Viabilidade da irrigação suplementar do feijoeiro na época das águas

Abstract

The study aimed to quantify the economic return provided by irrigation of common beans at rainfed season. Common bean yield was simulated for 30 growing seasons using the DSSAT-Cropgro-Dry bean model for the cultivar Pérola. The yield simulations considered sowing dates from November 1st to January 1st, and four water managements: rainfed and irrigation starting at 70%, 50% and 30% of the total soil water available. The irrigation at 70%, 50% and 30% of total soil water available increased yield, from 26.7% to 41.4%, from 5.5% to 14.5%, and from 0.4% to 2.4% in relation to the rainfed system. The average demand of 53 mm cycle-1 was required by the management 70% of total soil water available and19 mm cycle-1 for the 50% of total soil water available. The delay on sowing date after November 1st decreased the yield. A minimum sales price ranging from R$1.85 to R$2.83 per kg is required, according to the water management and the sowing date, for an internal return rate higher than 12%. Irrigation at 70% of total soil water available provides a similar or better economic index and a higher yield than the rainfed system.