The Sky's the Limit

"And that's environmentally friendly," says Brian.

"And we've saved $5,000 or $6,000 in nitrogen costs, just on corn," Don says. With their iPAQs, the Glenns use GPS the same way that the concrete companies do. Data gathered during the day -- automatically, instead of scribbled in notebooks -- is loaded into computers at sundown. Don now keeps track of how much every seed and drop of pesticide costs for every field, as well as how much the harvest brings -- and he can easily call up a P&L statement on his laptop for every field.

The Glenns even use GPS to steer the tractors with more care; because their fertilizer and herbicide applications overlap less, less is wasted. For the moment, they've managed to resist the hottest new GPS tool: tractors that steer themselves. The price is still too high, but the idea is appealing, because with an auto-steer tractor, they would be able to work at night.

Says Don: "I would hate to think I'd have to farm now without GPS." Says Brian: "We've got friends who look at all the technology and say, 'I can't afford to do it.' We can't afford not to do it."

What if the Pentagon had decided that, for the duration of the Iraqi war, it would turn off the civilian GPS signal (something that the military has never done or even suggested that it might do)? Brian just laughs. Says Don: "I'd have been on the phone right then to our senators."

Charles Fishman (cnfish@mindspring.com) is a Fast Company senior editor based at N 35? 47.234', W 78? 38.800'.