ABSTRACT. Use of climatic models to predict the El Niño/Southern Oscillation (ENSO) cycle coupled with decision support system tools can optimize management of the major crops grown in South America. AquaCrop model was applied in this paper based on field data from a soybean deficit irrigation trial in the northwestern region of Uruguay. The AquaCrop model was suitable for simulating the biomass and yield at harvest, as well as the soil water content of the soybean crop root zone, with an acceptable goodness of fit (Willmott aggregation index [IoA] > 0.80) and low estimation errors (NRMSE