47th TWC, Tob. Work. Conf., 2016, abstr. 05

Dark fire-cured tobacco response to potassium application rate and timing

University of Kentucky, Princeton KY USA

Field experiments were conducted in 2012, 2013, and 2014 to evaluate dark tobacco response to potassium at a site near Murray KY that showed low to medium potassium levels in soil samples taken in the spring prior to tobacco transplanting. Soil test K at the site was 102 in 2012 (low, 290 lbs K/A recommended), 136 in 2013 (low, 260 lbs K/A recommended), and 212 in 2014 (medium-low, 190 lbs K/A recommended). Potassium was applied at the soil test recommendation, 0.5 x the soil test recommendation, or 1.5 x the soil test recommendation in either broadcast applications made the day before transplanting or banded applications (2 bands per row) made approximately 7 days after transplanting. Potassium sulfate (0-0-50) was the potassium source used in all applications. An untreated check was included that received no potassium. There was no response to potassium application timing, as vigor, yield, and quality were similar whether potassium was applied broadcast before transplanting or banded at one week after transplanting. Dark tobacco vigor, yield, and quality response to potassium rate was minimal in any year, but temporary potassium deficiency was seen in check plots that received no potassium. Treatments receiving potassium had higher yields than the untreated check. Slight increases in yield were seen in 2012 and 2014 as potassium rate increased from the 0.5 x to the soil test recommendation, but generally did not increase further as rate increased to 1.5 x the soil test recommendation. Quality was generally similar in all treatments that received potassium, and higher than in the untreated check. (Reprinted with permission)