Effect of Controlled Irrigation Methods Using Climatic Parameters on Yield and Quality of Hydroponic Cut Roses

The effects of different irrigation control methods based on climatic parameters on yield and quality of a cut rose soilless crop (Rosa 'Red France') were studied. Four control methods were evaluated: the first was based on integrated solar radiation (ISR) and performed when a preset amount of accumulated radiation (500 kJ/m(2)) was reached; the second was based on greenhouse air temperature (GAT) and activated when 28 degrees C threshold was exceeded; the third was regulated on internal air relative humidity (ARH) and activated when values dropped 50% threshold; the fourth was a time clock program (TCP, control). Irrigation control methods did not affect the production of cut stems (average 19.7 stems/plant in all four treatments). ISR irrigated plants produced longer (58.3 cm) and thicker stems (8.1 mm) and were characterized by lower water supply as well higher water use and WUE than roses irrigated with other control methods. GAT, ARH and TCP were less effective and provided excessive amounts of water to the plants. ISR proved to be the most effective irrigation control system since, though more restrictive with water supply, it did not limit plant growth neither cut flower production or quality.