Fertility – Using Liquid Nitrogen (UAN) Sources for Nitrogen
Considerable attention has been given in recent years to using liquid ammonium form of nitrogen for tobacco. This has been spurred in part by the cost of nitrate nitrogen fertilizers and the inconvenience of applying large amounts of dry fertilizer. Research conducted in North Carolina over the last decade has consistently shown that fertility programs utilizing all nitrate or all UAN forms of nitrogen produce similar yield and leaf quality.
The bottom line on the ammonium versus nitrate issue is that under our conditions, nitrification rate is rapid enough that UAN products, such as 30 percent and 24S, that contain 75 percent of the nitrogen as ammonium, are equally acceptable nitrogen sources as all nitrate products, such as calcium nitrate. Growers should feel comfortable using any of these products, with the decision based on factors such as application technology and cost, because crop response is not an issue.