AUTOMATION CROPS UP HERE

Mechanical Engineering, Jun 2005 by Thilmany, Jean

Clay Mitchell runs the family business from his office on wheels. It's not what you're thinking. Mitchell doesn't work the cell phone while driving between meetings.

He conducts business from the tractor cab: sending e-mails, returning telephone calls, monitoring and controlling the programmable logic controllers that operate the grain handling and storage facilities.

Mitchell and his father, Wade, operate an almost fully automated farm outside Waterloo, Iowa. The tractors steer themselves, the smart sprayer knows when to turn its nozzles on and off, the Internet is piped into the cabs, and the grain-handling facility can be controlled from anywhere on the farm network.

"The Mitchells are among the most progressive farmers in the country," said Tony Grift, an agricultural and biological engineer at the University of Illinois at Urbana-Champaign. "They're showing what forms of automation actually work reliably on the farm."

This year, clay Mitchell has unveiled the innovation that ties together all the technologies-the thing he's been aiming for since bringing in autosteering five years ago.

Last year, by using technology to plant fields with a mix of corn and soybeans, Mitchell was able to boost his crop yield by 20 to 30 percent. The mixed crops-one short, one tall-make ultimate use of sunlight for higher yields.

Now he's ready to talk about it.

"That's a pretty big deal," Mitchell said. "It has significant environmental and economic impacts.

"Yields over cropping them separately are much higher and we're not adding anything else," he added. "In today's intensive farming, even getting 1 or 2 percent yield increase is hard."

Autosteering makes Mitchell's mixed crops possible.

"To generalize, here on our farm, we've used survey-quality global positioning to automate machine controls," Mitchell said.

Many farmers now commonly use GPS to manage large holdings. But survey-quality GPS is accurate down to the inch and it updates at a rate of 50 times a second. Mitchell feeds that position information to automatic steering controls.

"We can then do things much more accurately than people ever could," he said.

The precisely controlled tractors apply fertilizer and chemicals in a tight band around the seed. That precision application has cut nitrogen use at the farm by 30 to 40 percent and pesticide use by 20 percent.

"So that was a pretty big benefit," Mitchell said. "What's another really big step forward is we're using essentially a new cropping system allowed by these new technologies."

The smaller soybean plants need less sunlight for photosynthesis. Interseeding allows Mitchell to partition the sunlight among the plants for higher yields of both crops than if they'd been planted separately.

Farmers in the developing world commonly plant two crops in the same field, but they plant by hand. The practice has never been used on a mechanized farm, as far as Mitchell and Grift, the University of Illinois engineer, know.

"There's a lot of drawbacks to mechanized ag," Mitchell said. "For the first time, we've turned the corner where we can use these technologies to bring back some of the ancient practices that have kind of been lost."

JEAN THILMANY