Judiciously decomposing organic matter from 700 degrees Fahrenheit to 1,200 degrees F, without oxygen – a process known as pyrolysis, very different from incineration – and retaining nutrients from dairy lagoons can transform manure into a manageable, ecologically friendly biochar fertilizer, according to new research published July 22 in Nature Scientific Reports.
That would allow dairy producers to stop storing excreta in on-farm lagoons or spreading it only in nearby fields.
“Manure is usually a liquid problem and it has increasingly been an issue of disposal,” said Johannes Lehmann, the Liberty Hyde Bailey Professor in the School of Integrative Plant Science Soil and Crop Sciences Section, in the College of Agriculture and Life Sciences. “Using pyrolysis of solid manure and retention of nutrients from the liquid onto the biochar, we can create a fertilizer from waste. That’s a marketable commodity.
“Farmers can spread this fertilizer when the field crops need it, instead of when the farmers need to get rid of manure,” he said.
Commercial fertilizer made of nitrogen, phosphorus and potassium is created using carbon inputs like natural gas, sulfur, coal and rock deposits. If agriculture can recycle nitrogen, Lehmann said, farming can reduce the carbon input that comes from fossil fuel.
