ABSTRACT
MODELING THE OCCURRENCE OF DRY SPELLS AND THEIR IMPACT ON CROP YIELD
S.A.V. SOUSA Department of Rural Engineering, ESALQ/USP-FAPESP, Piracicaba, SP, Brazil J.A. FRIZZONE Department of Rural Engineering, ESALQ/USP, Piracicaba, SP, Brazil
Abstract A computational model, using Monte Carlo's Method, was development to simulate the occurrence of sequences of dry days during the cropping season and the consequent decrease in yield for a given crop. The simulation is based on series of frequency of sequence of dry days and evapotranspiration date. Valuation of the model was accomplished for corn production in the region of Piracicaba for two different crop periods: normal cropping season and cropping during the fall season ("safrinha"). Results show that in the normal cropping season the probability of substantial amount of lost is small. When cropping corn in Piracicaba during the fall season probabilities are higher of occurring substantial losses. For both cropping periods decreasing in yields was higher when dry days occurred during flowering stage. The stage of grain filling was the second most vulnerable crop stage to occurrence of dry days. Keywords: Dry spells, irrigation planning, modeling, Monte Carlo method.
