As spring planting goes into high gear in the United States, farmers are going high-tech in order to use less fertilizer, save money and protect the environment.

Satellite-based GPS navigation systems are becoming standard on modern farm equipment, helping farmers get the most from their fields.

Mixing tradition with technology

On a weedy patch of land an hour and half from Washington, D.C., farmer Brad Eustace is tilling razor-straight lines with a GPS-guided tractor. With the computer in control, he barely has to steer.

"You can do a straight line a whole lot easier," he says.

The GPS computer receives signals from earth-orbiting satellites to keep track of where his tractor is and where it has gone. Hoses deliver precise amounts of fertilizer right into the grooves that the tiller cuts.

That process prepares the field for when farmer Jimmy Messick comes back days, or even weeks later, with a GPS-guided corn planter…

"The seed goes right on top of this row. This tilled row," Messick says. "The corn planter will come back, and it will be putting the seeds exactly on top of these tilled strips that the machine previously has put the fertilizer in."

Saving money

Placing seed and fertilizer together with centimeter precision means fewer loads of fertilizer go on the fields.

"You're able to use less," Messick says. "Of course, you're saving money. And you get the same performance out of the crop."

Messick has cut amounts of one fertilizer ingredient in half. On a 600-hectare farm, he says that saves him tens of thousands of dollars.

And that's not all he's saving. Nutrients from farm fertilizers are a leading cause of water pollution.

Environmentally friendly

"If we get better at applying only what's needed, where they're needed, then that's less nutrients that can move off and get into water systems and watersheds," says Virginia Tech University farming expert Tim Mize.

Jimmy Messick also uses GPS when he sprays weed killer. Before, he says, it was easier to miss spots or overlap.

"You weren't sure what had been done, and what hadn't been done," he says. "With this system, you come back next week, next month, and you know what you sprayed and what you didn't spray."

GPS technology is guiding large-scale farm equipment across the country and some harvesters also monitor how much crop is produced in each part of a field.

"You get an idea of where the productive areas of the field are," says Virginia's Tech's Mize, "where the less productive areas are, and you fertilize accordingly."

With the price of fertilizers and fuel going up, along with the global demand for food, Mize says the name of the game today is getting the most crop with the least resources.

"Anytime you can reduce inputs and increase your bottom line, that's technology that everybody wants."

It's hands-free technology that's saving money and the environment.