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Identifying and Evaluating a Suitable Index for Agricultural Drought Monitoring in the Texas High Plains
Author(s) -
Moorhead Jerry E.,
Gowda Prasanna H.,
Singh Vijay P.,
Porter Dana O.,
Marek Thomas H.,
Howell Terry A.,
Stewart B.A.
Publication year - 2015
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/jawr.12275
Subject(s) - evapotranspiration , agriculture , environmental science , crop , index (typography) , precipitation , farm water , hydrology (agriculture) , agricultural productivity , water resource management , agronomy , irrigation , geography , forestry , water conservation , ecology , meteorology , biology , geology , geotechnical engineering , archaeology , world wide web , computer science
Drought is a complex and highly destructive natural phenomenon that affects portions of the United States almost every year, and severe water deficiencies can often become catastrophic for agricultural production. Evapotranspiration ( ET ) by crops is an important component in the agricultural water budget; thus, it is advantageous to include ET in agricultural drought monitoring. The main objectives of this study were to (1) conduct a literature review of drought indices with a focus to identify a simple but simultaneously adequate drought index for monitoring agricultural drought in a semiarid region and (2) using the identified drought index method, develop and evaluate time series of that drought index for the Texas High Plains. Based on the literature review, the Standardized Precipitation‐Evapotranspiration Index ( SPEI ) was found to satisfy identified constraints for assessing agricultural drought. However, the SPEI was revised by replacing reference ET with potential crop ET to better represent actual water demand. Data from the Texas High Plains Evapotranspiration network was used to calculate SPEI s for the major irrigated crops. Trends and magnitudes of crop‐specific, time‐series SPEI s followed crop water demand patterns for summer crops. Such an observation suggests that a modified SPEI is an appropriate index to monitor agricultural drought for summer crops, but it was found to not account for soil water stored during the summer fallow period for winter wheat.