ESTIMATED CROP COEFFICIENT (Kc) BEAN IN ILHA SOLTEIRA, SP

Abstract

Bean plants grown in almost all regions of Brazil, have irrigation as an essential technique when seeding is performed in the winter, so the crop coefficient (Kc) to be used for irrigation management can be obtained by means of an adjusted model through distribution versus time their average values. The purpose of this study is to determine Kc values in a protected environment and compare two water replacement intervals in Ilha Solteira region, SP. The experiment conducted in pots; treatments consisted of two different water replacement intervals with four replications. The crop evapotranspiration (ETc) was determined by the difference between the daily weighing of the pots, the reference evapotranspiration (ETo) was estimated by the Penman-Monteith method, and the Kc was determined by the ratio between ETc and ETo. Kc values were presented different at different stages of culture, they differed between treatments and presented characteristic curve of Kc. We conclude that treatment without daily replacement of water showed higher precision, accuracy and tendency when compared to treatment with daily addition of water, and the Kc values differ from those proposed by Doorenbos and Kassam emphasizing the need for determination of regional Kc values.