"In 1994 we were growing only soybeans in that field. When I checked the records from 1993, when we were growing corn, I didn't see the same variation. I knew in '92 we had planted soybeans in most of the field, but oats on that end," Harford says, pointing to the region that was glowing emerald in the 1994 data set. "So it looked as if we had a parasite that ate soybeans but not corn or oats -- and that could survive one year without food but not two." He hired a soil-testing company to probe for microscopic wildlife. (When the researchers arrived, Harford used the data from his yield monitor to plan the pattern of their sampling sites.)
He found he had an infestation of a soybean-loving nematode that until then had been encountered mostly in the South but was known to be moving north. "This was the first time we'd seen it on that scale, distributed through a whole field like that," he says. Alerted by the monitor, Harford looked for and found the parasite in several other fields. Now he's considering his next step. He might use nematode-resistant seeds or try starving the parasite out by growing corn two years in a row, skipping the rotation with soybeans. Both alternatives have short-term disadvantages, but the evidence from the yield monitor is that the fight is well worth making.
On the other hand, sometimes the monitor makes problems go away. "I lease some of my acreage," Harford says. "Recently, I was driving through a field with its owner. We reached a section where the drainage was deteriorated a bit. The plants looked short and ugly, and partly because of that, we decided to upgrade the system.
"That would have meant replacing 8-inch-diameter pipe with 15-inch-diameter pipe and running the new size through fields belonging to three other people. The process would have been complicated and expensive." So before Harford went ahead, he checked the field on the monitor. "I found that we were losing only about $1,500 of yield in that region -- and $1,500 wouldn't even have paid for the interest on the investment needed to do all that work." The ugliness of the plants had been deceptive. "We used to fix things like that," he says.
Harford is still thinking about some of the information he's gathered. "What ought to be our best soils actually turn out to have the lowest yields. Maybe that's because the most crop has been taken out of the best soils." If he settles on that hypothesis, he might add more fertilizer to the very soils that are supposed to need it least. (Currently, the same amount of fertilizer is added to low- and high-yielding fields.) Yet his data -- which he quickly points out are very limited -- don't support any direct relationship between productivity and fertilizer distribution. "That's interesting," he says, shaking his head. "That sure isn't what the fertilizer companies tell you."
Harford expects yield monitoring to play a big role in his technology management. Every year, the seed, machinery, and chemical companies pump a small river of studies through Harford's fax machine, all showing the handsome increases in productivity awaiting any farmer canny enough to buy their products. "They always seem to claim to give you about 6 bushels an acre more [corn]," he says. "Does this mean that if I bought everything, I'd grow 300 bushels an acre?" (Even 200 bushels would make an excellent year.) "I doubt it."
Harford knows that just because a product did something heroic 150 miles to the south last year doesn't mean it will do anything on his farm this year. It might never grow the six extra bushels in his particular region to begin with, and even if it does, unrelated factors might depress production by six bushels, preventing him from noticing the improvement. The only dependable way to evaluate a technology is to "amplify" the signal over time by using it on the same fields for many years running, but that necessarily retards the rate of innovation. Harford tries to stay up-to-date with new seeds -- he has 12 varieties in his fields this year, the oldest all of four years old -- but he suspects sometimes that his decisions are really driven by vendors. "We have our complaint of the month," he says. "The salesmen all sell to that."
A farmer armed with a yield monitor is not such an easy target. "We've always had to take other people's data, gathered from other people's fields," Harford says. "Now we have our own data, gathered from our own fields. If a seed salesman promises me six bushels and his seed doesn't deliver, I'll know in a year. And so will he. To a farmer, validation is power."
Only 200 farmers used the yield monitor with the GPS package for the 1994 harvest, but Harford is sure the device will spread quickly because the effect on revenues is so great. (Myers says his sales have quadrupled this year, and John Deere, a farm-machinery and equipment manufacturer headquartered in Moline, Ill., has announced plans for a combine that will come with yield monitoring built in.) Moreover, the technology will only get more powerful, as on-the-fly testers are developed to measure different soil properties (nitrogen, pH, phosphates) continuously and as equipment appears that can handle each field unit separately -- for example, matching the right seed to the right soil or applying quantities of fertilizer or chemicals that are specific to each unit. Perhaps in the near future, farmers will be yielding two "crops": one measured in bushels -- and the data itself, measured in bits.
The implications for agriculture are profound. Leading-edge farmers will likely become far more experimental because they will be able to prove theories and put them into practice very quickly. Harford expects farm size to grow significantly -- and yield monitoring to make it possible to handle far more variables than in the past. Farms already have been growing, from a national average of about 350 acres in 1967 to 500 acres in 1994, but Harford says he wouldn't be surprised to see consolidation proceed much faster over the next 20 years.
On a deeper level, Harford suspects yield monitoring might help change the basic paradigm of farming to one in which farmers adapt to the soil instead of forcing the soil to adapt to them. He makes his point by pulling out a map: "We have these drainage pipes running under the fields. Sometimes the soil settles down between them, making parallel rills. They're annoying to run over, so last year I trimmed them down. And yield went down. Right there."
That was not a big surprise to Harford; he likes to point out that corn did not evolve in a world in which the ground was being plowed up every year. He thinks soil is more usefully seen as a biological tissue, organized around common systems and networks of exchange and circulation, than an inorganic commodity that can be torn up and ripped apart. But the issue has caused some debate among farmers. Now Harford has the numbers.
Every technology has its dark side, and yield monitoring also raises the possibility that crop farming might end up where poultry farming is now: so rationalized and controlled that it can be done by 9-to-5 corporate employees or even by robots. That won't necessarily happen, but it's possible that Harford has picked up a tool that eventually will leave no room in agriculture for a person of his skills and intelligence. It's a gamble; it's an unknown; but, of course, if Harford were afraid of unknowns, he would never have become a farmer in the first place.
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Fred Hapgood (fhapgood@world.std.com) is a freelance writer based in Boston.
