Physiological Changes Involved in the Use of Calcium Cyanamide as a Slow-release Nitrogen Fertilizer in Impatiens wallerana (Hook.f.)

Root growth of bedding plants in small pots is usually restricted and evidently influenced by substrate quality and fertilization routine. Two pre-transplant 50- and 288-plug cells tray-1 were used. Plants were grown in two growing media and fertilized with liquid feeding and pre-transplant supply of calcium cyanamide (CC). CC-fertilized plants showed higher fresh-dry weight, glucose content and nitrogen content. The higher dry weight accumulation in CC-fertilized plants was supported by the increase in the relative rate of leaf area expansion (RLAE) and the increase in the rate of leaf appearance (RLA). The changes in leaf area were associated with increase in both leaf number and leaf size. CC-fertilized plants also showed a higher relative growth rate (RGR), mainly associated with higher net assimilation rates (NAR) and a change in photo assimilate partitioning that favoured shoots and specifically stems. From a grower’s point of view, the use of calcium cyanamide to fertilize I. wallerana plants in substitution of the traditional liquid fertilization system would increase crop productivity. Calcium cyanamide would be a better alternative than other coated products used as controlled-release fertilizer, especially under a global temperature increase or low environmental greenhouse facilities.