Calibração do modelo AquaCrop e necessidades hídricas da cultura do tomateiro cultivada em condições tropicais.

Abstract

The main objective of this work was to calibrate the AquaCrop model for the tomato crop in order to make it applicable in the simulation of productivity in tropical semiarid regions and especially for the Agreste of Paraíba. In this research two field experiments were carried out in the study area, located in the city of Campina Grande-PB between the years 2016 (dry period) and 2017 (rainy season) using the "Shanty" variety. The experimental design was completely randomized, with 5 treatments that consisted of 100, 80, 60, 40 and 20% of replenishment of the water requirement of the crop with 4 replications each, totaling 20 experimental plots. The characteristics of the plant and its fruit were analyzed, trying to understand the behavior of growth and production in function of this variation. Evapotranspiration of the crop was also determined along with its coefficient. We used data obtained in the treatment of 100% replacement for calibration of the AquaCrop model and its validation was obtained by comparing the values found by the model with those observed in the field under conditions of water deficit. Among the several results found in the research, the variables such as weight, transverse diameter and longitudinal diameter of the tomato showed significant differences for the treatments in the two experiments. The recommended blade for irrigation was 100%, however, the results showed that the 80% replacement presented a good approximation of this recommended. Kc values found for the initial, development, intermediate, final and harvest stages were 0.40; 0.75; 1.11; 0.93 and 0.70, respectively. Finally, this proposal of validation of the AquaCrop model was satisfactory from the statistical point of view because it presented excellent and good results for the total biomass and productivity, presenting determination coefficients of 99% and 90%, respectively, confirming the capacity of the model to make good estimates of yields in situations of water deficit in tomato.