THE EFFECT OF NITROGEN SURPLUS IN FERTILIZING RATES APPLIED TO ECHINACEA-PURPUREA (L.) MOENCH - ON THE PRODUCTION OF ITS ACTIVE SUBSTANCES

Pot experiments were conducted to study the effect of nitrogen surplus in form of NH: and NO; in relation to the presence of ions Ca2+, Li+, Na+ from applied fertilizers, and the effect of SO42-, HCO3- and Cl- on the production of active substances in Echinacea purpurea (L.) Moen ch. The effect of carbon on nitrogen nutrition of plants was studied i n variants with additions of cattle dung, cattle manure, mustard, whit e clover, wheat straw with constant C contents, and parallelly with co nstant N content at different C : N ratios. Variations in nitrogen con tent in plants (N-min + N-tot) were examined in relation to variations inactive substances in plants. Variations in total, mineral and miner alizable nitrogen in the soil of vegetation pots were also studied. No significant difference was demonstrated between the forms of nitrogen applied by N-fertilizing and its effect on the content of active, sub stances in E. purpurea; the study of cation effects showed that contra ry to calcium effects the production of active substances was supporte d by univalent cations moderately but statistically significantly. Dif ferent effects of anions SO42-, Cl- and HCO3- are statistically insign ificant at fertilizing with ammonium nitrogen. Even though the C : N r atio is satisfactory, the production of active substances is reduced b y applications of organic manures apparently through an increase in mi neralizable nitrogen and a decrease in mineral nitrogen in the soil of vegetation pots. It is surprising that both fast and slow decomposabl e carbon sources, i.e. glucose and wheat straw, are ineffective in thi s aspect. Similarly like in the preceding variants, the largest immobi lization effects in variants with constant N contents in organic matte r additions were observed in mustard, not in straw as expected. Variat ions in the content of nitrogen forms in pot soil are surprisingly in good agreement with the production of active substances in E. purpurea plants. Variations in the contents N-min + N-tot in plants in relatio n to variations, in their contents of active substances have not only a nonlinear course but they are evidently a result of at least two dif ferent processes. A relation of the production of active substances in E. purpurea to increasing nitrogen rates expressed by an N-min: K rat io was also studied. Maximum production was attained at a 6 : 1 ratio in the soil used.