The effect of different amounts of ammonium and calcium in food solution on the nutritional status, performance and quality of roses

In order to investigate the effect of nitrogen form (ammonium and nitrate) and different levels of calcium in nutrient solution on the quantitative and qualitative yield of cut rose (Rosa hybrida L.) cultivar Vendentta, under soilless cultivation conditions, an experiment was conducted in the greenhouse of the National Research Station of Flowers and Ornamental Plants (Mahalat). The experiment was factorial in a randomized complete block design with two factors: ammonium at three levels (0, 2.5, and 0.5 mM, out of a total of 10 mM nitrogen and the rest in the form of nitrate) and calcium at two levels (1.6 and 4.8 mM). The results showed that increasing the ammonium concentration in nutrient solution from 0 to 2.5 mM increased the number of flower stalks, peduncle length, and flower stalk fresh weight. While 5 mM ammonium concentration significantly reduced the number of flower shoots, calyx diameter, calyx length, postharvest life and fresh weight of flower shoots. Increasing the calcium concentration of the nutrient solution significantly increased the calyx diameter and fresh weight of flower shoots. With the application of ammonium in the nutrient solution (increasing the ratio of ammonium to nitrate), the calcium and potassium concentrations of the leaves decreased and the concentrations of phosphorus, zinc, manganese, iron and boron significantly increased. Increasing the calcium concentration of the nutrient solution significantly increased the concentrations of nitrogen, calcium, manganese and boron and significantly reduced the concentrations of potassium, zinc and copper rose leaves. According to the results of this experiment, the application of 2.5 mM ammonium (25% of the total nitrogen of the nutrient solution) together with 4.8 mM calcium improved the growth and some quality indicators of the Vendentta rose cultivar.