Touch probe system Yield monitor technology is now being used even for hand-harvested vegetable and fruit crops. A touch probe system lets Bobby Ham, Snow Hill, N.C., identify individual workers and tell how much they've picked.

"Our payroll is instantly complete. We take that little hand probe back to the office and we're through. It tells the date and time every bucket is put in that wagon," Ham said at the recent Southeast Vegetable and Fruit/AgTech 2000 Expo in Greensboro, N.C.

Ham has as many as five probes working fields simultaneously, operated by foremen. The foremen can wear small GPS receivers to give field position data to help track yields.

"Back in the office, you can merge the pick data with the time data from the GPS and that gives you yield information. You can match that up with the mechanical yield maps," Ham says.

Simplifying economics help streamline the operation during the hectic harvest season. "The probe tells you what you've spent each day for each crop," he says.

North Carolina State University scientists observed how the probes performed under real field conditions. "Bobby feels justified in the expense just with the payroll aspects. We've added low-cost hand-held GPS receivers, which you can buy for under $200. You can record that field data on palm computers. It shows a good bit of promise. We're going to take a look at expanding the capability of yield mapping with hand-harvested crops," says Gary Roberson, NCSU agricultural machinery specialist.

Ham says the savings realized by using the hand probes paid for the new system in a couple of months of harvesting. "I'd say you need 50 to 60 workers on the farm to justify this system," he says.