All those dried up stalks, husks and cobs left in corn fields
after every fall's harvest could be a key to enhancing the
environment, say Iowa State University researchers.
They say partially burning some of the residue left in corn
fields 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.
Robert C. Brown, Iowa State's Bergles Professor in Thermal
Science, will lead a team of researchers studying the idea.
The team includes Randy Killorn, an Iowa State professor
of soil science, plus government researchers from the U.S.
Department of Agriculture, the U.S. Department of Energy
and industry researchers from Cargill Inc., Eprida and iPrismGlobal.
U.S. Agriculture Secretary Mike Johanns recently announced
the three-year project 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
of them won grants. Final details of the grants are expected
to be set by early next year.
"This cooperative conservation partnership benefits
our nation with enhanced energy security, a cleaner environment
and revitalized rural economies," Johanns said in the
statement announcing the grants. "The selected projects
support President Bush's goal to enhance renewable energy
supplies. The grants will help to develop additional renewable
energy resources and expand markets for agricultural products."
Brown's research team will focus on this process:
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.
Brown said there should be three significant results: Farmers
producing their own renewable energy to manufacture fertilizer
for their fields. Farming that improves soils because the
added charcoal supports soil organisms. And the charcoal
sequestering carbon in the soil, thus reducing the amount
of greenhouse gases in the atmosphere. 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.
Brown uses the phrase reinventing agriculture when he talks
about the process.
"The conventional goal of good land stewardship is
to minimize soil degradation and the amount of carbon released
from the soil," he said. "This new approach to
agriculture has the goal of actually improving soils."
He said the practice of improving soil by adding charcoal
has been traced back to the Amazon basin in the days before
Christopher Columbus. People there created dark and productive
soils (know as "terra preta," or "dark earth" soils)
by adding charcoal mixed with manure. Those soils are still
more productive than surrounding soils that weren't treated
with charcoal.
Killorn, who will study soil fertility as part of the research
project, said putting corn stover to work for the environment
shows a lot of potential.
"It looks pretty slick, taking these corn stalks and
turning them into bio-oil and charcoal," he said. "If
everything works the way we think it will, this looks like
a good deal."