Spacing Arrangements and Environmental Factors Influence Biomass Production of Sweet Sorghum Cultivars Grown in Semi-arid Regions

Background and Objective: High biomass production of sweet sorghum [Sorghum bicolor (L.) Moench] may be obtained by using cultivars adapted to a determined environment and by adopting the most appropriated spacing arrangement.The aim of this study was to evaluated the effects of different spatial arrangements on the biomass productivity of two sweet sorghum varieties in the Brazilian semi-arid region.Materials and Methods: Two agricultural cycles (2015 and 2016) were carried out under rainfed conditions.The varieties used were BRS 506 and SF 15 and spacing between the rows (50, 60, 70 and 80 cm) and between plants (8, 12 and 16 cm) were evaluated in a randomized complete block design with four replications and a triple factorial scheme.The fresh and dry matter of the leaves, panicle and stalk were evaluated.Dry matter mass was determined by summing the mass of the dry matter of all the parts.Results: The values obtained with the BRS 506 variety in the first cycle were higher than those observed in the SF 15 variety.Results showed that the BRS 506 variety had the highest growth under appropriated rainfall conditions (1st cycle), while the SF 15 showed a small improvement in growth during the second cycle, which was characterized by a long and severe drought.In this context, the observed superiority for BRS 506 from one cycle to the next was 233.4%.The closer spacings between the rows and between plants provided higher average biomass due to the greater amount of material per area.Conclusion: The BRS 506 variety is recommended for biomass production in the semiarid at a planting density of 250,000 plants haG 1 .