Dry Matter Recovery and Aerobic Stability of Maize Whole-Crop, Cob and Stover Silages—Harvest Date and Cultivar Effects
Forage maize (Zea mays L.) has the potential to produce high yields of excellent quality feed for ruminants. However, for regions with a cool overcast climate, improvements in maize silage production systems are required to reduce variation in yield and quality. Ensiling can reduce yield through dry matter (DM) losses and may alter feed quality. This study investigated the effects of harvest date on the DM recovery and aerobic stability of whole-crop, cob and stover silages produced from contrasting cultivars of maize. Six cultivars of forage maize, four of which were categorised as conventional (Tassilo, FAO 190; Beethoven, FAO 200; Andante FAO 200 and Nescio, FAO 230) and two categorised as high biomass (Atletico, FAO 280 and KXA 7211, FAO 260) were sown in 72 m2 plots under plastic mulch on 7 May 2008. Within each of three replicate blocks, harvest date (16 September, 7 October and 28 October) constituted the main plots and cultivar the sub plots within a split-plot design. Samples of whole crop, stover and cob from each plot were precision chopped and 6 kg of each were ensiled in laboratory silos for 130 days at 15 °C. After opening, sub-samples were subjected to chemical and microbial analyses, while aerobic stability and deterioration were estimated by measuring silage temperature during 8 days exposure to air. The rate of DM recovery of ensiled whole-crop, cob and stover was unaffected (P > 0.05) by harvest date or cultivar. No overall effects of harvest date or cultivar were observed on the aerobic stability or aerobic deterioration of whole-crop or stover silages. Cob silages harvested on 16 September underwent more (P < 0.05) aerobic deterioration than cob silages harvested at later dates. Cob silages produced from Nescio underwent less (P < 0.05) aerobic deterioration than for Tassilo, Beethoven and Andante.
KeywordsHarvest Date Maize Silage Plastic Mulch Silage Production Aerobic Stability
Funding for this study was provided under the National Development Plan through the Research Stimulus fund administered by the Department of Agriculture, Fisheries and Food (RSF 07 501). The provision of maize seed by Seed Technology Ltd., Ballymountain, Ferrybank, Waterford, Ireland, the input into crop production and ensilage by B. Weldon and Grange farm staff and the chemical analyses by Grange laboratory staff are acknowledged.
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