Effect of Different Concentrations of Nitrogen, Phosphorus and Potassium on Growth Indices of Oriental Lily (Lilium spp.) Bulblet

Bulblets require suitabale environmental conditions and particularly fertilization to obtain flower size. For this purpose, in a  CRD-based factorial experiment with four replications and 6 plants per replication, the effect of different concentrations of nitrogen, phosphorus and potassium on the growth of oriental lily bulbs of cultivar ‘Candy club’ was investigated. Treatments included different concentrations of nitrogen (100 and 160 mg L-1), phosphorus (40 and 80 mg L-1) and potassium (150, 225 and 300 mg L-1). Solutions containing elements with the desired concentrations were added to the hydroponic culture medium and after 10 months, growth indices were measured. The results showed that the highest number of leaves, shoot fresh weight, root fresh and dry weight, leaf potassium content and amount of soluble sugar and starch of bulbs were related to N: P: K treatment equal to 160: 80: 300. The highest leaf nitrogen content was observed in 160 mg L-1 treatment, the highest leaf phosphorus content in 80 mg L-1 phosphorus treatment and the highest leaf potassium content was observed in the interaction of nitrogen and phosphorus with concentrations of 160 and 80 mg L-1, respectively. The interaction of nitrogen and phosphorus with a ratio of 160: 80 also caused the highest leaf area, shoot dry weight, bulb fresh weight, bulb diameter, chlorophyll content of the leaf at the active growth stage and at harvest time (onset of dormancy symptoms). The highest bulb weight was observed in nitrogen and potassium treatments with concentrations of 160 and 300 and phosphorus and potassium with concentrations of 80 and 300 mg L-1, respectively. In general, the largest bulbs were produced at the highest levels of nitrogen, phosphorus and potassium used in the experiment.