| Popis: |
The Penman-Monteith equation has been used to describe the transpiration of greenhouse crops; however, it generally requires re-parameterization for each dataset, restricting the robustness of the equation for predictive purposes. This paper applies the equation to a transpiration dataset for greenhouse tomatoes collected over a period of three years. The parameters needed were taken from directly from the literature. The resulting model predicted transpiration surprisingly well, but the error dependent upon leaf area index. A significant improvement in performance was obtained by making the vapor pressure deficit term dependent on a declining function of leaf area index and by fixing the internal resistance of the canopy as a constant. The resulting model predicted transpiration within a mean error of 3.64% over the entire dataset and the errors were much more consistent across canopy density, vapor pressure deficit and ventilation flow rate than with the original model. |
