CORESTA Congress, Online, 2020, Agronomy/Phytopathology Groups, AP 14

A comparison of traditional and alternative fertilizer programs for flue-cured tobacco production

North Carolina State University, Department of Crop & Soil Sciences, Raleigh, NC, U.S.A.

Previous fertilizer research in flue-cured tobacco has compared a wide range of nutrient programs, ultimately demonstrating the usability and function of numerous sources. The objective of this study was to investigate the influence of nitrogen (N) based sources on the assimilation of other macro and secondary nutrients. Research was conducted in two environments in 2019 to evaluate various combinations of basal and sidedress N sources. Basal treatments consisted of granular 6-6-18 or liquid 28-0-0 urea-ammonium nitrate (UAN) and potassium sulfate (0-0-50). Sidedress N sources were ammonium nitrate potassium (ANK), ammonium nitrate sulfate (ANS), or UAN, which were applied four weeks after transplanting. Each basal and sidedress source was paired to create a two x three factorial treatment arrangement. Four weeks after transplanting, the analysis of foliar tissue samples revealed higher concentrations of phosphorus and potassium in treatments containing 6-6-18 (0.36 and 3.31 %, respectively) relative to UAN and potassium sulfate (0.29 and 3.04 %, respectively). Foliar concentrations of macro and secondary nutrients were similar at flowering, with the exception of sulfur, which was lowest in the UAN + UAN treatment. After curing, foliar potassium was greatest in treatments containing 6-6-18 + ANK (2.12 %) relative to 6-6-18 + UAN (1.78 %), UAN + UAN (1.80 %), and UAN + ANK (1.57 %). Despite differences in foliar nutrient concentrations, cured leaf yield, quality, price, and value per hectare were similar, meaning that each of these fertility programs is likely suitable for use in tobacco production. This point is reinforced by the fact that nutrient concentration was deemed sufficient within each sampling interval, regardless of treatment. With the knowledge that practical differences are unlikely to be documented across the programs we evaluated, commercial farmers are encouraged to consider fertilizer price rather than performance when considering these nutrient sources.