Mineral nutrition of chamomile (Chamomilla recutita (L.) K.

In field and pot experiments, we studied the effect of different nutrients (N,P, K, S, Ca and Mg) on the qualitative and quantitative characters of the Bulgarian cultivar Lazur from chamomile (Chamomilla recutita (L.) K). In the pot experiments, the optimal ratio between the macronutrients in the nutrient solution for achieving best quantitative results in chamomile cv Lazur was N:P:K = 40:28:32%, while the optimal ratio between the other elements was K:Ca:Mg = 40:38:22%; Nitrogen and potassium increased the yields, while phosphorus increased the essential oil content. Calcium was also found to be important for high yields and dry matter content in the herba. Sulfur and phosphorus increased inflorescence weight and essential oil content in them. In field experiments the highest yields of inflorescence and oil were achieved when the ratio between the major nutrients N:P:K was 1:1:1 (in 120 kg/ha active ingredients). Differences in the nutrient regimes induced some alterations in the essential oil quality. The (-)-alpha- bisabolol content was increased by elevated phosphorus levels, while higher content of magnesium in the solution sharply decreased its content. Hamazulene content in the oil was found to be a relatively more stable characteristic and was not affected greatly by variation of the tested nutrients in the solution.