EFFECT OF COMPOST FERTILIZATION RATES ON GROWTH, YIELD AND SOME ACTIVE CONSTITUENTS OF TWO VARIETIES OF CALENDULA OFFICINALIS

Abstract

• All examined fertilization treatments had a positive effect on growth of the two cultivars (Yellow and Orange) of Calendula officinalis when compared to the no-fertilized control which is quite obvious. • Mineral N, P and K fertilization proved to be more effective than compost in influencing growth of the two cultivars of Calendula officinalis, regardless of compost levels tried (25%,50%,75% or 100%).This was forecasted too since mineral fertilization, presumably in most cases, makes nutrient elements available and absorbed by plants in a readily manner. • The yellow cultivar of Calendula officinalis was superior than the orange cultivar in all growth parameters studied, i.e. plant height, above-ground fresh and dry weights, number of flowers/plant and in both flower diameter and dry weight. Whereas, the orange cultivar was exclusive than the yellow cultivar in some internal chemical constituents analyzed, i.e., P total carbohydrates, and in both polyphenols and flavonoids contents. • When mineral fertilization level was reduced to 75 % and replaced with 25 % compost, the obtained results could be summed up as follows: – All growth parameters studied, i.e. plant height, above-ground fresh and dry weights was less by 8.4 %, 6.3 %, and 8.5% when compared to 100% mineral in both cultivars for the1st and 2nd season.