While farmers rely largely on experience and careful guesswork, many are beginning to practice what has come to be known as precision agriculture: the use of technology to cope with the variables that jeopardize their crops.
Farmers who may have blanketed entire fields with uniform sprays of of fertilizers or pesticides a few years ago may today use soil and crop analyses linked to precise location data to deliver just the right amount of chemicals in just the right spots. And farmers can now use digital yield monitors attached to their combines to track the performance of a field, practically row by row.
Much of precision agriculture technology relies on Global Positioning System devices and software that links information about weather patterns, soil properties and pest management to points on a map. That information is used to direct variable-rate applicators that can tailor the amount of fertilizer or pesticide needed in each part of a field. The technology has been most widely adopted in the Midwest for sugar beets, corn and soybeans.
Cost inhibits change
Farmers who employ precision agriculture say the methods give them new ways to analyze the relationship between what they put into the soil and what they get out of it and allow them to manage more acres for the same cost. But adoption has been slow, largely because of the cost of equipment and services, an expense that can be prohibitive for small farms, and because the benefits are not always clear-cut.
"Producers of wheat in the Dakotas and Montana are finding it really difficult to make any profit with the price of wheat in the world market," said Pierre Robert, director of the Precision Agriculture Center at the University of Minnesota. "If you don't make any profit, you don't have the extra change to practice and invest in new techniques."
Another problem is that it can be frustrating and intimidating to try to make different kinds of farm software and GPS data formats work together.
"Most farmers do not want to spend hours and hours in front of a computer," said John Reifsteck, who runs an 1,800-acre corn and soybean farm in Champaign, Ill. "You can get very frustrated when all you want to do is print a nice map and things don't work that well."
"There's a 10-40-50 rule," said Steven Sonka, a professor of agricultural management at the University of Illinois at Urbana-Champaign. "Ten percent are using variable rate application and yield monitors because it's interesting to them and it seems like a good thing to do. Forty percent are watching and will start using them as soon as they're convinced it's economical. Then there are the 50 percent of farmers who are waiting to retire and not have to worry about all of this."
Most buyers in the agriculture industry agree that the components of precision agriculture are necessary for success. "The people who are resistant to precision methods aren't surviving," said Thomas Facer, vice president for agricultural services at Agrilink Foods, a food cooperative based in Rochester, N.Y.
One farmer who is using precision methods is Ken Mattingly, owner of M-B Farms in LeRoy, N.Y., about 50 miles southwest of Rochester. Before planting sweet corn on 900 of his 2,000 acres, Mattingly hired Agricultural Consulting Services, a crop consultant company based in Rochester, to analyze the soil in different parts of his field and decide how much fertilizer the different parts needed.
During the year, the consulting company had sent Richard Wildman to take 400 soil samples in Mattingly's field, one sample for each four- or five-acre section. The soil samples were analyzed for about 15 components, including concentrations of calcium, phosphate and nitrogen. Wildman then compared the soil analyses with yield maps based on the previous year's harvest.
Early one morning last month, Mattingly was at the field with Wildman and Mike Belmore, a spray rig operator with J.D. Buckley & Son, a fertilizer and pesticide company in Stafford, N.Y. Hunched over the side of a truck, the three men pored over a digitized field map prepared by Wildman to show where phosphate and nitrogen would be sprayed at high, medium and low rates.
That map was also loaded into a computer inside the spreader tractor, a tall vehicle loaded with fertilizer tanks; the computer was hooked up to a GPS unit. Two 15-foot booms on either side of the tractor were lined with nozzles about every 30 inches. A controller in the tractor linked the fertilizer map to the nozzles, controlling the application rates and alternating fertilizer types as the tractor moved from one part of the field to another.
Throughout the day, Belmore, who spreads fertilizer across as much as 520 acres a day, navigated the tractor based on the GPS coordinates on his screen, which told him where he was in the field.
Later in the week, Mattingly drove a planter tractor to spread the seeds across the field. And then a few weeks into the planting season, Belmore returned to apply herbicides to any weedy areas and spray pesticides to protect the crop against corn borers and other pests. Farm consultants can look at aerial images and see signs of pest damage, then apply pesticides where they are needed.
"We're all looking for the optimums," Mattingly said, "and we don't want to waste money on the chemicals. It costs me money to hire these guys, but I think I'm doing a better job."
Mattingly said he was spreading fertilizer more carefully and using fewer pesticides than he did a few years ago because of the variable-rate applicators. But he said it was still too early to tell what effect that would have on his crop yield.
'So many variables'
"There are so many variables that enter into what a crop yields that it's hard to tell yet whether this is making a difference," he said. "I think it will be four or five years before we can judge."
After a field has been fertilized and planted, farmers and crop consultants can use satellite and aerial imagery to monitor their crops each week or month. The images are particularly helpful for large farms, where it is difficult for the farmer to monitor different areas of the field from the ground.
"Large farms need the ability to know what is going on across the range of their acres, remotely," said Wildman, the agricultural consultant. "It's impractical for that one manager to go out and check all those fields. They physically cannot do it."
The satellite images used by farmers come from Landsat, the system of land-observing satellites operated by the federal government. The satellites take infrared photographs from about 20,000 feet above Earth; each pixel represents a little more than 5 to 10 square yards on the ground. The infrared camera can detect a field's heat and moisture levels. These images can be overlaid onto farm mapping programs to show areas of drought or flooding. Such images cost the farmer $2 to $3 per acre.
But if a farmer commissions Landsat to take an image of a farm when there are clouds blocking the view, the farmer is out of luck and still has to pay the bill. And satellite images are less useful for small farms because the image resolutions are so low.
Aerial infrared photography costs $5 to $6 per acre, but it offers slightly better resolutions without the same risks of clouds. Zeke Hurd, a pilot based in Rochester, charges about $200 an hour to fly a small aircraft at low elevations to take infrared photographs of farmland. The plane can fly as slowly as 40 miles per hour, allowing Hurd's Hasselblad digital infrared camera to take images that have a resolution of about 6 square inches per pixel. A GPS unit on top of the camera links every shot that is taken to a geographic spot.
"If there's an alteration in the moisture levels," Hurd said, "you won't be able to see it with the naked eye, but the infrared will pick up the reflection. An image might illustrate a need for irrigation in a specific area."