Ensilagem de sorgo cultivado em diferentes espaçamentos e densidades de semeadura

Abstract

Sorghum tends to morphologically alter when submitted to different cultivation conditions, and a good amount of green matter and grains is expected for ensiling. The objective of this study was to evaluate the agronomic and productivity characteristics, dry matter losses in the silage and the bromatological composition of forage and sorghum silage grown in different arrangements. The study was conducted at the Federal Institute of Education, Science and Technology of Rondônia, Campus Colorado do Oeste. The experimental design was a randomized block design, with four replications. The treatments were arranged in a subdivided plot scheme: the plot corresponded to three spacing’s between rows (0.45, 0.60 and 0.75 meters); and the subplot corresponded to four sowing densities (105,000, 120,000, 135,000 and 150,000 plants ha-1 ). The agronomic and yield characteristics of sorghum were evaluated; losses of dry matter in silage and dry matter recovery; and the fermentative and bromatological characteristics of forage and silage. The sorghum plants presented higher plant height (ALT), green mass (PMV) and dry mass (PMS) productivity with density increase (P<0.05). For the stem diameter variable (DIAM), we observed the isolated effect of spacing and density, with reduction of thickness under high density conditions and reduction of spacing. It was not observed influence of the factors (P>0.05) for the morphological components of the plant and losses of DM in silage. The mineral matter (MM) contents of the forage and silage have an effect of the combination of spacing and density. In the silage, larger spacing’s promoted high dry matter (DM) content. For the crude protein (CP) of the silage, high percentages were obtained in smaller spacing and higher density. Cultivation of sorghum under densified conditions is indicated, given the positive performance in productivity and bromatological composition.