Response of Calendula officinalis L. Plants to Different Nitrogenous Fertilizers
Calendula officinalis L. plants were fertilized with urea (46% N), ammonium nitrate (31% N), and ammonium sulfate (20% N) at 0, 25, 50, or 100 kg N/Feddan (4200 m2). The plants also received calcium superphosphate (15.5% P2O5) and potassium sulfate (48% K2O) at 100 and 50 kg/Feddan, respectively. The results showed that fertilizers enhanced vegetative growth and improved flowering aspects compared to control plants. Application of urea at 50 kg N/Feddan gave the highest flower number (119) and flower dry weight (183 g). Moreover, the applied fertilizers increased the content of photosynthetic pigments (chlorophyll a, chlorophyll b, and carotenoids) in leaves and flowers and the N percentage in shoots. Nevertheless, P and K percentages were decreased.