AMES, Iowa —

Farming in Iowa comes down to dirt.

And how healthy it is.

A new study with Iowa State University College of Agriculture's agronomy department researchers shows how farmer Bryan Sievers of Stockton, Iowa, is improving his soil.

This project started 12 years ago.

Sievers put in something called an anaerobic digester. It's basically a giant composter that uses microorganisms to break down organic waste.

"I just knew that it was a way to take your manure, process the manure, and maximize the value of that resource," Sievers says. "The material that comes out is, is really nature's best fertilizer."

The result is biogas, a slurry, and a solid, called digestate.

Sievers uses the digestate, and he has to apply little manmade fertilizer.

Sebastian Villarino, Fernando Miguez,

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