IN a bid to boost production and cut costs, a new breed of farmers is using satellites and computers to guide tractors and track yields. The movement is called precision agriculture. If proven successful, the movement will change the face of farming in the United States.
At the moment, the fate of the movement rests in the hands of a few farm innovators like Gary Dau of Sheridan, Ill.
Like most Midwest farmers about to begin planting, Mr. Dau has been fertilizing his fields. Most farmers apply the same amount of nitrogen over an entire field or even their entire operation. Dau is much more selective.
By mapping the soil types within each field and inputting that data into his computer, he applies more than 200 pounds of fertilizer on land that needs it and nothing at all on land that doesn't.
Some observers believe that a widespread shift to precision agriculture is inevitable. ''We are rapidly moving toward a knowledge-based agriculture,'' says Emmett Barker, president of the Equipment Manufacturers Institute in Chicago.
Others reserve judgment. ''It's certainly getting a lot of play,'' says George Hallberg, chief of environmental research at the University of Iowa in Iowa City. But ''I'm not holding my breath for it to solve a lot of problems for us.''
Varying the amount of fertilizer for each section of his field would be hard to do manually. But Dau does it automatically with a satellite technology called the global positioning system or GPS. A GPS receiver mounted on his tractor lets him pinpoint his location to within a few feet. By tying the receiver into his onboard computer, he can tell what soil type he's fertilizing. When the computer determines the tractor is moving onto a new soil type, it sends a signal to the sprayer to vary the nitrogen.
That's just the beginning. By mounting the same receiver on a combine and adding an automatic yield monitor, farmers are getting a much better picture not only of what they're putting into the land but what they're getting out of it. ''It's not inconceivable that you will plant four different varieties [of seed] not only within the same field but within the same row,'' says Mr. Barker. ''There's no way that this is not going to change the way we farm.''
Ken Hofer of DeWitt, Iowa, thought he used the wrong seed types last year on part of a 60-acre cornfield. But when he began studying the section with his satellite-generated computer maps, he came to a much different conclusion. The seed varieties worked just fine in areas where he had previously planted soybeans and ''knifed in'' his nitrogen. In those areas where he had previously planted corn and applied nitrogen fertilizer only on the soil surface, yields were poor.
''I didn't think it was going to pay for itself,'' says Mr. Hofer of the technology. But ''it's telling us something we never imagined.'' Had he prepared that field correctly, he estimates he could have boosted production and gotten at least $2,000 more from that field alone.
The benefits vary widely. Dau is skeptical precision agriculture will boost yields but he says he's saving $4,800 a year by cutting his use of nitrogen. That savings should cover his $15,000 cost for the equipment in less than four years, he adds. Ted Macy, who quit farming to create an agriculture software firm called Applications Mapping Inc., has documented an average savings of $14 per acre on a large Indiana farm because precision-farming techniques used fewer seeds and chemicals.
BECAUSE it can reduce inputs, the movement is getting attention from environmentalists. ''It can have some benefits,'' says Chuck Hassebrook, leader of the stewardship and technology program at the Center for Rural Affairs in Walthill, Neb. ''The downside is that it can be costly and, depending on how the technology actually evolves, ... it could be one of those things that favors the larger producer at the expense of the family farmer.''
Environmentalists also doubt precision agriculture can replace other earth-friendly techniques commonly known as sustainable agriculture. ''It's easy to get enamored with technological solutions,'' says Dr. Hallberg of the University of Iowa. The breakthrough with precision agriculture may not be the technology itself but its emphasis on precise record-keeping that leads to better management, he says.
The precision-farming movement is still small. ''We are still in the innovator stage,'' says Warren Clark, a West Dundee, Ill., agricultural consultant who tracks some 90,000 computer-using farmers.
An estimated 600 farmers bought yield monitors last year, a key device in tracking farm output. Many are just starting to use the technology to determine their yields. A slightly smaller group has tied into the GPS system to do field mapping. And an even smaller group has tied everything together -- from mapping seed counts, fertilizer and pesticide use to capturing yield information by geographical coordinates.
''I can make a dozen phone calls and give you the 25 or fewer people who are using it ... from A to Z,'' Mr. Clark says. ''But that's going to change.''
Interest is already building. Ag Leader Technology, the leading producer of yield monitors, ran out of inventory last year because demand was so large. Deere & Company, the world's largest manufacturer of farm equipment, is offering its first precision-farming system this fall for combines and will offer the equipment nationwide next spring.
Last week, the six-month-old Ag Electronics Association announced it was forming a group to propose standards for agriculture-data interchange. That way, companies can build standard yield monitors and other electronic devices that will plug into every manfacturers' equipment.
''This is going to take several years,'' says Ken Hilton, president of FMS/Harvest, an agricultural software company in New Lenox, Ill. But ''once all that information is available, it's going to be incredible.''
''Precision farming is not a fad,'' adds Chuck Studer, manager of Deere's precision farming group. ''It will be an integral part of successful farming operations certainly by the end of the century.''