Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 12/1/2016
Publication Date: 12/15/2016
Citation: Coblentz, W.K. 2016. N fertilization for improved forage yields has little impact on nutritive value. Popular Publication. p. 10. Midwest Forage Focus. December 2016. Midwest Forage Association. St. Paul, MN..
Technical Abstract: Applications of soil amendments or fertilizers containing nitrogen are a routine part of most grass forage management strategies, with the primary goal of improving forage yields. But an increase in yield is usually accompanied by a decrease in nutritive value. In order to better evaluate this tradeoff, we evaluated the effects of nitrogen fertilization on the nutritive value of a single cultivar (ForagePlus) of fall-grown oat fertilized at planting with six different rates of urea (nitrogen) or two rates of dairy slurry. Concentrations of fiber components increased consistently with nitrogen fertilization, while water-soluble carbohydrates (sugars) exhibited the opposite response. Overall, the forage nutritive value of fall-grown oat declined mildly in response to nitrogen fertilization, but these responses were not nearly strong enough to offset the advantages obtained by improved forage yields. This study provides forage growers with the knowledge that fertilizing for improved yields will not greatly reduce the nutritive value of fall-grown oat forage fed to dairy cattle.