Bioenergy

Partially Burning Biomass May Reinvent Agriculture

Researchers say partially burning some of the residue left in corn fields (stalks, husks and cobs) after every fall’s harvest produces products that can be used to improve soil fertility, boost in-soil storage of greenhouse gases and reduce the amount of natural gas used to produce anhydrous ammonia fertilizer.

U.S. Agriculture Secretary Mike Johanns recently announced a three-year study that will be supported by $1.85 million from the Biomass Research and Development Initiative, a joint project of the U.S. agriculture and energy departments. More than 670 research teams applied for initiative funding. Eleven won grants. The leader of the Iowa State University researchers to study the process is Robert C. Brown, Iowa State’s Bergles Professor in Thermal Science, who is said to describe the research as reinventing agriculture: Corn stover will be harvested from fields and partially burned to create charcoal and a bio-oil about as thick as motor oil. The bio-oil will be reacted with steam to produce hydrogen. That hydrogen will replace the natural gas typically burned to make anhydrous ammonia fertilizer. The fertilizer and charcoal will be incorporated into the soil. “The conventional goal of good land stewardship is to minimize soil degradation and the amount of carbon released from the soil,” said Brown. “This new approach to agriculture has the goal of actually improving soils.” Brown estimates a 640-acre farm could sequester the equivalent of 1,800 tons of carbon dioxide in the soil. That’s the annual emissions created by about 340 cars.