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United States Department of Agriculture

Agricultural Research Service

Title: Calculating crop ET values when lysimeter data are not available.

item Marek, T
item Colaizzi, Paul
item Howell, Terry
item Porter, D

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2006
Publication Date: 8/9/2006
Citation: Marek, T., Colaizzi, P.D., Howell, T.A., Porter, D. 2006. Calculating crop ET values when lysimeter data are not available. 2006 North Plains Ag Day Proceedings, Amarillo Agricultural Research Center, August 9, 2006, Amarillo, Texas.

Interpretive Summary:

Technical Abstract: The Texas High Plains Evapotranspiration (TXHPET) network utilizes a heat unit-based approach (growing degree day concept) in the timing of various crop growth stages along with crop coefficients for computation of crop water use with the newly standardized ASCE/EWRI reference evapotranspiration (ET) equation. Mean crop coefficients of the TXHPET network are empirically derived from measurements using the large, monolithic lysimeters located at the USDA-ARS at Bushland, TX. Average regional crop growth stages are adjusted using multi-year, in-season, recorded data from irrigated producers through the Texas Cooperative Extension's Agri-Partner program. A comparison of the seasonal and crop stages of the TXHPET network as compared with the FAO-56 method, which utilizes date based timing for the crop growth stages, for the major crops of corn, grain sorghum and soybeans is presented. The North Plains Evapotranspiration network (NPET) has been in operation providing meteorological and crop water use (evapotranspiration or ET) data to producers for over 14 years. Recently, the NPET and South Plains ET (SPET) merged to form the Texas High Plains ET network (TXHPET). Each of the respective regional networks still remain but the merger allowed us to form a new network web site and database whereby the data could be queried and even plotted on the users computer screen via the Internet. The new TXHPET site recently received a blue ribbon award in the category of education tech transfer at the 2006 American Society of Agricultural and Biological Engineers International Meeting in Portland, OR. The site is focused toward Texas High Plains growers and includes access to virtually all the data compiled and computed daily from the TXHPET network stations. The primary objective of the TXHPET network is to compute crop water use data. The crop water use data disseminated by the network are estimates from the network weather stations but is considered to be some of the most accurate values in existence.

Last Modified: 06/25/2017
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