The aim of this paper is to determine the water deficiency for soybean (Glycine Max) during two sowing periods, in Dourados, Mato Grosso do Sul, Brazil. The study is based on daily rainfall data and meteorological parameters, used to estimate the evapotranspiration. The reference evapotranspiration was estimated by the Penman-Monteith method. The meteorological data of 20 years, were collected at the Embrapa Meteorological Station, in Dourados. The soybean water deficiency was calculated through a daily sequential water balance and considered as the difference between the maximum crop evapotranspiration and the real evapotranspiration. The physical attributes of the soil were estimated from the retention curves of a Red Latosol. During most of the years, the November sown soybean presented larger water deficiency than the December sown soybean: the November soybean presented larger deficits from the second node stage to the beginning of the bloom, while in the December soybean, the larger water deficits occurred from the beginning of bloom to the beginning of grain formation. There was water deficiency in all soybean subperiods and every year for both the sowing periods.
Glycine Max; water balance; water deficit; evapotranspiration; effetive precipitation
