The Effects of Recommended Rates of Nitrogen and Foliar Fertilization on Dark-Fired Tobacco.

The recommended rates of nitrogen for the production of dark-fired tobacco are 300 lbs./acre in Kentucky and 250 lbs./acre in Tennessee. In the past, many producers have used in excess of 400 lbs./acre of soil-incorporated nitrogen in addition to spraying foliar fertilizer throughout the growing season. Studies have been conducted from the year 2000 to the present in Princeton, Kentucky, and in Springfield, Tennessee. The same study was started in Murray, Kentucky in the year 2001, and conducted again in 2002 as a joint project between the University of Kentucky and Murray State University. The purpose of this study is to determine the optimum rate of incorporating nitrogen and investigates the effects of foliar fertilizer on dark-fired tobacco. The study was repeated in 2002 with irrigation because many growers who had incorporated irrigation with high rates of nitrogen fertilization, reached yields in excess of 4000 lbs./acre versus the 2500-3200 lbs./acre achieved in the research plots, which were not irrigated. The experiment utilized a split-plot design arranged in a randomized complete block with three replications. The plots consisted of 200, 300, 400 lbs. nitrogen acre incorporated, and subplots of three foliar fertilizer products applied every two weeks after transplanting with an unsprayed check, with 100 or 200 lbs. of nitrogen/acre side dress into the remaining plots to obtain 300 and 400 lbs. nitrogen/acre. Data from the previous study indicate there is no additional benefit of high nitrogen rates of foliar fertilizer in dark-fired tobacco. When the yields are obtained, statistical differences may be observed for the 2002 data due to irrigation