WILL SEBERGER/Arizona Daily Wildcat Donald Post, a soil, water and environmental sciences professor, examines dirt samples in his lab March 1. Last semester was Post's final semester teaching at the UA.

Donald F. Post, self-declared Ohio farm boy known for his big, tooth-filled grin that spans ear to ear, has a knack for getting students excited about soils.

For 37 years, Post brought his enthusiasm for soils science into the classroom at the UA. Four and a half years ago, he became a professor emeritus. Although retired, he continued to teach part time.

Post drove across the country to join the small department of agriculture chemistry and soils in 1967. The program, thanks to his efforts, has since evolved into the soil, water and environmental sciences department.

"I wanted to teach. As far as I was concerned, it was the best place in the country," Post said.

And teach he did. Over the course of his tenure, he instructed more than 5,000 students.

"Many people who had (Post's) class 10, 20, 30 years ago come up to me and ask how he's doing. He has made a big impact on people across the state," said Tom Thompson, a full time soil, water and environmental science professor.

For someone who loves soils, Post developed a simple teaching philosophy.

"If the student left with just as much or more enthusiasm for soils than when they come into class, I thought I was successful," Post said. "The classroom was hands-on; I believe you learn by doing."

Students in his soil morphology class were often expected to classify up to 20 different soils in a couple of hours. Soils are defined by properties such as color, stickiness, plasticity and texture.

Texturing involves estimating the composition by rubbing moist soil in the palm of the hand. Different sizes of rock fragments, with sand as the coarsest and clay the finest, affect the uses of soils from road construction to agriculture.

"He is a wealth of knowledge. He is fun. He is a great teacher who is patient and caring," said Emily McKindley, a SWES junior.

Post knew his passion for soils would spark student interest.

"My responsibility was to keep enthusiastic. It is up to the instructors to keep the students open-minded and to make it fun," Post said.

One of his favorite jokes involved making the word "dirt" taboo in the department. The d-word was as dirty as any swear word.

"I told my students, 'Don't call me a dirt scientist,'" Post said. "Dirt is soil out of place. Soil is a natural part of the environment."

Colleagues had much to say at Post's retirement dinner Thursday.

"There are three things that come to mind when I think of him: warmth, family and education," said Ian Pepper, a SWES professor."

"It would be a real trip to peek into his classroom because he'd be in there making the kids enjoy soils," Pepper said. "He'd be in there bouncing off the walls, playing with little piles of dirt, making soil ribbons, eating dirt."

"(Post) is one of the most outstanding professors we've had at our department and at the university," said Jeffrey Silvertooth, SWES department head.

Post initiated and ran the UA Soil Judging Team in 1968 and is still partially involved.

"The soil judging has been a love of mine," Post said. The team, whose members jump in soil pits to classify soils, competes against other universities nationwide.

"It has been an honor to work with Dr. Post," said Sanjai Parikh, a SWES graduate student who now helps coach the team with another graduate student. "Seeing how important it is to Post ... he finds it so important to make sure students know soil basics."

He is also responsible for building the membership of Alpha Zeta, the agriculture college honorary.

Since Post became more involved in the honorary, its membership has climbed to more than 30, said Todd Rovey, an agronomy and field crop management junior.

Although he's now officially retired, Post, who gets to keep his office, says he'll still be around, completing a few projects.

"I'll still show up, even though I have no responsibility," Post said. "Once you decide you've accomplished everything, you're in trouble."