| heal.abstract |
Estimation of the water requirements of a crop (expressed by actual evapotranspiration, ET) grown in a Mediterranean type of climate is attempted, by taking into account the parameters and mostly soil moisture (θ) affecting the bulk stomatal resistance of the canopy (rc). In estimating r as a function of θ (rc=c θs/ θ), the critical soil water depletion fraction, c, of the maximum available to plants soil moisture (θs), below which ET cstarts deviating from its maximum value, is proposed to be calculated by a simple polynomial equation, originated from Deanmead and Shaw' s (1962) data. This equation requires knowledge of simply the evaporative demand of the atmosphere (ETmax). Meteorological and biometric observations as well as soil moisture measurements during the whole growing season of a maize crop in the Central Greece were used to test reliability of the proposed relation between crop establishment and maturity. A degree of reliability is provided by the lack of significant difference between cumulative ETcbased on soil moisture profiles, and ETcestimations, based on the Shuttleworth and Wallace's (1985) equation. © ISHS. |
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