Resumo

CHATERLAN DURRUTHY, Yoima et al. Determining of Crop Coefficients for Horticultural Crops in Cuba through Field Experiments and Water Balance Simulation . Rev Cie Téc Agr [online]. 2010, vol.19, n.1, pp. 90-95. ISSN 2071-0054.

Proper management of irrigation water provides an optimal balance. With this objective the water balance simulation model ISAREG was calibrated and validated for micro-sprinkler irrigated sweet pepper, garlic, onion, cabbage and carrots, using field observations performed in the Irrigation Station of Alquízar, south of La Havana. Model calibration and validation were performed using two independent data sets for each crop. The calibration referred to the crop coefficients (K_c) and the soil water depletion factor for no stress (p) and to the soil hydraulic properties of a Red Ferralitic compacted soil. The calibration procedure consisted of adjusting first the soil properties and then, through an iterative procedure, to determine the K_c and p values that minimize the differences between observed and simulated soil water content along the crop season. The model validation was performed using the calibrated K_c and p with a different climate and crop data sets. The following indicators of goodness of fitting were used to assess model calibration and validation: regression coefficient forced to the origin (b), determination coefficient (R²), root mean square error (RMSE) and average absolute error (AAE). Results show a good agreement between field observations and model predictions, with b close to 1,0; R² ranging 0,84-0,95 for the calibration and 0,78-0,90 for the validation for all the five crops. The RMSE and AAE are small. RMSE ranged 0,97-2,08 mm for the calibration and 1,07 to 2,82 mm for the validation. The K_c and p values are in the range suggested in FAO 56. Results allow to further use the ISAREG model to define alternative irrigation schedules and to generate those that may provide for improved water productivity in Cuba.

Palavras-chave : good irrigation; calibrated; validated; vegetables.