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Defining and Using Reference Evapotranspiration

Hargreaves, George H.·1994·Journal of Irrigation and Drainage Engineering
DOI 10.1061/(asce)0733-9437(1994)120:6(1132

Abstract

Values of reference evapotranspiration (ET0) are used with crop coefficients (KC) for many aspects of irrigation and water resources planning and management. More than a score of methods are used for estimating ET0. Estimated values vary widely due to the lack of standardization of the reference. Evaporation (ET) measured by lysimeters of various grasses and/or alfalfas has been used as the standard for developing estimating equations. Due to variation in the references used, some international organizations now wish to promote the use of a single equation or method to avoid the confusion caused by the current diversity. Different versions of the Penman combination equation have been proposed. The Research Center for the European Community and the ASCE Committee on Irrigation Requirements have evaluated various equations for estimating ET0. Due to its simplicity and the accuracy of estimates, the 1985 Hargreaves et al. equation is recommended for general use. ET0 is used in irrigation planning, design, and scheduling and for other water adequacy studies.

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  1. 10.1061/(ASCE)0733-9437(1985)111:3(265) · doi:10.1061/(asce)0733-9437(1985)111:3(265 · Paper page

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Metadata

Authors
Hargreaves, G. H.
Venue
Journal of Irrigation and Drainage Engineering
Published
1994-11
Volume
120
Issue
6
Pages
1132-1139
ISSN
  • 0733-9437 (ISSN-L)
  • 1943-4774
DOI
10.1061/(asce)0733-9437(1994)120:6(1132
OpenAlex
W1966145422
Cited by
601
References
0
FWCI
2.86
Type
journal article
Language
en
Open access
closed

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CoChat. (2026). Citation check: Defining and Using Reference Evapotranspiration. https://app.cochat.ai/papers/10.1061/(asce)0733-9437(1994)120:6(1132
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Hargreaves, G. H. (1994). Defining and Using Reference Evapotranspiration. Journal of Irrigation and Drainage Engineering. https://doi.org/10.1061/(asce)0733-9437(1994)120%3A6(1132

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