GREENHOUSE ROSE PRODUCTIVITY AND NUTRIENT STATUS IN RESPONSE TO FERTILIZATION WITH A CONTROLLED-RELEASE FERTILIZER

Rose plants, ‘Bridal Pink’ budded on Rosa manetti, were grown in 15-liter pots filled with a peat: vermiculite: perlite medium (3:2:1 v/v). They were fertilized with either a complete nutrient solution adjusted to provide 112, 16 and 117 mg L^-1 N, P and K, respectively or the controlled-release fertilizer (CRF) Osmocote^™ 18-6-12 (rated for a 8-9 month release period) at a rate of 7 kg m^-3 of substrate (total of 105 g/pot). Cultural practices and irrigation management (volume and application frequency) were the same for both treatments.
No significant differences in flower yield, plant biomass (fresh weight yield per plant) and average flower shoot length were observed between the two fertilization methods after five flushes of growth and flowering (8 months). Monitoring of soil solutions (extracted from rootzone) and leachates (drainage) showed that CRF-fertilized plants had significantly higher electrical conductivities and nitrogen (N) concentrations than fertigated plants, but most values of these nutritional parameters were within recommended ranges.
Leaf tissues of flowers harvested from the CRF plants had significantly lower Ca and higher Mg and B concentrations than in fertigated plants, but these and the rest of nutrients were within recommended ranges.
These results warrant further and detailed research attention to the potential utilization and management of CRF fertilization in greenhouse roses.

IV International Symposium on Rose Research and Cultivation

R.I. Cabrera

controlled-release fertilizers, flower yields, liquid feeding, nutrient leaching, Osmocote, tissue nutrient concentration

https://doi.org/10.17660/ActaHortic.2007.751.7