Abstract

In order to investigate the effect of nitrogen and potassium fertilizers on yield, quality and some quantitative parameters of flue-cured tobacco, 2 year experiment was carried out in tobacco research institute of Rasht located in Guilan province on factorial based with 3 replications. The applied fertilizer levels included 35 (N1), 45 (N2), 55 (N3) and 65 (N4) kg N/ha of pure nitrogen of urea source and potassium in two levels of 150 (K1) and 200 (K2) kg K/ha of potassium sulphate. The measured parameters in this experiment included leaf dry weight, leaf wet weight, stem height, stem diameter, leaf number in plant, leaf length, leaf width, stem dry weight, biomass, nicotine and sugar content. The effect of year on parameters such as leaf dry weight, leaf wet weight, stem height, leaf number, leaf length, stem dry weight, biomass and sugar content was significant (P<0.01). Likewise nitrogen had significant effect on leaf wet weight, leaf length, stem dry weight, biomass and sugar content at 1% statistical level and also on leaf dry weight, leaf wet weight, stem diameter, leaf width and stem dry weight at 5% statistical level. The interaction between year and nitrogen on parameters of leaf length (in 1% statistical level), leaf width and biomass (at 5% statistical level) was significant. In second year, more leaf dry weight, leaf wet weight, stem height, leaf number, stem dry weight, biomass and sugar content were obtained but the amount of leaf length and sugar content were greater in first year of experiment. The highest amount of leaf dry weight, leaf length, stem dry weight and biomass belonged to applying 35 kg N/ha and the greatest amounts of leaf wet weight and sugar content obtained when 35 and 45 kg N/ha was applied respectively. The greatest amounts of stem diameter and leaf width obtained when 35 and 55 kg N/ha was applied respectively. The highest sugar content was derived when 200 kg K/ha and was applied. Usage of 35 kg N/ha plus 200 kg K/ha led to the greatest amount of leaf dry weight, leaf wet weight, stem diameter, leaf number, leaf length and biomass. The highest amounts of leaf width and stem dry weight were gained when 35 kg N/ha plus 200 kg K/ha and 55 kg N/ha plus 200 kg K/ha were applied.

Key words: Nitrogen, potassium, yield, quality, quantitative characteristics of flue-cured tobacco.