Effect of Several Controlled-Release Fertilizers on the Growth of Four Foliage Plants

Abstract

Five types of controlled-release fertilizers were evaluated in individual experiments on Dieffenbachia amoena Bull., Philodendron scandens subsp. oxycardium Shott. Bunt. and Ficus benjamina L. Precise 12.0N-2.6P-5.0K (12-6-6) an encapsulated liquid fertilizer, applied at 656 kg (569 lb/A) N per ha per year, produced similar Dieffenbachia and Philodendron plant dry weights as 5 impregnated vermiculite and one ureaformaldehyde applied at higher rates of N. In a comparison with a water soluble 20.0N-8.7P-6.6K (20-20-20) fertilizer on Brassaia actinophylla Endl., dry weights and foliage color ratings of Brassaia plants fertilized with the water soluble fertilizer were greater than those of plants receiving the controlled release fertilizers. Ficus height, visual rating, dry weight and differences in green color values of leaves of plants fertilized with Precise 12.0N-2.6P-5.0K (12-6-6) were greater than those receiving other controlled-release fertilizer treatments. In a second experiment, Ficus plants fertilized with high rates of several controlled-release fertilizers and Scott Pro-Grow 25.0N-2.2P-8.2K (25-10-10) rates were equal or better in growth than plants receiving Precise and Osmocote 14.0N-6.1P-ll.6K (14-14-14). Mag Amp 7.ON-I7.4P-4.1K (7-40-6) plants treated with 900 kg/ha (784 Ib/A) and 1200 kg/ha (1045 lb/A) performed poorly in all growth parameters measured. Plant growth from high rates of controlled-release fertilizers surface applied at the beginning of the experiment was equal to that produced with 20.0N-8.7P-16.6K (20-20-20) soluble fertilizer applied weekly at the rate of 1582 kg N/ha (1477 lb/A) per year.