Irrigation is a technique with high potential to increase crop yield, however, it is necessary to evaluate the energetic efficiency of irrigated agriculture. So, this study aimed at evaluating the irrigation impact on grain yield and energetic balance of two castor bean cultivars submitted to supplementary drip irrigation with different water depths. The experiment was conducted in a clayey Dystrophic Purple Latosol, in Dourados, Mato Grosso do Sul State, Brazil. The experimental design was randomized blocks in a bifactorial scheme, with five water depths (0%, 25%, 50%, 100% and 150% of evapotranspiration for localized irrigation) and two castor bean cultivars (IAC 2028 and IAC 80), with four replications. The irrigation interval was of up to two irrigations per week, except for the days when rainfall occurred. Crop yield and the relation energy produced in the form of grains/energy used in cultivation were evaluated. It was concluded that the supplementary irrigation increased yield, as well as the relationship between energy production and consumption.
Ricinus communis L.; energetic balance; supplementary irrigation
