'Dissolving oxygen in water is better for root growth'

Benjamin Vermeer of Vermeer Holland Consultancy is an international cultivation consultant and travels a lot around the worldwide horticultural scene. He sees that greenhouse vegetable growers worldwide are struggling with root diseases. Especially in situations with higher temperatures, roots become more sensitive to diseases. He notes this in Central and South America, but also in The Netherlands with the rising summer temperatures. “If you can increase the oxygen content in the water, you will get better root growth and healthier plants.” He had been looking into installations that add extra oxygen to the water for some time, but got the impression that this system could be improved.

No nano but ultra-fine bubbles

In collaboration with installer Lorenzo de Jong in Mexico and Dutch Greenhouse Systems in De Lier, he has developed a generator that adds ultra-fine bubbles to the water. The first machine of this 'Ultra-fine Dissolved Oxygen Bubble Generator' will be delivered to pepper company Royal Peppers this month. A-Growtech consciously does not use the word nanobubbles in its communications. “It’s better to talk about ultrafine bubbles instead of nanobubbles. That term is often used incorrectly, because the devices cannot make the bubbles that small,” according to Vermeer.

The new device differs from other products because of the way the oxygen is added to the water and the mixing which this produces.

“When enriching the irrigation water with oxygen, it is mainly about the extent to which the gaseous oxygen is mixed with the water,” he explains. “Growers are now often reminded of the oxygen content in their water that can be read on the oxygen meter, but that says nothing about the extent to which the oxygen has been dissolved.”

Solubility

When developing the generator, Vermeer et al. therefore looked at Henry's Law, which describes the solubility of a gas in water. According to this physical law, the degree of solubility depends on pressure and temperature. The higher the temperature, the lower the solubility. A-Growtech uses a high pressure for the oxygen input and can handle up to 25 mg oxygen per liter of water. The salinity of the water also plays a role, Vermeer knows.

The Dutch grower ‘Royal Peppers’ will be the first to use the generator. In addition, A-Growtech will soon supply a number of installations to greenhouse vegetable companies in Mexico. Vermeer: ​​“In terms of costs, a grower should take into account approximately 35,000 euros per 10 hectares. But this depends on how much oxygen he is going to add.”

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