Published on 08/04/01

Scientists Find EASY Way to Monitor Water Use

What do you get when you combine a washtub, chicken wire, a toilet bowl float and a few things from your local hardware store? You get a precise monitoring device that can help farmers save time, money and conserve water, say experts with the University of Georgia College of Agricultural and Environmental Sciences.

The device is the UGA EASY (Evaporation-based Accumulator for Sprinkler-enhanced Yield) Pan Irrigation Scheduler. It's designed to provide a simple, cost-efficient, low-maintenance way for farmers to know when or if their crops need water, says Kerry Harrison, a UGA CAES engineer.

"This irrigation scheduler is another alternative farmers can use to schedule irrigation that doesn't require a lot of investment or effort," says Harrison, who helped design the scheduler.

Photo:Brad Haire

The UGA EASY Pan Irrigation Scheduler is a low-cost, simplified way for farmers to monitor irrigation use.

Low investment

For many years, farmers have asked for a low-cost tool that could tell them precisely when to irrigate crops. So, Harrison, along with Dan Thomas, a CAES engineering professor, set out to develop such a tool.

Several higher-tech monitoring systems are available on the market. These systems can be expensive, require a computer to calculate readings and can be time consuming.

For about a $50 investment in common, but specific, components and another $50 of labor, almost anybody can make and use the EASY scheduler, Harrison said.

Meets the needs

The EASY scheduler addresses four basic needs for a irrigation monitoring device:
*It eliminates complicated math equations.
*It's easy to calibrate.
*It takes into consideration plant rooting depth.
*And it's easy to operate.

The EASY scheduler operates on a basic principle important to irrigation management known as potential evapotranspiration (PET). This is how much water can be removed from the plants (transpiration) and soil (evaporation) without compromising the water needs of the plants. By placing screen materials over the washtub, this device automatically reflects the PET of several crop situations. Chicken wire is used for peanuts. Screen door wire is used for cotton.

The device responds to water removal and water addition, like rainfall or irrigation.

The specific (#3 17-gallon Galvanized) size of the washtub eliminates the need for calibration.

The length of the rod attached to the toilet bowl float can be adjusted to consider the rooting depth of plants.

"With the indicator attached, you can read it just like a gas gauge to determine when or how close you want to get to empty before watering," Harrison said.

It's easy to use "as long as you put it in the field," Harrison said. "You don't even have to get out of the truck to check it."

Harrison recommends putting the device at the same height as the plant canopy for a true reading.

Photo:Brad Haire

Worth County farmer Johnny Cochran checks the EASY scheduler in his peanut field.

Works in the field

Worth County farmer Johnny Cochran is using the EASY scheduler in his fields this year. He's comparing it to a more expensive, computer-based system he also uses.

"You can tell somebody put a lot of thought into making it, but usually something this simple-looking doesn't work.," Cochran said.

Though the computer-based system can give more specific information, Cochran said, the EASY scheduler works just as well at telling when crops need or don't need water.

And that's important to him.

This time of year, most crops need about two inches of available water each week. It costs a farmer about $4 per inch of water per acre. One 100-acre field would cost the farmer $800 to irrigate per week.

"Farmers don't want to irrigate," Cochran said. "It costs money and time. But sometimes you've got to have it. With water use looking like it's going to be regulated more and more in the future, if you can get by without applying water, it's cheaper for the farmer and saves the water."

For information about the UGA EASY Pan Irrigation Scheduler, contact your county UGA Extension Service office.

Brad Haire is the former news editor with the University of Georgia College of Agricultural and Environmental Sciences.