Nitrogen and potassium fertilization effects on yield and quality of burley tobacco

Abstract

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: NH₄NO₃ at rates of 112, 280, and 448 kg N ha^-1; and two sources (K₂SO₄ and KC1), 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 X 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 KC1 than with K₂SO₄. The positive effect of KC1 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.