CHANGES IN THE CONTENT OF SOME MACRONUTRIENTS IN BASIL HERBAGE INDUCED BY DIFFERENT NITROGEN AND POTASSIUM FERTILIZATION RATES*

This experiment, carried out in a greenhouse from February to May in 2008-2010, was designed to determine the effect of an increased rate of nitrogen and potassium on the content of phosphorus, calcium, magnesium, chlorine and sulphur in basil herbage as well as to trace relationships between a basil cultivar and changes in the mineral composi-tion of the herbage as influenced by the applied rates of nutrients. The mineral composi-tion of basil herbage was determined on the basis of an analysis of the growing substrate conducted after the harvest of the experimental plants. Two Polish cultivars of basil, called Kasia and Wala, as well as a green-leaved form popular on the domestic horticultural mar-ket, were grown from seedlings in pots (4 dm3) filled with sphagnum peat of the pH be-tween 5.5-6.0. The following amounts of nutrients were applied, expressed in g per 1 dm3 of the growing substrate: 0.2, 0.4, 0.6, 0.9 N in the form of ammonium nitrate; 0.4, 0.8 K in the form of potassium sulphate; 0.4 P as 20 % P superphosphate; 0.3 Mg in the form of magnesium sulphate monohydrate, as well as the following micronutrients (in g per 1 dm