A farmer in Osage IA, has been researching low-tech, small scale methods for recovering heat from composting corn grain and stover for space heating.
Eric Jellum and his wife moved to Osage, IA from Washington State in 1999 and began farming at that time. They grow corn and soybeans in a 2-year rotation, except where mixed grass/alfalfa hay has been included in the rotation. Before coming to Iowa to farm, Jellum worked for Washington State University for about 20 years at one of their outlying research stations. He has a Masters Degree in Soil Science and about 12 years of farming experience.
“I came to Iowa to farm not only out of interest and desire to farm but because I wanted to immerse myself in the problems and challenges that farmers deal with in order to more effectively contribute toward attaining a more sustainable agriculture,” explained Jellum.
Jellum wanted to use the energy in their corn for space heating and still have an organic residue that could be returned to the soil to maintain soil quality. In 2005 he submitted a proposal to the North Central Region Sustainable Agriculture Research and Education (NCR-SARE) Farmer Rancher Grant program, and was selected for funding.
His goal was to conduct a pilot trial with both corn grain and stover to see how feasible composting for heat recovery could be. He worked with Kapil Arora, an agricultural engineer from Iowa State University, who provided input regarding the design and implementation of the research. The motivation for the project was to use locally grown corn and return the nutrients and an organic residue back to the soil in a closed, sustainable loop to maintain or improve soil quality.
“I was a bit surprised to discover that aerating a large and static corn stover compost pile was really fairly easy,” said Jellum. “The stated purpose in composting manuals for turning a compost pile or windrow is generally for aeration. That is probably true for dense, high moisture, highly degradable compost. The biggest problem I encountered for static composting was how to recycle the water that steamed out of the compost interior and condensed on the surface back into the interior without turning the pile, which would preclude embedding a means of heat recovery in the compost pile.”
Jellum is hopeful that SARE projects like this would ideally result in turnkey ideas that could be readily employed on the farm. He hopes his project will contribute something to another concept that may ultimately be engaged on the farm.
“The bioeconomy that is developing to use crop residues and dedicated crops for energy and chemical production could have devastating effects on soil quality and the productivity of our agricultural systems if there are no residues analogous to manure that can be returned to the soil,” said Jellum. “This project was intended to see whether composting for heat recovery looked like a fruitful enough path to head down and conduct more research. It would be unrealistic to expect a single project like this to be wildly successful, but I think it answered some basic questions that suggest some logical next steps.”
Jellum shared information from his project at a presentation at the 2006 SARE National Conference at Oconomowoc, WI.
Read more about Jellum’s project online at http://www.sare.org/MySare/ProjectReport.aspx?do=viewRept&pn=FNC05-562&y=2008&t=1, or contact the NCR-SARE office for more information.