"This profit map shows a farmer the bottom line," said Calvin Perry, a research engineer with the UGA College of Agricultural and Environmental Sciences.

"Other maps can show where problems are," Perry said. "But when he can see what he put into his pockets -- how much profit he made on that land -- he can begin making his operation more efficient."

Perry studies precision farming at the Coastal Plain Experiment Station on the CAES Tifton campus. George Vellidis, Jeffrey Durrence and Dan Thomas, all engineers, are part of the large team working to develop, perfect and test precision farming equipment, software and methods.

Profit maps and yield maps show farmers short-term and long-term issues they must face and manage to become and stay profitable, Thomas said.

Farmers use Global Positioning System satellites to map soil types, disease or insect problems, nutrient and water applications, yields and, finally, profit.

The maps show the yield or profit for every part of a field, Thomas said.

Special sensors attached to harvesters fitted with GPS locators gather the information. Computer software links the yield data with specific spots in the fields. The farmers then use other software to create the maps.

"Yield mapping is a key component of precision farming," Vellidis said. "It allows farmers to see the results of their management practices."

Vellidis said all those maps make management more intense. They make farming more complicated and simpler at the same time.

"So many factors affect the crop yield it's hard to say 'this one will make the change,'" he said. "But you can't even try to make that decision without accurate information."

Vellidis said yield maps show the farmer vividly where he could make management changes to boost profits.

"That's really important for us now, as we're looking ahead and wondering if price support programs will be there much longer," he said.

Thomas said precision farming helps farmers be better stewards of the environment. "If you put out only the pesticides and nutrients you need, and only where they're needed, you reduce the risk of overapplying chemicals and environmental pollution," he said.

But not many farmers are using precision farming methods yet.

"It's not cheap," Durrence said. "It's hard to get into it a little bit at a time. And not many commercial services are available yet."

Durrence figures on a start-up cost of $12,000 in equipment, including the yield monitor, computer, printer, GPS equipment and a subscription to a service that make the GPS system more accurate.

Much of the precision farming technology was first developed for farmers growing corn and other grains in the Midwest.

"We started working to adapt that technology to cotton and peanuts," Vellidis said. "We ended up almost starting over to get a yield monitor that works for our crops."

Vellidis said five farmers -- four in Georgia and one in Texas -- are planning to use the peanut yield monitoring system this year. He hopes the equipment will be on the market for the 1999 season.

The team's work with cotton yield monitoring isn't that far along. But they expect good results soon. Two cotton yield monitors are on the market. But UGA testing shows they need some modifications to be accurate in Georgia growing conditions.

"This is a high-tech approach to farming -- a real information revolution on the farm," Perry said. "It's not easy to spot, except for the GPS antenna, from the highway. It's exciting for us to see Georgia farmers on the cutting edge of this technology in the Southeast."