Consumo hídrico e calibração/validação do modelo AquaCrop para a cultura do feijão caupi cultivado no semiárido do nordeste do Brasil.

Abstract

The main goal of this work was to calibrate the AquaCrop model for cowpea bean in order to make it applicable in the simulation of productivity in tropical semi-arid regions and especially in the Northeast region of Brazil. In this research two field experiments were carried out in the study area, located in Campina Grande - PB from April to June 2018 (rainy period) and from September to November (dry period) using the bean ‘Vigna unguiculata ( L.) Walp’. The experimental design was completely randomized, with 5 treatments that consisted of 100, 80, 60, 40 and 20% of replenishment of the water required for the crop with 2 replicates each, totaling 10 experimental plots. The characteristics of the plant and its grain were analyzed, seeking to understand the behavior of growth and production as a function of this variation. Evapotranspiration of the crop was also determined along with its coefficient. The DAPa that was used, was obtained in the treatment of 100% replacement for calibration of the AquaCrop model and its valiDAPion 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 and diameter of the bean tree showed significant differences for the treatments in the two experiments. The recommended blade for irrigation was 100% and the results showed that the 20% replacement is not sufficient for the survival of the crop during the dry period in the region. The Kc values found were 0.85; 1.1; 1,2 and 1,0 for the initial, growth, reproductive and final stages, respectively. Finally, this proposal of valiDAPion of the AquaCrop model was satisfactory from the statistical point of view because it presented excellent results for the total biomass and productivity, confirming the capacity of the model to make good estimates of productivity in situations of water deficit in the bean tree.