Engineering at Nebraska Fall09
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Doing what the plants tell us


Some countries use three times as much nitrogen as needed to fertilize crops, evidenced in river estuary "dead zones" and groundwater contamination. John Solie's work on agricultural sensors enhances fertilizer application accuracy, reduces waste to benefit the environment, and saves farmers money.

Solie, who holds a 1982 interdisciplinary Ph.D. in Mechanical & Agricultural Engineering from UNL, was born in Wisconsin where his father studied economics and law on the GI Bill. Solie spent summers at his grandparents’ farm in southeast Nebraska. His grandfather, who attended UNL for dairy science studies in the early 1900s, first brought Solie to East Campus when "I was a high school student who liked to build things."

Solie’s family moved to Washington, D.C., where his father worked for the Central Intelligence Agency, and Solie attended the University of Maryland, earning a B.S. degree in agricultural engineering. But Solie became "tired of engineering and then attended Creighton University’s law school while working on the family farm in Brownville."

Field Walker"I didn’t have the business approach to be a successful farmer, and I didn’t have the personality to be a lawyer," Solie recalled. "But I liked research and campus life and decided to pursue an advanced degree."

Green SeekerSolie likes the idea of his career path as a "bridge" and sees similarity between his pursuits in engineering and law. "Both teach you how to solve problems when you don’t have all the information," Solie said, "with each in its own way helping people to fill gaps and draw conclusions."

"I always walk in two different worlds," Solie said—whether connecting people and processes, academia and acreages, and even (within engineering) mechanical and agricultural disciplines. These varied perspectives helped Solie form a vision and team that has brought success: in his career as a Regents professor with Oklahoma State University and with the innovation resulting from his research group, the Variable Rate Technology

Solie returned to UNL for Masters’ Week 2009 and visited several East Campus classes. His advice for today’s engineering students is:

1. Jobs are there, you just have to
work harder to find them.

2. Don’t be afraid to move (you can’t always achieve your goals inside your home state).

3. Get experience outside the academic world to make yourself more employable.

Team. Together they developed the GreenSeeker sensor: a variable rate fertilizer application system that’s now making a difference at farms around the world.

The Greenseeker uses active optical light sensors to look at a growing crop and, by evaluating the amount of light reflected at red and infrared frequencies, assesses the amount of fertilizer optimal for the yield potential of the plant. Like Solie, this device straddles the worlds of engineering and science.

With field testing and refinements throughout the 1990s, the innovation developed into a 60-foot-wide farm implement that applies targeted fertilizer at 15 miles per hour and included 65 onboard computers (a bit "intimidating to average farmers, but the device never had a system failure," Solie said). Recent iterations of the digital version have evolved toward a handheld unit that’s more readily accessible for third world countries—still assessing the plants’ yield potential and applying algorithms that guide fertilizer application—with acceptance in a number of countries including China, Australia, Argentina and Mexico.

Solie said he’s especially proud that Greenseeker use was endorsed by the late Norman Borlaug, the Nobel Prize winner for agriculture who advanced the "green revolution'' for combating world hunger. With this device, Solie has once again spanned perspectives, with a micro-level solution to a macro-based problem.

- Carole Wilbeck

Nitrogen Map

in a 2009 UNL Masters' Week presentation to students, John Solie demonstrates the size of future sensor devices such as the Greenseeker--now available as a handheld device, shown above. The Greenseeker can be used by an individual farm worker, or connected to a mechanized system (top right), to determine and apply the proper amount of fertilizer for a crop's conditions. Reducing harmful effluent from over-fertilization of crops, shown in satellite images, is an important benefit of applying sensor technology such as the Greenseeker.