Yield and Quality of Forage Maize as Influenced by Hybrid, Planting Date, and Plant Density
- J. S. Graybill,
- W. J. Cox and
- D. J. Otis
Although forage maize (Zea mays L.) is grown extensively on livestock operations, most management studies in the USA focus on grain production. Field studies were conducted in New York to evaluate dry matter (DM) yield and forage quality responses of commercial hybrids to planting dates and densities. Six hybrids were planted on 25 April, 9 May, and 23 May and thinned to 5.0, 6.5, and 8.0 plants m−2 in 1988 and 1989. A significant year ✕ planting date interaction was observed for DM yield because dry early-season conditions in 1988 negated the advantage of early planting in northern latitudes (13.4, 13.9, and 14.6 Mg ha−1 for planting dates 25 April, 9 May, and 23 May, respectively). When averaged across years, high plant densities increased DM yields (15.7,16.5, and 17.5 Mg ha−1 at 5.0, 6.5, and 8.0 plants m−2, respectively) with no significant effect on harvest index (524,523, and 526 g kg−1 at 5.0,6.5, and 8.0 plants m−2, respectively). A hybrid ✕ density interaction was observed for DM yield that suggests that some hybrids in this study performed better at higher densities. Plant density had little effect on acid detergent fiber (ADF) and neutral detergent fiber (NDF) concentrations indicating that forage quality can be maintained at high densities. Hybrids showed distinct variation for ADF (186-217 g kg−1), NDF (414-434 g kg−1), and crude protein (CP) (72-77 g kg−1) concentrations. The forage quality differences among hybrids may be of sufficient magnitude to be of value to the forage producer.
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