Evaluation of the crop coefficients for tomato crop grown in a Mediterranean climate.
Effective improvement in crop coefficient (Kc) estimates is particularly important for mid-season Kc values, because mid-season Kc refers to the peak Kc values and relies on the period of growing season that is usually the most relevant for irrigation and the most sensitive to water stress, thus when accurate scheduling should be applied. The relationship between crop coefficient and growing parameters (temperature) was investigated for tomato (cv. Dracula) on the basis of experimental data obtained from the experimental station of Bari University and CNR-Bari "E. Pantenelli", located in Policoro (Southern Italy). A strong relationship was observed between crop coefficient and temperature suggesting good potential for use of a growing degree days approach for estimating crop evapotranspiration. The overall results for tomato grown under semi-arid conditions, indicates that the initial Kc can be neglected and that the Kc and crop evapotranspiration (ET c_model) can be modelled through the three-stage growing cycle and linear relationship between Kc and cumulative growing degree days. Furthermore, this work has confirmed that peak Kc estimation can be improved by applying the corrections for relative humidity, wind speed and plant height as suggested in FAO 56.