Using Dissolved Oxygen in Agricultural Farming

February 20, 2020

Dissolved oxygen can drastically increase a plants ability to utilize nutrients and defend against pathogens, while increasing yields and significantly decreasing plant shrink. Dissolved oxygen (DO) is the measure of how much oxygen is dissolved in water. DO naturally enters water through direct absorption, rapid water movement, and as a byproduct of underwater plant photosynthesis.  DO is strongly influenced by temperature and water salinity. Cold, clean, and pure water holds the highest quantities of dissolved oxygen. High levels of DO are desirable, but oftentimes in commercial greenhouses and hydroponic grow systems, there isn’t a simple way to increase DO.  Why does dissolved oxygen matter for greenhouse and hydroponic grow systems?  Improves root systems  Dr. Paul R. Fisher states, “Many growers are unaware of the level of oxygen present in their irrigation water or that raising the level of oxygen in the water will produce a plant with a better root system.”   According to Dr. Fisher, dissolved oxygen is especially important in hydroponic grow systems: “In hydroponics, where the roots are bathed in water, it is very important that there is enough oxygen dissolved in the water because that’s the only way roots are going to get oxygen for their healthy…

Dissolved oxygen can drastically increase a plants ability to utilize nutrients and defend against pathogens, while increasing yields and significantly decreasing plant shrink.

dissolved oxygen water

Dissolved oxygen (DO) is the measure of how much oxygen is dissolved in water. DO naturally enters water through direct absorption, rapid water movement, and as a byproduct of underwater plant photosynthesis

DO is strongly influenced by temperature and water salinity. Cold, clean, and pure water holds the highest quantities of dissolved oxygen. High levels of DO are desirable, but oftentimes in commercial greenhouses and hydroponic grow systems, there isn’t a simple way to increase DO. 

Why does dissolved oxygen matter for greenhouse and hydroponic grow systems? 

Improves root systems 

Dr. Paul R. Fisher states, “Many growers are unaware of the level of oxygen present in their irrigation water or that raising the level of oxygen in the water will produce a plant with a better root system.”  

According to Dr. Fisher, dissolved oxygen is especially important in hydroponic grow systems: “In hydroponics, where the roots are bathed in water, it is very important that there is enough oxygen dissolved in the water because that’s the only way roots are going to get oxygen for their healthy growth and respiration.”

Root elongation and density was found to be positively affected by increasing aeration. By increasing the dissolved oxygen to 8 mg/l, Dr. Sonja Maki, assistant professor in the Department of Plant and Earth Sciences at the University of Wisconsin-River Falls, found increased branching, length, and better weight in her crown pea roots

Increases nutrient uptake

Increased levels of DO stimulate root growth and health. In turn, increased root health directly translates into more efficient nutrient uptake. In particular, the fine root hairs that develop in increased quantities and under ideal conditions are responsible for the majority of water and nutrient uptake.

Reduces harmful bacteria counts

Water treated with DO produces healthier plants because the DO is able to eliminate bacteria that can be harmful to plant growth. High percentages of DO reduce the harmful bacteria count, and destroy  pathogenic bacteria to thrive in an anaerobic environment. 

Bolsters plant health & increases yields 

One study found that by increasing DO levels to 20-30 mg/L, growers were able to improve lettuce plant growth under a low greenhouse temperature in a deep hydroponic culture. The dry weight of the plant was over 100% greater than the control

 

Irrigation system pipes and water conditions contribute to levels of DO. 

Irrigation water delivered through the pipes in your fields or indoor growing area can have a detrimental impact on the health of your plants. The reason for this is because biofilm can colonize and grow on pipe surfaces. 

Biofilm is the thick layer of green or brown scum often seen lining the insides of pipes. Biofilm is a significant contributor to plant diseases because it can host bacteria, viruses, toxic algae, fungi, E. coli, and other harmful pathogens. In addition, the various microbes in biofilm colonies consume oxygen, resulting in water with low DO levels.

Treating Biofilm in Irrigation Systems is critical to plant growth.

Clean pipes in the irrigation system help maintain higher levels of DO. As previously stated, we want to maintain higher levels of DO so that plants can grow more effectively. 

Chlorine has been the standard means of treating and controlling biofilm growth in irrigation systems. But many farms are finding that ozone based water treatment systems are more effective in removing biofilm deposits and eliminating free-floating bacteria, while leaving greater amounts of DO in the water. This is because ozone has been shown to not only kill bacterial biofilm on contact, but also detach the biofilm matrix from pipe surfaces, making recolonization more difficult, all without leaving any negative residues which might be harmful to plants. 

The Watson Ozone Water Treatment System increases dissolved oxygen while sanitizing irrigation systems. If you would like more information please contact Watson Well.

California Groundwater Association
National Groundwater Association