Economic Viability of Conventional Sprinkler Irrigation in Sudan Grass Production for Beef Cattle

Abstract

The supplementary irrigation is an alternative to ensure forage production and quality in periods with irregular rainfall, however, is necessary to know the irrigation economic viability in order to maximize profits. The study was performed in Santa Maria, Rio Grande do Sul State in southern Brazil, during 2015/2016 and 2016/2017 agricultural years, aiming to evaluate the sudan grass economic viability under different irrigation depths, in order to define which irrigation depth (0, 25, 50, 75, 100 and 125% of the reference evapotranspiration-ETo) has the highest net revenue. Forage production functions were generated and allowed to establish the carrying capacity and production costs related to each applied irrigation depth. The forage supply was 4% of the liveweight, animals with 300 kg were considered, and average daily liveweight (LW) gains of 0.5, 1.0 and 1.5 kg LW day^-1 were simulated for the conversion of dry mass production in liveweight gain per hectare. Gross revenue was determined considering the price of R$ 6.50 per kilogram of liveweight. The production costs were divided into fixed and variable, related and not related to irrigation. The conventional sprinkler irrigation was economically viable for the sudan grass cultivation for beef cattle production, with the highest net revenue for the irrigation depth of 100% of ETo, in both years. However, the animals feed conversion is the determinant factor in net revenue because it represents the greatest profits variation source.