Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

During the spring growing season, periods of drought can cause a significant reduction in dry bean yield in Brazil. Therefore, irrigation is applied to reduce the risks associated with the variability in weather conditions. The common irrigation system in Brazil is a center pivot system. Irrigation managers usually operate a center pivot irrigation system in such a way that it requires more than one day to complete the irrigation of an entire field. In general, crop model simulations assume that irrigation of an entire field is completed in one day. This article presents modification made in the CROPGRO simulation model to provide irrigation managers with decision support information that is equivalent to their local conditions. The modified model takes into account the number of days that a center pivot irrigation system requires to complete one revolution. Different management regimes for three different water capacity center pivot systems were evaluated for dry bean as a function of net return for the State of Parana, Brazil. The management regimes that were evaluated included the completion of the center pivot revolution in either one, two or three days. Six different irrigation thresholds were applied, ranging from 40 to 90% of the remaining available soil water content, and three different commodity prices were analyzed. The center pivot system that showed the highest net return was the system that applied 6 mm/day. The irrigation management regime that resulted in the highest net return was to irrigate the entire field in one day (the highest frequency possible), when the soil water content in the top 30 cm of the profile dropped below 70 or 80% of available soil water, depending on the commodity price. Future research is needed to evaluate different weather conditions and soil types to make these modifications in the CROPGRO simulation model more widely applicable.