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A knowledge of amounts and rates of evapotranspiration is necessary for the prudent allocation of water re sources within a region. This information is used in the design of diversion, storage, and distributional facilities of an irrigation system and provides a sound basis upon which to recommend efficient water application practices. Direct determination of evapotranspiration is laborious and time consuming, consequently numerous methods have been developed to estimate water requirements for areas in which evapotranspiration data are not available. These methods vary widely in their sophistication but all are based on one or more than one meteorological variable. Several formulas were considered by Laycock (7) in delineating the patterns of drought and moisture surplus in the Prairie Provinces. Underhill (12), in reporting to the Prairie Provinces Water Board also considered formulas and recommended that for the present the Blaney-Criddle method (2) be adopted as the basis for calculating crop water requirements. In this paper monthly evapotranspiration values for alfalfa at Vauxhall, Alberta, as measured by the gravimetric method on a plot basis are correlated with values as estimated by converting evaporation measurements and by three of the more common empirical formulas.
a comparison of measured and calculated evapotranspiration for alfalfa in southern alberta
Hobbs, E. H. and K. K. Krogman 1966. A COMPARISON OF MEASURED AND CALCULATED EVAPOTRANSPIRATION FOR ALFALFA in SouthERN Alberta. Canadian Agricultural Engineering 8(1):9-10.
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