Viabilidade técnica e econômica da produção de forragem do capim sudão irrigado por aspersão convencional

Abstract

Cultivated pastures represent the best alternative to supply the demand for nutrients and provide quality roughage to animals, increasing daily weight gain and improving the efficiency of the production system. To maintain forage quality in periods with irregular rainfall, supplementary irrigation is an alternative to ensure production, however, it is necessary to know the economic viability of the activity so that profits are maximized. The objective of the present study is to evaluate the biometric characteristics and the economic viability of Sudan grass irrigated by conventional sprinkling, under different irrigation depths, trying to define which scenario presents the highest profitability, under three cuts of uniformity (50, 80 and 110 days after sowing). The work was carried out in the municipality of Santa Maria, RS, sowing was carried out in November of the years 2015 and 2016. To verify the economic viability of conventional sprinkler irrigation, the efficiency of water use by the crop was determined, making it possible to determine the net revenues for each treatment. The forage supply was 4% of the animal live weight, being considered 300 kg animals, different average gains of 0.5, 1.0 and 1.5 kg animal-1 day-1 were simulated for the conversion of mass production drought in daily animal weight gain, considering the average value of the kilogram of meat paid to the producer R $ 6.50, to determine the gross income. To determine production costs, they were divided into fixed and variable, related and unrelated to irrigation. Conventional sprinkler irrigation proved to be viable in most of the scenarios tested, with the highest net revenue in the treatment with the irrigation depths with 100% of reference evapotranspiration in both years, with full water supplementation being recommended to obtain the greatest profitability.