Straw Residue Too Valuable to Harvest
for Biofuels Production

PULLMAN, WA –– Palouse wheat growers should think twice before harvesting crop residue for cellulosic ethanol production, says Ann Kennedy, a USDA-Agricultural Research Service soil scientist.

Photo: ARS
Ann Kennedy, USDA Agricultural Research Service soil scientist.

“In the more than 100 years that we have been cultivating soils in the Palouse, we have lost about half of the original organic matter,” she said. “Organic matter provides nutrients crops need; it holds water and contributes to aggregation.”

Large aggregates, or soil clods, help prevent wind erosion.

Soil is made up principally of mineral particles, organic matter and microorganisms that break down residue into organic matter. The percentage of organic matter in a given soil varies naturally from region to region, depending on climate, soil disturbance, moisture and vegetation.

Ideally, according to Kennedy, the soils in this part of the Palouse should have about 3.5 percent organic content. In most fields, she said, it is closer to 2 percent.

Organic matter may not be what you think.

“A lot of people think residue is part of organic matter,” she said, “but that is not correct. Organic matter is well-decomposed plant material and microbes. It is black and rich and gives soil its dark color.”

Kennedy, whose current research is examining the composition of cereal crop residues and the amount of residue needed to maintain soil quality, said that in direct-seed or one- pass tillage systems at least a ton of residue per acre per year is needed to build soil organic matter over time.

In these minimum tillage systems, the intact and slowly decomposing roots also add to organic matter. In fields with multiple tillage passes, every bit of residue is needed and even then, organic matter may not increase.

She increased the percentage of organic matter in no-till research plots at the Palouse Conservation Field Station from 1.9 percent to 3.6 percent over the course of 20 years.

Tillage may mix the soil and residue too well, in essence over-feeding the microbes. The microbes will consume the incorporated residue too quickly and release most of it into the air as carbon dioxide.

“It is like going to an all-you-can-eat restaurant every day and eating too much,” she said “You cannot adequately metabolize all the food you ate. Cultivated soil is like a ‘pig out’ for microbes.”

In her trials, she was able to increase organic matter up to about 3.2 percent when the soil was tilled with a one pass-chisel.

Leaving residue on the soil surface works best. “It will tend to stay around longer, and the microbes will slowly invade it and convert it into organic matter,” she said.

Could excess crop residue be baled off for biofuels?

“You could remove the extra residue,” she said, “but it still provides surface cover and will eventually become organic matter; this residue layer is especially important if you rotate with low-residue crops. We need to constantly replenish organic matter.”

Beyond Biofuels: Renewable Energy Opportunities for US Farmers: German study


In the United States, the agriculture sector has traditionally lagged Germany in its ability to capitalize on the benefits of renewables. While farmers in the US are earning revenue from wind and biomass systems, it is at a far lesser degree than German farmers.

However, the American
agricultural community is increasingly interested in the economic opportunity of renewable energy as well as in the additional benefits to water and soil quality. For example, Germany has approximately 30 times more biogas digesters than the United States.

Dowload the report

Co-Burning Biomass Opportunities in
A Strategic Assessment

Published in June 2001, this 52-page report still offers some detailed background and references about co-burning biomass in Wisconsin.

Photo: Karl Ohm

The report was prepared by Andy Olsen, under a U.S. Dept. of Energy contract, for the Division of Energy Wisconsin Dept. of Administration.

Read the report

Submission Guidelines
for Farm Energy

To have news and other pertinent information considered for publication on FARM ENERGY NEWS.COM, please follow the basic and detailed guidelines found at: Submit Your News











Initiative will put Illinois
at forefront of farm bioenergy production

CHAMPAIGN, Ill. — A $500 million research program announced last year by the energy company BP will bring farm bioenergy production to Illinois on a grand scale, say researchers at the University of Illinois at Urbana-Champaign.

Illinois will join the University of California at Berkeley and the Lawrence Berkeley National Laboratory in forming the new Energy Biosciences Institute, with UC Berkeley taking the lead.

As part of the EBI, some 340 acres of farmland at the Urbana campus will be devoted to the study and production of feedstock for biofuel production.

Researchers will explore the potential benefits of using corn crop residues, switchgrass, Miscanthus (Miscanthus x giganticus: a hybrid grass that can grow 13 feet tall), and other herbaceous perennials as fuel sources.

The initiative will explore how adequate supplies of high quality plant biomass can be sustainably produced and utilized in facilities that convert the biomass to fuels.

“The proposal from UC Berkeley and its partners was selected in large part because these institutions have excellent track records of delivering ‘Big Science’ – large and complex developments predicated on both scientific breakthroughs and engineering applications that can be deployed in the real world,” said BP Group Chief Executive John Browne.

Stephen P. Long, the Robert Emerson Professor of crop sciences, will lead the Energy Biosciences Institute initiative for Illinois.
Photo: Univ. of Illinois

“This program will further both basic and applied biological research relevant to energy. In short, it will create the discipline of Energy Biosciences. The Institute will be unique in both its scale and its partnership between BP, academia and others in the private sector.”

Previous support, from the Illinois Council for Food and Agricultural Research, enabled U. of I. scientists to pioneer research in the use of Miscanthus as a bioenergy crop.

The researchers have found that this hardy perennial grass is more than twice as productive as switchgrass, another biofuel source. This makes Miscanthus a front-runner in the effort to find an economical and environmentally friendly fuel source.

Illinois will also work with its partners in the EBI to explore the economic and environmental impact of the process – from farmland to fuel consumption. Understanding and reducing the environmental impacts of biofuel production will be a key focus.

“This will place us at the forefront of farm bioenergy production,” said Stephen P. Long, the Robert Emerson Professor of crop sciences in the College of Agricultural, Consumer and Environmental Sciences and a professor of plant biology in the College of Liberal Arts and Sciences.

Long, who also has appointments at the National Center for Supercomputing Applications and the Institute for Genomic Biology, will lead the EBI initiative for Illinois. Laboratories and offices for the Illinois operation will be in the new IGB facility on Gregory Drive in Urbana.

Feedstock development is one of five research areas at the EBI. The others are biomass depolymerization (breaking down plant material for use in biofuels), fossil fuel bioprocessing (converting heavy hydrocarbons to cleaner fuels) and carbon sequestration (removing or preventing increases in atmospheric carbon), socio-economic systems (social and economic issues related to these new technologies) and biofuels production.

U. of I. scientists have pioneered research in the use of Miscanthus – which can grow 13 feet tall – as a bioenergy crop.

miscanthus plant
Photo: Univ. of Illinois / David Reicks

Discovery and development research centers at each site will support the scientific divisions.

In addition to feedstock development and socio-economic research, Illinois will work with the other research institutions on biofuels production.

UC Berkeley will lead this part of the project, with Illinois joining the search for the most efficient use of microbes to harvest the energy in plants for biofuels.

“This exciting venture allows two of the country’s greatest public universities to work together to develop renewable energy – an initiative that will play a critical role in the success and security of our nation,” Herman said.

“Addressing the problems facing society is the business of our institution. The scientists leading this important work are continuing Illinois’ rich heritage of paradigm-changing discovery and innovation.”

U. of I. Chancellor Richard Herman thanked BP for engaging the two universities in what he called a noble enterprise.

Submission Guidelines for Farm Energy

To have your company's news releases, research and other pertinent information considered for publication on FARM ENERGY NEWS.COM, please follow these basic guidelines found at: Submit Your News