Save Water and Grow More Food

The factor that has shaped human civilization more than any other is water. The extreme weather patterns due to climate change are increasing drought in some regions and extreme storms and floods in others. In California and the West, we are experiencing more intense drought. Given this shift, irrigation practices are key to achieving optimal water efficiency on farms and in urban landscapes. Drip irrigation has been widely adopted the past few decades. More recently, a new irrigation technology called GrowStream, designed to communicate directly with plants, is starting to be deployed.

This plant-responsive irrigation system is based on an understanding of plant physiology and organic chemistry. The groundbreaking research by Suzanne Simard over the past three decades reveals the complex, interdependent underground mycorrhizal networks of forest trees and how they communicate, learn, and share. Her work is the foundation for this “smart” irrigation system. The genius of this system is subsurface tubing infused with a pore-filled polymer that can sense a plant’s needs. When a plant gets thirsty, it releases a special chemical into the surrounding soil. The microporous tubing is poised to respond to these chemicals with the slow release of water and nutrients through its millions of micropores at a rate to match the roots’ absorption capacity. When the plant’s water craving is quenched, it stops emitting the thirst chemical, and the micropores close.

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Since the system is responding “real-time” to the plant’s signals, it can answer to the plant’s reaction to temperature and wind variations. Because the system is in sync with the plant’s requirements, there is less stress on the plant, resulting in more growth and higher yields. The tubing lines can run 1,200 feet, and since the tubing communicates directly with each individual plant, one line can support a variety of plant types. 

The system is easy to install and maintain; costs the same or less than other subsurface irrigation technologies; requires no sensors, valves, controllers, timers, or other electronic devices; and has no emitters to get clogged. A small machine is able to trench, roll out the tubing, and backfill in one pass. Most importantly, the efficient application of water reduces the amount needed by 30-50 percent over drip systems. Similarly, the ultra-low pressure and flow rates dramatically reduce pumping demands, yielding 40-70 percent savings on energy. 

The GrowStream system is being used in 14 countries, some in the Middle East and some in Africa. In the U.S., it is being tested on urban landscaping with the goal of increasing green cover and countering the heat-island effect. All considered, it has the potential to greatly reduce water scarcity and improve food security. The biggest hurdle will be getting farmers to change from existing methods of irrigation that are already established and paid for.

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