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Nutritive value and ensiling characteristics of maize stover as influenced by hybrid maturity and generation, plant density and harvest date

1993; Elsevier BV; Volume: 41; Issue: 1 Linguagem: Inglês

10.1016/0377-8401(93)90094-z

1873-2216

Nancy A. Irlbeck, James R. Russell, Arnel R. Hallauer, D. R. Buxton,

Food composition and properties

Because genotype, hybrid generation (F1 vs. F2), plant density and harvest date of maize (Zea mays L.) may influence grain-to-stover ratio of the forage, the effects of these variables on composition and ensiling characteristics of maize stover were investigated. In each of two years, three maize hybrids (A632 × LH38, early-maturing; B73 × Mo17, medium-maturing; B73 × Pa91, late-maturing) were grown in three replications at plant densities of 4.9, 6.9 or 8.9 plants m−2. In Year 2, the F2 generation of the hybrids was grown under conditions similar to those for the F1 generation. Plants were harvested at physiological maturity and 28 days after physiological maturity. Grain and stover were separated for determination of the grain-to-stover ratio and stover yield. Stover was analyzed as either forage or silage prepared in polyethylene bags. The early-maturing hybrid had a higher grain-to-stover ratio, higher stover in vitro digestible dry matter (IVDDM) concentration and lower stover concentrations of acid detergent fiber (ADF) and acid detergent lignin (ADL) than the other hybrids. Plant density did not affect either grain-to-stover ratio or stover IVDDM concentration. Maize harvested 28 days post-physiological maturity had a higher grain-to-stover ratio, higher stover concentrations of neutral detergent fiber (NDF), ADF and ADL, and lower stover concentrations of IVDDM, crude protein and total nonstructural carbohydrates than maize harvested at physiological maturity. Silage produced from stover harvested at physiological maturity had a higher lactic acid concentration than when harvested 28 days after physiological maturity. F2 generation maize had a lower grain-to-stover ratio, lower stover ADF concentration and higher stover crude protein concentration than F1 generation maize. Stover IVDDM concentration from the F2 generation was higher than that from the F1 generation in unensiled forage, but lower than that from the F1 in silage. Although there were no differences in the proportions of ADF and ADL in the NDF of stover forages or silages from F1 generation maize, proportions of ADF and ADL in the NDF were greater in stover silages than in stover forages from F2 generation maize. Concentrations of ADF and ADL in stover forage and the concentrations of ADF, ADL and NDF in stover silage were significant (P < 0.10) variables in stepwise regressions predicting IVDDM concentration. These results imply that stover IVDDM concentration is primarily affected by differences in cell-wall concentration and composition that are unrelated to grain-to-stover ratio.