The effect of potassium rate on the yield and quality of flue-cured tobacco (Nicotiana tabacum L.)

Research was conducted at 2 locations in 2009 and 2010 to determine the effect of potassium rate on the yield and quality of flue-cured tobacco. Treatments included 8 rates of potassium from sulfate of potash magnesia (K-Mag, 0–0–22): 0, 84, 112, 140, 168, 196, 224, and 252 kg K2O ha−1. A complete (N–P–K) fertilizer that supplied 134 kg K2O ha−1 was also included as a control treatment. All fertilizer was applied in a single band application within 10 days after transplanting. Yield was measured and samples were assigned an official U.S. Department of Agriculture (USDA) grade. Crop value was determined based on yield and grade. Tissue samples were collected throughout the season at 3 separate times: at layby, at topping, and after curing. Tissue samples were analyzed for total alkaloid and reducing sugar content as well as N, P, K, and Mg content at North Carolina State University. Soil samples were also collected at transplanting, which corresponded with potassium fertilizer application, and were analyze...