2018 Volume 17 Issue 1 Pages 95-103
The new root-zone environmental control system (N.RECS) was developed by combining floor heating panels, an air-source heat pump cold/hot water supply system, and heat-insulating pot container. N.RECS has 2 modes, which are heating and cooling modes of root-zones. The heating mode was able to maintain the root-zone temperature at 25°C at a 10°C air temperature during the winter season, and the cooling mode could provide a 23°C root-zone temperature at a 40°C air temperature during the summer season. The effects of root-zone heating during the winter season on growth and flowering in dahlia (Dahlia × hybrida) were investigated. The plants were grown in plastic houses with minimum air temperatures/root-zone temperatures of 15°C/non-heating, 12°C/24°C and non-heating/24°C. The growth of plants cultivated at 12°C/24°C and non-heating/24°C were promoted compared with that of 15°C/non-heating. The flowering time of non-heating/24°C was 2 to 3 days late at 15°C/non-heating. The cost of the consumption of energy for heating was estimated to be 34 and 69% lower at 12°C/24°C and non-heating/24°C, respectively compared with that of 15°C/non-heating. Fuchsia (Fuchsia × hybrida), with poor heat tolerance, was used to investigate the effects of root-zone cooling on growth. When the plants were cultivated with non-cooling of the root-zone during the summer season, 48% of the plants wilted and died. However, root-zone cooling at 20°C or 23°C resulted in the healthy development of plants. Thus, it is indicated that N.RECS is useful for the growth regulation of pot flowers year round.
