Nitrogen and Potassium Fertilization Effects on Yield and Quality of Burley Tobacco

Field studies were conducted in 1983 and 1984 at Lexington, KY to examine the effects of N and K fertilizer on yield and chemical quality of burley tobacco ( Nicotiana tabacum L. cv. Ky 14). Treatments included: NH 4 NO 3 at rates of 112, 280, and 448 kg N ha −1 ; and two sources (K 2 SO 4 and KCl), each at rates of 0, 112, 224, and 448 kg K ha −1 . The following agronomic and chemical characteristics were examined: yield, price, leaf N, P, K, Ca, Mg, Cl, Mo, total alkaloid, and solanesol concentrations. Cured leaf yield, price, and solanesol concentration were strongly influenced by N × K interactions. Each was raised by increasing N rates when no K was applied; however, at higher K levels, increasing N rates resulted in smaller price increases, no yield changes, and reductions in solanesol concentrations. Reductions in cured leaf Mo concentration relative to N, K, and Mg levels with increasing K fertilization beyond 0 kg ha −1 were exaggerated as N rates were raised. No effect of N rates on total alkaloids or solanesol concentrations were noted while increased K rates increased concentrations of both. Greater cured leaf yields and Mo concentrations were achieved with KCl than with K 2 SO 4 . The positive effect of KCl on Mo concentration at low N application rates was reduced by increased N fertilization suggesting that Mo uptake was enhanced by Cl ‐ but reversed at high levels of NO ‐ 3 application.