Avaliação de desempenho agronômico e nutricional do sorgo BRS 716 em diferentes espaçamentos e idades de corte no semiárido mineiro

Abstract

The BRS 716 biomass sorghum, a high-yield forage, is excellent choices for forage production in semiarid regions are scarce. This study aimed to evaluate the agronomic and nutritional characteristics of BRS 716 biomass sorghum managed at different planting spacings and cutting ages in a semiarid region of Brazil. Three spacings between planting lines (45, 70 and 90 cm; plots) and four of cutting ages (70, 100, 130 and 160 days; subplots) were evaluated following a randomized block design in a 3 x 4 split plot scheme, with eight blocks. The useful area of the parcel was 3 x15 m. The variation in soil fertility in the area was the blocking factor. There was interaction of planting spacing and cutting ages studied (P < 0,05) on plant height (P = 0,01), dry matter production (PMS; P < 0,01) and proportion of senescent material (P=0,01). The PMS (36,61t ha-1) verified at the age of 160 days and spacing of 90 cm was 41.40% higher than the PMS verified at the same age and in the spacing of 45 and 70 cm (average of 21.45 t ha-1). As cutting age increased, there was a reduction in crude protein content (P < 0,01), potential degradability (P < 0,01) and effective degradability (P < 0,01) of dry matter and increased non-fibrous carbohydrate content (P < 0,01), total digestible nutrients (P < 0,01) and the readily soluble fraction (P < 0,01) of dry matter. Considering the productive and nutritional characteristics of the BRS 716 biomass sorghum managed in the semiarid region, it is recommended that the spacing between planting lines be 90 cm and the cutting age 160 days after planting.