An experiment of rose cultivation in a closed hidroponic system was carried out from October 1996 to May 1998. The aim was to evaluate a simple equipment suitable for the management of the nutrition, in a closed system of low input for small floricultural farms. Seldomly chemical analysis of nutrient levels in the drainage solution and subsequent regeneration are proposed as substitutes of sensors for continuous adjustment of pH and concentration. The method was tested in a system provided with two tanks and one pump. One tank placed in a higher position was intended for storage of exhausted nutritient solution (Electrical Conductivity > 4000 mS/cm) and regeneration after chemical analysis. The second tank in a lower position was intended to receive the drained solution after distribution to the substrate. Such drained solution was mixed with fresh nutrient solution, when ever necessary, for redistribution. In case of storage of the exhausted drained solution in the upper tank, a fresh nutrient solution would be supplied in the lower tank and recirculated. Electrical conductivity was monitored daily in the lower tank. This paper relates data of 18 months of rose growth in soilless culture with continued recirculation. Good productive results were observed. A noteworthy reduction in water consumption and a high level (90-95%) of nutrient utilization were achieved. The method proved to be useful for cost reduction and was environment friendly, and improved the water and fertilizer use efficiencies, as well as quality and produtivity of roses.
rose; soiless; closed systems
