|MAREK, THOMAS - TEXAS AGRILIFE RESEARCH|
|PORTER, DANA - TEXAS AGRILIFE EXTENSION|
|SINGH, VIJAY - TEXAS A&M UNIVERSITY|
|STEWART, B.A. - WEST TEXAS A & M UNIVERSITY|
Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/2013
Publication Date: 1/9/2014
Citation: Moorhead, J.E., Gowda, P., Marek, T.H., Porter, D.O., Howell, T.A., Singh, V.P., Stewart, B. 2014. Use of crop-specific drought indices for determining irrigation demand in the Texas High Plains. Applied Engineering in Agriculture. 29(6):905-916.
Interpretive Summary: Groundwater districts in the Texas High Plains require information on irrigation demand for groundwater management. Currently, estimating irrigation water demand is a time consuming process as it requires a lot of information and knowledge. Numerous drought indices use evapotranspiration (ET) or crop water use, and are simple to calculate. In this study, we evaluated statistical relationships between irrigation demand, and a simple crop-specific drought index that requires ET as an input. Results indicated that the statistical relationship between irrigation demand, and the crop-specific drought index provides a relatively simple tool to estimate irrigation demand at a county or regional level for groundwater management purposes.
Technical Abstract: Drought is a highly destructive natural phenomenon that affects portions of the U.S. almost every year. Severe water deficiencies can become catastrophic for agriculture and crop yields. Evapotranspiration (ET) is an important component in the agricultural water budget; thus, it is strongly preferred to include ET in agricultural drought monitoring. Consequently, the Standardized Precipitation-Evapotranspiration Index (SPEI) was recently introduced to monitor agricultural drought. In this study, statistical relationships between crop-specific monthly SPEI and corresponding irrigation demand were developed using Texas High Plains ET (TXHPET) network data, and evaluated for determining their usefulness in groundwater management within the Texas High Plains. Results indicate that the statistical relationship between irrigation demand and SPEI provides a relatively simple tool to estimate irrigation demand at a county or regional level for groundwater management purposes.