Biochar Manure Lagoon Cover
When you burn wood in a campfire, the black chunks left behind once the fire is out are a carbon-rich substance called biochar. Biochar is like a sponge. Its chemical charge attracts and holds on to nitrogen, phosphorous, potassium ions, heavy metals, and other compounds. It can also trap gasses at the water’s surface.
Brian Dougherty is a graduate research assistant at Iowa State University. As an undergrad at Oregon State University, he researched the possibilities of using biochar as a cover for manure lagoons because of its unique physical and chemical properties.
"The main one is they have an extremely high porous internal structure. A few ounces of biochar can have an internal surface are the size of a football field, it’s hard to get your head around, but that’s the case. So, that porous structure makes it very lightweight and buoyant so it would float on the surface of the manure, that’s the idea," says Dougherty. "And then it also has the potential to capture nutrients from the manure because of the properties I mentioned previously."
When the lagoon is emptied, the biochar could be blended in with the rest of the manure and spread on the field.
"It would hopefully take up some of the nutrients and hold them, and then serve as sort of a slow-release fertilizer source when they’re applied to the soil," he says. "A lot of livestock operations have more nutrients than they need for the land base that they have. There’s also a problem with leaching from farm fields so the biochar could potentially be a mechanism for capturing some of those nutrients."
Learn more about biochar and its benefits