Potential of Sweet Sorghum Juice as a Source of Ethanol for Semi-arid Regions: Cultivars and Spacing Arrangement Effects

This research was carried out to evaluate the production and quality of sweet sorghum juice produced in Brazilian semi-arid region, identifying the best spatial arrangements and varieties for this goal. Two agricultural cycles (years 2015 and 2016) were carried out, in a sandy-loam Planosol under rainfed conditions. We assessed BRS 506 and SF-15 varieties, with row spacing (50, 60, 70 and 80 cm) and plant spacing (8, 12 and 16 cm) evaluated in a randomised complete block design with four replications in a triple factorial scheme. During the first cycle, BRS 506 presented mean values of 12.01 m3 ha−1, 23.86 kg ha−1, 16.88 °Brix, 140.02 g L−1 and 4,157.85 L ha−1 for juice yield and weight, total soluble solids content, total soluble carbohydrates and ethanol production. Even during the second cycle, under low rainfall, BRS 506 presented good juice production with proper quality, thus being drought tolerant. Our results showed that the smallest row spacing favoured the variables studied, and the sweet sorghum, cv. BRS 506, is indicated for ethanol production under Brazilian semi-arid conditions, at a spacing of 50 cm between rows and 8 cm between plants. We proved this crop is, therefore, a viable alternative for cultivation during sugar cane off-season in semi-arid regions.