48th TWC, Tob. Work. Conf., 2018, abstr. 08

Dark air-cured, dark fire-cured, and burley tobacco TSNA in response to potassium source and rate

University of Kentucky, Lexington KY USA

Field trials were initiated at the University of Kentucky Research and Education Center in Princeton, KY in 2016 evaluating the effect of potassium source and application rate on tobacco-specific nitrosamine (TSNA) content in dark tobacco. These trials were extended to Murray State University in Murray, KY and a burley trial was added at the Agricultural Experiment Station Spindletop Farm in Lexington, KY in 2017. In 2016, dark tobacco variety used in both trials was KT D14 low converter (LC). In 2017, NL Madole high converter (HC) variety was added in the dark air-cured (DAC) and dark fire-cured (DFC) trials at Princeton and Murray. Burley varieties TN90 LC and TN90 HC were used at Lexington. Potassium was broadcast applied the day prior to transplanting at 100, 200, and 300 lbs K2O acre-1 as potassium chloride (KCl) or potassium sulfate (K2SO4). An untreated control was also included. In 2016, the DAC trial had significantly lower TSNA than the DFC trial. There was also a potassium source effect in the DAC trial with KCl resulting in lower TSNA levels than K2SO4. KCl treatments yielded significantly higher than K2SO4 treatments in the DAC trial, but this yield difference was likely associated with significantly higher leaf moisture content in cured tobacco from plots receiving KCl. There were no differences in quality grade index (GI) between KCl and K2SO4 sources in 2016. In 2017, plots treated with potassium yielded higher than untreated plots in dark trials and LC selections yielded higher than HC selections in dark and burley trials. KCl treatments had a higher GI in three of the four dark trials. Higher rates of potassium resulted in a higher GI in the DFC trial at Princeton. Untreated burley tobacco yielded significantly less than all other treatments except for potassium chloride at 100 lb ac-1 in Lexington. (Reprinted with permission)