Características agronômicas e bromatológicas de milho para silagem sob diferentes densidades populacionais

Abstract

Corn is considered the standard forage for dairy and meat producers worldwide, as it provides silages with the best quality, due to several agronomic and bromatological factors. Among the cultural management techniques, the planting density is one of the most important parameters, but it can affect the quality of the silage, since it affects the proportion between the parts of the plant: ear, stems and leaves, which also affects the chemical composition and fermentation. The objective of this work was to evaluate the agronomic and bromatological characteristics of corn hybrids from the company Helix Sementes, in the region of Alto Paranaíba - Minas Gerais, submitted to different population densities. Seven hybrids (BM 3069 PRO3, BM 3066 PRO3, HLX 2301 PRO3, HLSP 2201 PRO3, BM 953 PRO4, BM 3088 PRO4, SHS 7970 PRO3) from the company were evaluated, submitted to 4 population densities (55,000, 65,000, 75,000 and 85,000 plants ha-1) for agronomic characters and bromatological values. The agronomic traits evaluated were: plant height (PH), ear height (EH), disease scores (DE), lodged and broken plants (L+B), green mass productivity (GM) ha-1, dry matter productivity (DM) ha-1 and spike/plant ratio. The chemical values evaluated were: dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), total digestible nutrients (TDN), ether extract (EE) and starch. The GM and DM productivity values per ha-1 and plant height increased as plant populations became denser. No statistically significant differences were observed in bromatological values with population density, separately, however the hybrid x population density interaction was significant, showing that the alteration of bromatological values with population density depends on the hybrid. The hybrid BM 3069 PRO3 (H2) showed the highest yields of GM and DM ha-1 and the highest plant heights at a population density of 85,000 plants ha-1, without damage to bromatological values, in addition to showing better leaf health and low incidence of bedridden and broken plants, being the most suitable for forage planting in the Alto Paranaíba region, Minas Gerais.