Crop growing periods and irrigation needs of corn crop at some stations in Northeast Brazil

Results of a climatological study of soil moisture under corn crop at six stations in the semiarid region of Northeast Brazil are reported in this paper. Daily values of available soil moisture during the wet season are evaluated using a six-zone versatile soil moisture budget (VSMB) model. A first order Markov chain model is applied to the daily soil moisture data. Soil moisture averages and probabilities are used to identify the optimum growing periods for corn crop at the stations, and the irrigation needs during these periods are evaluated. The effect of soil hydro physical properties in the VSMB model is discussed. The use of mean daily precipitation values in the model in place of actual precipitation data is briefly discussed.