Tonka, Jana and Edie have a big, smelly secret.

Every morning, the three resident African Elephants at the Knoxville Zoo plod into the Stokely African Elephant Preserve to begin a long day of eating. Vegetarians, they’ll each consume nearly 500 pounds of hay and other plant material over the course of the day. Zoo visitors will ogle their majestic trunks and giggle at their swaying dance moves – a mechanism they use to cope with captivity – and some lucky patrons will even see the elephants deposit their excess waste around the enclosure.

But only one man will see what happens next.

Robert Hodge has been working at the Knoxville Botanical Gardens for a little more than a year. Having earned five years of urban agriculture experience in Knoxville, the quick-talking gardener joined the Botanical Gardens with an elephantine ambition – develop a community garden in a corner of the 47 acres of carefully cultivated green space.

He had accomplished a similar goal at the first community garden he helped organize, a site that he describes as “river bottom land.” The project taught Hodge a new appreciation for rich, nutritious soil, and when he embarked on his second community garden in Lawnsdale, he knew he needed some kind of fertilizer to prepare the dirt.

Hodge went to Beardsley Community Farm, a local non-profit run by AmeriCorps volunteers, to see how they started their gardens in the nitrogen-deficient soil. There, the staff let Hodge in on a scruffy little – big – secret.

“To get the nitrogen of manure, inside the city limit, is a challenge,” he said. “There’s no livestock, so what do you do? You go to the zoo.”

That’s exactly what he did, and that’s exactly what he’s doing.

“We call it zoo poo,” he laughed. “Maybe zoo manure – that’s slightly less juvenile.”

After the visitors have left the zoo, someone has to clean up the elephants’ mess. And it’s not just elephants – bovine (vegetarian) animals such as zebras and camels also leave sizable duties to be carried out. Typically, the zoo uses a third party waste removal contractor to remove the waste and cart it off to a landfill, a process that can cost thousands of dollars and waste valuable resources.

But why throw it away when you can use it?

According to Shawn Hawkins, a professor of biosystems engineering and soil science at the University of Tennessee, bovine manure is “extremely valuable.”

“It has all the plant nutrients that you would expect,” Hawkins said, “because that’s all they eat.”

Generally speaking, Hawkins said manure has three vital nutrients that most plants need to grow – phosphorus, potassium and nitrogen. This last nutrient can be hard to come by for plants. Even though nitrogen is the most prevalent element in the atmosphere, plant life requires a more reduced form, such as ammonia or nitrate, in order to generate new organic matter. That’s where Tonka, Jana and Edie come in – a portion of the nitrogen in the organic matter of their daily diet passes through their guts and ends up in the manure.

A circle of life has no beginning or ending, but in Knoxville, the elephants seem to be the start of a complex chain of events. Hodge said he received 120,000 pounds of zoo poo last fall, and plans to obtain that same amount over the next few weeks. He will leave it to decompose into the soil, and by May, Hodge said many of the nutrients will have been absorbed into the earth, priming it for cultivation.

It’s a win-win for Knoxville; the zoo would normally have to pay for the landfill dump, but the Botanical Garden takes the zoo poo gladly, for free.

“It’s a wonderful compost granola bar,” he said, laughing.

So wonderful, in fact, that the zoo requested this story not published. According to Phil Colclough, the director of animal collections and conservation at the Knoxville Zoo, public knowledge of zoo poo and its powers would generate a storm of requests from private citizens for private use. The Botanical Gardens must sign a waiver acknowledging that they are taking untreated manure to procure it, and Colclough is not willing to extend the favor to individuals.

Is it smelly sustainability? Covert cooperation? Ripe resourcefulness? I’m not sure what to think of this partnership between our city’s zoo and botanical gardens, but I could not hold the secret any longer.

And if you don’t believe me, visit Knoxville Botanical Gardens sometime this fall.

Take a whiff.

R.J. Vogt is a senior in College Scholars. He can be reached at [email protected].