Yield, Nutritional Composition, and In Vitro Ruminal Digestibility of Conventional and Brown Midrib (BMR) Corn for Silage as Affected by Planting Population and Harvest Maturity

Abstract

The objective of this study was to evaluate the effects of corn-planting population, using two conventional (Conv) and two brown-midrib (BMR) hybrids, and maturity stage at harvest on forage dry-matter (DM) yield, silage quality, and in-vitro fiber digestibility. The study was conducted in two fields with contrasting production potential, where both corn hybrids were planted at a theoretical planting population of 59,000, 79,000, and 99,000 seeds/ha. Corn was harvested at the early-dent (early) or 2/3 milk-line (late) maturity stage. An interaction between planting population and field existed for biomass yield. We observed a consistent increase in forage yield with increased planting population only in the field of higher production potential. Corn hybrids that contained the BMR trait did not penalize yield but had a consistently higher digestibility of neutral detergent fiber (aNDFom) compared to conventional hybrids. Except for starch concentration, no interaction existed between planting population and maturity for forage yield, fiber digestibility, and nutritional composition. A response to increasing planting population on starch concentration was observed only when corn was harvested at the L = late maturity stage. In conclusion, increasing corn-planting population may increase forage yield, but such an effect may depend on the soil’s growing potential. In addition, planting population had a negligible effect on the nutritional composition and fiber digestibility of corn silage and was minimally affected by the maturity stage at harvest.