NITROGEN APPLICATION RATE INFLUENCE ON YIELD, QUALITY, AND CHEMICAL CONSTITUENTS OF FLUE-CURED TOBACCO, PART I: APPLICATION TIMING

Research was conducted at 5 locations between 2012 and 2013 to determine the effect of nitrogen application rate and timing on yield, quality, and leaf chemistry of flue-cured tobacco. Urea–ammonium–nitrate was applied at 75, 100, and 125% of the recommended nitrogen rate for each specific field condition. All treatments were applied at differing intervals beginning at transplanting and concluding prior to or at topping. Yield data were collected postharvest, and leaf quality was determined according to U.S. Department of Agriculture grade. Crop value per hectare was quantified by a combination of yield and quality. Tissue samples were collected at layby and topping to evaluate total leaf nitrogen content at the respective growth stages. In addition, SPAD meter readings were collected at topping. Composite cured leaf tissue samples from all 4 stalk positions were analyzed for total alkaloid and reducing-sugar content. Data were subjected to analysis of variance (ANOVA) with the use of the PROC GLM procedu...