A technology developed on the University of Georgia campus in Tifton, Ga., that helps farmers improve yields and conserve water just got easier for farmers to use, says a UGA irrigation specialist.

In southwest Georgia, the hub of irrigation use in the state, more than 6,000 center pivots are used to water crops like peanuts, cotton and corn.

But farmers don't have much control over how much water the irrigation nozzles spray as they pass over fields. Even small fields can vary widely in topography and soil types, with some places wetter or drier than other places in the same field.

Variable-rate irrigation takes all of this into consideration, says Calvin Perry, an agricultural engineer with the UGA College of Agricultural and Environmental Sciences who helped develop VRI. Researchers with the UGA National Environmentally Sound Production Agriculture Laboratory in Tifton introduced VRI to farmers in 2001. It became commercially available in 2004.

The concept is simple: Apply water when and where crops need it. Don't apply it where they don't. VRI technology uses computer maps, global positioning systems, soil sensors and software to control where and how much water the nozzles on a center pivot spray on crops.