GROWTH RESPONSE TO NITROGEN AND POTASSIUM FERTILIZATION OF COMMON BASIL (Ocimum basilicum L.) PLANTS

Curative and aromatic properties of basil herb make this species appear more and more frequently in field and glasshouse cultivations. Growth and yielding of basil plants depends, among others, upon the cultivar and fertilization. The experiment was conducted in a glasshouse, in the period from February to May 2009-2010. Plants were grown in pots of the capacity of 4 dm(3), filled with peat substrate. Nitrogen (administered in the form of ammonium saltpeter) concentration in the substrate was differentiated: 0,2; 0,4; 0,6; 0,9 g N. dm(3), as well as that of potassium: 0,4; 0,8 g K. dm(3), given in the form of a sulfate. The plants of three examined basil cultivars (Kasia, Wala, green leaved form) differed in average height, number of branchings, size of leaves, as well as the weight of fresh and air-dry herb. The application of nitrogen fertilization significantly differentiated the mean height and length and width of leaf blades in basil plants that decreased as the dose of this nutrient increased. Plants fed with the lowest and medium dose of nitrogen had significantly higher weight of fresh and air-dry herb, compared to the plants obtaining the highest dose. The amount of fresh herb of the examined plants remained under significant influence of the co-operation. The fresh herb weight of the examined plants remained under significant effect of cooperation between the cultivar and nitrogen dose. No significant effect of potassium dose was found upon the examined biometric features of basil plants. The interaction between nitrogen and potassium in the formation of basil growth and development was only demonstrated with reference to the height of plants and width of the leaf blade.