Irrigation dose according to substrate characteristics, in hydroponic systems

• Main Author: Mavrogianopoulos Giorgos N.
• Format: Article
• Language: English
• Published: De Gruyter 2016-01-01
• Series: Open Agriculture
• Subjects: irrigation efficiency; hydroponics; water use efficiency; water saving; fertilizers saving; substrate salinity; easily available water; open hydroponic systems
• Online Access: https://doi.org/10.1515/opag-2016-0001

The correct supply of water and nutrients is very important in hydroponic growing systems in order to use water and fertilizers efficiently and avoid stress situations. Usually, in low-cost hydroponic greenhouses using open hydroponic systems, the supply of water and nutrients is performed with a constant irrigation frequency, changing the dose to ensure that each irrigation cycle (each day) delivers the amount of nutrient solution needed for the plants, plus an additional 20 to 30% leaching fraction. This type of irrigation control may result in suboptimal conditions in many periods of time, although the total amount of irrigation solution supplied to the crop may be much larger than required. For an efficient irrigation the present theoretical study proposes that in open hydroponic systems there is a significant possibility to preserve water and nutrients, by shifting the irrigation control from a changeable irrigation dose according to evapotranspiration to an irrigation dose calculated according to the amount of used substrate in the bag, the characteristics of the substrate and the salt concentration of used water. The frequency of irrigation is recommended to be performed according to evapotranspiration. The proposed irrigation control is more rational than the currently used control method as it takes into account the characteristics on water holding capacity of the used substrates, resulting to a conservation of fertilizers and water.