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Estimating Evaporation and Transpiration from a Row Crop during Incomplete Cover 1
Author(s) -
Tanner C. B.,
Jury W. A.
Publication year - 1976
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1976.00021962006800020007x
Subject(s) - lysimeter , transpiration , evapotranspiration , potential evaporation , mathematics , evaporation , environmental science , agronomy , horticulture , soil science , botany , physics , meteorology , biology , soil water , ecology , photosynthesis
In order to model the evapotranspiration (ET) from a crop with incomplete cover, the evaporation (E) is estimated separately from the transpiration (T) since E and T usually do not vary proportionately. Our objective was to develop and test an ET model based on the “potential” ET formula of Priestley and Taylor and ‘potential’ E and T estimates that are consistent with the potential ET estimate. When E is less than the potential E (the falling rate phase), it is estimated by two approaches based on E falling as t½; however, the model assumes transpiration is at the ‘potential’ rate. ET estimates during cover development of potato ( Solanum tuberosum L. ‘Russet Burbank’) for 2 years were compared with lysimeter measurements. The standard error of estimate varied from 0.40 to 0.94 mm/day depending on the method for estimating E. The estimate of cumulative ET for 4 weeks varied from the lysimeter a maximum of 1 cm in 9.7 cm ET.