|Jung, Hans Joachim|
Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2005
Publication Date: 1/2/2006
Citation: Sheaffer, C.C., Halgerson, J.L., Jung, H.G. 2006. Hybrid and N fertilization affect corn silage yield and quality. Journal of Agronomy and Crop Science. 192:1-6. Interpretive Summary: Corn silage is among the most important forage crop grown for feeding dairy cows. The nutritional quality of corn silage is governed by the amount of starch from grain and fiber from the stover. Digestibility of the stover fiber fraction also contributes to the feeding value of corn silage. Special-purpose corn hybrids have been developed in the attempt to improve the feeding value of corn silage. The response in yield and nutritional quality of these special-purpose corn hybrids to nitrogen fertilization has not been adequately described. Two brown midrib hybrids (more digestible fiber) and one leafy hybrid (more digestible fiber and softer starch) were compared to a conventional corn hybrid at four nitrogen fertilization rates, from 0 to 200 lb per acre, at two locations in Minnesota. Increasing nitrogen fertilizer levels resulted in improved yields of corn silage from all hybrids, but rate of nitrogen fertilizer used did not impact nutritional quality (starch, fiber, or digestibility) of the different hybrids. Farmers can make decisions on amount of nitrogen fertilizer to use based on yield potential of the hybrids they grow without worrying about affecting silage quality for special-purpose corn hybrids.
Technical Abstract: Corn hybrids with improved forage quality have been developed, but the effect of N fertilization on their yield and quality is unknown. We determined the effect of N fertilization on DM yield, predicted milk yield, and forage quality of fresh (green chopped) and ensiled forage of two brown mid-rib (BMR) hybrids, a leafy hybrid, and a conventional silage hybrid. Increasing N rates from 0 to 200 lb per acre increased corn grain, stover, and whole plant DM yield and milk yield. The forage yield and quality response to N was similar for all hybrids. Nitrogen fertilization increased forage CP concentration but had little effect on other forage quality components. Brown midrib hybrids, F377 and F657, had the lowest grain, stover, and whole plant yield but had the highest digestibility and milk yield per ton of forage. Milk yield per acre was similar for the BMR, leafy, and conventional hybrids. Ensiling reduced starch concentration, but effects on other variables were less consistent. Hybrid and N fertilization effects were similar for fresh and ensiled corn forage.