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CORVALLIS -An Oregon State University professor has found a way to stop the stink in manure ponds by using the stuff of tennis shoes.

Ron Miner, a professor of bioengineering at OSU, has spent much of his career developing effective ways to manage farmyard manure, and sniffing out the offenders. Part of his work focuses on how to stop the smell of hog, dairy and chicken production from intruding on the neighbors.

Now Miner has found the perfect odor-eater in tennis shoes.

Miner's design is a pond cover made of bits of bright colored polyethylene foam that are left over from the manufacture of products including athletic shoes. The two-inch thick mat is light, porous, and full of the stuff of athletic legends...air.

The sponge-like cover creates an airy home for oxygen-loving bacteria and other creatures that gobble up ammonia and similar odor-causing compounds.

"It works just like the soil over your drain field that makes it possible to picnic on top of the septic tank," explained Miner.

Miner and his colleagues from North Carolina State University field-tested the mat on an established - and stinky - one-acre hog manure pond in North Carolina. Within a few weeks after installing the mat, Miner's team measured an 80 percent reduction in ammonia emissions in the air over the pond. A trained panel of odor experts from Duke University proclaimed very low odor and irritation concentrations wafting from the newly covered pond.

Liquid manure storage ponds are widely used to store livestock and poultry waste. The gases released from manure ponds have been linked to problems such as acid rain and global warming. But Miner's concern goes beyond measuring the gas level in laboratory samples. His concern is for people - how does barnyard odor affect the neighbors?

"Studying odor is more than empirical research," Miner said. "It is a mix of science and emotion. People don't react to odors in an objective, rational way. The whole perfume industry is based on the emotion elicited by odor."

So the question of how bad a manure pond smells is not purely objective, according to Miner. It may elicit anger from people who feel they have no control over where the manure pond is built, or when the stench will intrude into their own homes and lives.

As more people move to the country, more conflicts arise downwind.

The problem of farmyard odor is widespread and increasing, as the animal production industry moves more animals into smaller spaces. For example, since 1968 the number of hog farms has dropped from about a million to about 200,000, but the number of pigs has held steady at about 60 million.

"That's a whole lot of manure," said Miner.

After successfully field-testing the odor-eating pond cover, Miner and his students at OSU are now experimenting with barn ventilation filters made of the same recycled shoe bits.