Released July 11, 2008

LINCOLN, Neb. — High energy costs mean farmers are looking for ways to reduce irrigation costs this summer. Using newer technologies such as evapotranspiration, or ET, gauges and soil moisture sensors along with crop growth stages can help farmers achieve that, a University of Nebraska-Lincoln Extension educator says.

It costs farmers an estimated $1,000 to $2,000 each time their center pivots make a revolution in a field.

"With the high cost of energy, we need to make sure we use it efficiently in our irrigation," said Gary Zoubek, extension educator in York County. "Using these tools not only saves energy, but protects our precious water resources."

An ET gauge costs approximately $250, and soil moisture sensors and a hand-held meter or data logger costs between $300 and $500. Producers have reported the past two years that these two tools used together can save 2 to 3 inches of irrigation water per season, he said. If a pivot puts on an inch of water for each revolution, that amounts to $3,000 to $6,000 in savings.

"These tools can more than pay for themselves in the first year," Zoubek said.

Water is evaporated off leaf and soil surfaces due to current climatic conditions. The ET gauge is a way to estimate what the crop water use should be based upon the crop growth stage.

An ET gauge is a tube filled with distilled water where water evaporates through a ceramic top covered with canvas. This provides a reference ET value. Farmers are encouraged to monitor ET gauges weekly. This information along with crop stage of growth can provide an estimate of crop water use.

The ET gauge should be located in a site representative of the field conditions and can be used for irrigation management decisions for more than one field within a radius of a few miles.

Soil water sensors can be used to estimate water in the soil. Combine it with ET, soil type, crop stage and rainfall, and farmers can make informed decisions on when and how much to irrigate.

"This saves water and allows farmers to put water on at the time it is needed," Zoubek said.

For more information, visit the Nebraska Agricultural Water Management Demonstration Network Web page, http://water.unl.edu/cropswater/nawmdn

For weekly reference ET averages, visit Crop Watch's Evapotranspiration Resources, http://cropwatch.unl.edu/weather/ET_resources.html

For more information about ET and soil water sensors, visit the "Market Journal" Web page, http://marketjournal.unl.edu/, and click on the July 4 program.

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http://ianrnews.unl.edu/static/0807111.shtml

Contacts: Gary L. Zoubek, (402) 362-5508

Sandi Alswager Karstens, (402) 472-3030