Keywords and Phrases
Agriculture; Evapotranspiration; Groundwater; NDWI; Remote sensing; Water stress
"Optimizing water use is a growing concern, especially in agricultural communities where water use is high. An important challenge in agricultural water optimization is knowing when and where crop water stress is occurring, particularly on large scales where in-situ measurements are no longer practical to obtain. In an effort to combat this challenge, this study utilizes remotely sensed evapotranspiration (ET) and Normalized Difference Water Index (NDWI) to evaluate the responses of integrated satellite datasets to water-stressed conditions over fields of irrigated corn, irrigated winter wheat, and rainfed winter wheat from 2007 to 2017 in southwestern Kansas. Using two different ET algorithms at various spatial resolutions, MOD16 and SSEBop, this research found that ET responses in water-stressed fields are lower in all three crop types with measurements of NDWI indicating lower crop water contents. Spatial resolution was found to be a critical factor in accurately separating the temporal signals of corn and winter wheat, as most MOD16 and SSEBop pixels contained a combination of various crops. After implementing additional filters that reduced the sample size only to fields with >90% pixel coverage over a single field of interest, the temporal trends better reflected trends found in previous studies and in Kansas crop growth manuals. Temporal trends of all three datasets suggest water stress can be quantified as an ET and NDWI deficit based on what is expected for each product. This study is a beginning step in determining quantitative criteria for “water stress” and how it appears in irrigated and rainfed crops through ET and NDWI datasets"--Abstract, page iii.
Smith, Ryan G.
Grote, Katherine R.
Borrok, David M.
Geosciences and Geological and Petroleum Engineering
M.S. in Geology and Geophysics
Missouri University of Science and Technology
ix, 48 pages
© 2021 Lindi Diane Oyler, All rights reserved.
Thesis - Open Access
Oyler, Lindi Diane, "Spatiotemporal observations of water stress in Kansas winter wheat and corn from remotely sensed evapotranspiration and NDWI" (2021). Masters Theses. 7979.