Study debunks claims of smart irrigation controllers

Today's smart controllers for irrigation systems might not be as water-efficient as companies claim, according to new research out of Texas A&M University.

Scientists at the Texas AgriLife Extension Service tested six devices currently on the market that use weather data to determine how much water is needed. The researchers found that the devices used between one-third and two-and-a-half times more water than necessary.

Such devices use sensors or the Internet to capture data such as rainfall, temperature, solar radiation, wind speeds, and humidity. The devices then analyze the data, releasing the necessary water to compensate for the evaporation and plant transpiration, also called evapotranspiration.

The biggest problem occurs in sensors that use data from the Internet because it often reflects conditions at a local airport, not the actual site. Sensors that use on-site data used 70 percent less water than controllers using Internet data, according to the study. The most accurate controllers also monitored solar radiation, the researchers found.

However, the researchers noted that smart controllers offer significant opportunities for efficient water use when compared to manual irrigation, which applies about twice as much water as is needed.

"The technology shows good promise but it definitely needs upgrading," said Charles Swanson, an associate at AgriLife Extension, in a news release.

Swanson and Guy Fipps, an AgriLife Extension engineer and director of the Irrigation Technology Center,  conducted the study over an eight-week period in Texas.

Texas A&M researchers are involved in a number of water and agriculture projects.

Last year, water engineers from consulting firm Black & Veatch tapped Texas A&M to assist in a project evaluating zero-liquid discharge desalination of brackish water that contains high concentrations of natural organic matter in order to combat increased water demand in Florida (see U.S. water challenges spark research efforts).

Earlier this year, Houston, Texas-based Terrabon revealed that it licensed Texas A&M's technology to turn municipal solid waste into potable water and transportation fuel. The technology can also be used as new method of desalination using highly efficient heat exchangers (see New low-energy desal process could be used to make biofuels).

In 2007, Chevron and the Texas A&M Agriculture and Engineering BioEnergy Alliance began researching the production and conversion of crops for manufacturing ethanol and other biofuels from cellulose (see Chevron pumps more money into university biofuel research).  

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