by installing weirs will enhance nutrient mitigation and other ecological functions in these systems. Collectively, the study further demonstrated the effectiveness of agricultural ditches in mitigating edge-of-field nutrient runoff and their capability of performing additional ecosystems services.
Rights Management
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Iseyemi, Oluwayinka Omolara, "Effectiveness Of Agricultural Drainage Systems on Contaminant Mitigation: The Influence of Landscape Properties" (2015). Student Theses and Dissertations. 686.
https://arch.astate.edu/all-etd/686
