In 1900, peanut farmers plodding in mules' tracks had a good idea what a particular spot of ground needed. In 2000, riding monstrous machines with computers and satellite receivers, they'll know that spot's needs even better.

"As the scale of agricultural machinery grew in the 20th century, our farmers lost the ability to address the specific needs of areas within fields," said University of Georgia scientist George Vellidis. "This system gives it back."

Vellidis, an associate professor of biological and agricultural engineering with the UGA College of Agricultural and Environmental Sciences, is among the scientists who developed a peanut yield-monitoring system.

Precision picker mechanism

The system should be in use next season. It uses small computers and load cells to weigh the picking basket and Global Positioning System receivers and special software to map fields.

The yield monitor relies on GPS to precisely fix a starting position. Every second the harvester moves across the field, load cells under each corner of the picker basket send weight data to the computer.

The computer records the harvest and GPS position data together. It knows, for instance, there were 2,000 pounds of peanuts in the basket at a precise spot and 2,500 pounds 10 feet later.

With that data, farmers can use spreadsheet software to map yields, diseases, profits or fertility anywhere in their fields.

Idea borrowed from Midwest, refined for Georgia fields

In fall 1994, an engineering team at the CAES Coastal Plain Experiment Station first tried to weigh peanuts as the mechanical combine picked them. They tried unsuccessfully to adapt equipment already in use in Midwestern grain fields.

"That was really a concept year," Vellidis said. "We put together some load cells and data-recording equipment just a week or two before harvest started. We were looking, at that point, to see if the idea was even worth pursuing for peanuts."

It has been.

Accuracy within 1 percent

The biggest problem the engineers overcame was recording accurate weight data from a 17,000-pound mechanical combine being pulled by a tractor over rough fields.

They solved it with software that takes raw data from the load cells and filters out the machine vibration, electronic noise and travel roughness to record only the usable, accurate, weight data.

"This system is accurate to within 1 percent over an entire field," Vellidis said. "That rivals or surpasses the most accurate systems available for other crops."

Some farmers rely on the system's precision to learn where their fields are profitable and where they may be better off not planting. Others use it to compare management practices.

The system enables farmers to manage land for peak profits. It tells them where they need pesticides or fertilizers, so they don't have to just blanket the field. In that way, the plan helps protect the environment, too.

Potential realized in four years

Many people quickly saw the system's potential for Georgia and Southeastern peanut farmers. The Georgia Peanut Commission and Georgia Research Alliance provided funding. Albany Scale and Kelley Manufacturing of Tifton gave equipment and technical support.

With that help, the engineers took the project from a concept to a field-tested unit in just four years.

In the next two years, eight Georgia farmers and researchers at Auburn and Texas A&M used the yield monitors and suggested refinements. During the testing, they mapped more than 1,800 acres of peanut fields.

The UGA scientists who developed and refined the peanut yield monitor applied for a U.S. patent in 1998. They expect it to be granted in early 2000.

The system attracted the WAG Corporation of Tupelo, Miss. In 1999, UGA signed a licensing agreement with WAG, which plans to have the system on the market for the 2000 harvest season.

"We partnered with growers and the industry to develop the product and expect it to be commercially available soon," Vellidis said. "We've met the need of our constituents."