Date of this Version
Bosch-Rubia, Gustavo. "Land Use and Water and Soil Management Practices Impacts on Potential Groundwater Recharge in Loess Regions of South Central Nebraska" (2015). Biological Systems Engineering - Dissertations, Theses, and Student Research
Sustainability of agro-ecosystems must consider land use and water and soil management effects on groundwater recharge. Water flow beneath the plant root zone through the intermediate vadose zone determines potential groundwater recharge. Different land uses, water and soil management practices control deep percolation as a result of changes on evapotranspiration and infiltration. This study of the impact of surface activities on deep percolation was conducted at six locations across Nebraska: Two center-pivot irrigated no-till planting systems fields were compared with one tilled center-pivot irrigated field, a furrow irrigated field with multiple tillage treatments, an eco-fallow dryland farming system, and a native rangeland. Deep profiles of water content and nitrate-nitrogen data were collected from soil samples obtained using direct-push coring to 19+ m depths. Two methods were used to estimate potential groundwater recharge: Nitrate peak displacement method and Darcy’s Law with unit gradient assumption. Results indicate that groundwater recharge was affected by land use. Potential groundwater recharge of furrow irrigated fields>center pivot irrigated fields>dryland eco-fallow>native rangeland. Although furrow irrigation resulted in greater potential recharge, it is not necessarily better for the aquifer due to the larger amounts of water extracted from the aquifer for furrow irrigation compared to CP irrigation. While tillage practices did not cause differences in recharge under center pivot irrigated fields, tillage practices did have an impact in the furrow irrigated fields, especially at the upstream end of the furrows.
Advisor: Dean E Eisenhauer