Fertigation and Irrigation Triggering
Fertigation and irrigation triggering in Hydria 4+ Touch happens by means of the following:
1. Time triggerings; these can be fixed triggerings on a preset time-of-the-day basis,
2. External triggerings; these are controlled by external sensors (safety limits and time delays apply to this category). External triggerings can be further categorised under simple external triggerings (initiation of the irrigation/fertigation program), and plant-nursery type external triggerings, which are specifically designed for the filling of nutrient solution tanks, where both the initiation and termination of the filling process are controlled by an external sensor (e.g. nutrient level relay),
3. Solar radiation-based triggerings; with the addition of a light meter, we have the option to control the irrigation frequency based on the level of solar radiation in the greenhouse. In other words, irrigation triggering happens based on the integration of the solar radiation. Practically, this means that the irrigation of the crop will be more frequent on a sunny day as opposed to a cloudy day. This method of irrigation management may have a flaw; if the system is set (as far as the the desired drainage percentage is concerned) under conditions of low light intensity, then it will irrigate the crop excessively when the light intensity increases. The opposite will happen if the system is set under conditions of high light intensity. This issue is addressed in Hydria 4+ Touch, by employing an additional balance parameter, easily adjustable by the user.