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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Agricultural and Biosystems Engineering

First Advisor

Christopher H. Hay


Cover cropping is a popular agriculture practice that provides many benefits to the soil and subsequent cash crops. However, eastern South Dakota lies in a transitional climatic zone between the subhumid climate to the east and the semiarid climate to the west, an area susceptible to both excess and shortage of water. This research contains two parts: (1) estimation of actual evapotranspiration (ETa) using the Bowen-ratio method to calculate crop coefficient curves for a field in eastern South Dakota which in 2011 contained spring wheat followed by a cover crop and in 2012 contained field corn, and (2) utilization of Landsat imagery and the image processing model METRIC (Mapping Evapotranspiration at high Resolution using Internalized Calibration) to estimate lateseason, post-harvest ETa from fields with and without a cover crop planted after spring wheat for the 2011 growing season. Using the Bowen-ratio method, a crop coefficient curve (KλE) was developed and compared to the dual-crop coefficient method (Kc). The results show—with 95% confidence—that for the spring wheat crop, KλE was significantly greater than Kc, for the cover crop KλE was significantly less than Kc, and for the field corn crop KλE was again significantly less than Kc. Using METRIC to extrapolate the point-source data for application across eastern South Dakota, a crop coefficient curve was developed based on the METRIC methodologies and was used to compare estimated ETa for three fields that used cover crops after a spring wheat crop and three fields that did not use a cover crop after a spring wheat crop. METRIC-derived values were found to compare favorably with the estimated ETa found using the Bowenratio method (ETλE), with a difference in total estimated ETa for the cover crop season of 7%.

Library of Congress Subject Headings

Cropping systems -- South Dakota.
Crops and Water -- South Dakota.
Cover crops -- South Dakota.


Includes bibliographical references.



Number of Pages



South Dakota State University


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