CLIMATE CONTROL BASED ON STOMATAL BEHAVIOR IN A SEMI-CLOSED GREENHOUSE SYSTEM 'AIRCOKAS'

Climate control in a greenhouse is usually based on maintaining a specific air temperature, sometimes adjusted to the available light level or the cost of energy. According to theoretical physiological knowledge optimal photosynthesis depends on the behavior of the stomata. No existing climate control strategy is based on measurement or modeling of the stomatal opening. A soft-sensor based on a crop energy-balance equation was developed. The validation of this sensor was started, but the method using a porometer and a silicone rubber impression proved to be inappropriate. A climate control strategy for stomatal opening based on the use of a high pressure misting system, an energy-balance equation and adjusted ventilation window control was developed. This system with the name ‘Aircokas’ was introduced in commercial greenhouse operations and used for various crops. A new approach for the representation of stomatal conductance is suggested.