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Journal of Agricultural Science and Technology 13, 2 (2011) 209-221

Derived crop coefficients for winter wheat using different reference evpotranspiration estimates methods

S. Er-Raki (  Auteur correspondant ) 1, A. Chehbouni 2, J. Ezzahar 3, S. Khabba 3, E. K. Lakhal 3, B. Duchemin 2

(2011)

This paper reports the results of using three empirical methods (Makkink, Priestley-Taylor and Hargreaves) for estimating the reference evapotranspiration (ET0) in the semi-arid region of Tensift Al Haouz, Marrakech (center of Morocco). The Penman-Monteith equation, standardized by the Food and Agriculture Organization (FAO-PM), is used to evaluate the three empirical methods. The obtained ET0 data were used to estimate crop water requirement (ET) of winter wheat using the crop coefficient (K-c) approach and results were compared with ET measured by the Eddy Covariance technique. The result showed that using the original empirical coefficients a, alpha and C-m in Hargreaves, Priestley-Taylor and Makkink equations, respectively, the Hargreaves method agreed fairly well with FAO-PM method at the test site. Conversely, the Priestley-Taylor and Makkink methods underestimate the ET by about 20 and 18 %. After adjustment of the original values of two parameters alpha and C-m coefficients in Priestley-Taylor and Makkink equations, the underestimation of ET was reduced to 9% and 4% for the Priestley Taylor and Makkink methods, respectively, which led to an improvement of 55% and 76% of the obtained values compared with the original values.

1 :	Université Cadi Ayyad, Marrakech
	Université Cadi Ayyad, Marrakech
2 :	Centre d'études spatiales de la biosphère (CESBIO)
	CNRS : UMR5126 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III
3 :	Faculté des Sciences SEMLALIA (FSSM)
	Université Cadi Ayyad (Marrakech, Maroc)

domaine

:

Sciences du Vivant/Ecologie, Environnement/Ecosystèmes Sciences du Vivant/Sciences agricoles/Agronomie

mots-clés : Crop water requirement – Eddy covariance – Empirical method – Semi-arid – Environment

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Contributeur : Dominique Bruel <>

Soumis le : Mardi 24 Avril 2012, 17:09:38

Dernière modification le : Jeudi 3 Mai 2012, 10:46:51