Characterization of climatic hazards for some crops has been carried out using simulation models, and for the dry bean crop (Phaseolus vulgaris L.) one that has been used is the CROPGRO-Dry Bean. Such model calibrated and tested for Santo Antônio de Goiás, Goiás State, Brazil, was used to detect relative bean yield losses imposed by the climate in that region. Simulations were performed using the climatological series (1978 to 1998), the soil physical, chemical and hydric characteristics (Oxisol), and the DSSAT 3.5 system seasonal module. Simulations were made to obtain the potential (Yp, without soil water deficit) and actual (Yr, soil water deficit dependent on rainfall) yields for the cultivar Carioca. Percent yield loss, defined as Q(%) = [1 - (Yr/Yp)].100, was calculated for each of the 36 sowing dates simulated along the year, for the 21 years evaluated, and expressed as relative distribution frequency. Results revealed Q > 50% for the "dry" season; on average Q = 34% for the "wet" season; and Q > 95% for the "winter" season. It is clear that supplementary irrigation was necessary in the first two sowing seasons, and during the entire crop cycle during the winter season.
common bean; CROPGRO - Dry Bean model; yield decrease
