by Dan Voigt
The technology of cellulosic ethanol production is based in great part on the quantity of cellulosic material available for plants that utilize the technology, such as POET/DSM's Project Liberty plant in Emmetsburg. Since the inception of Project Liberty, area producers who have been harvesting their corn residue each Fall have worked on the basis of taking just 25 percent of the corn stover, ie: stalks, husks and cobs, from the field after the harvest, usually in one-pass baling.
But ongoing research by POET/DSM as well as Iowa State University and the United States Department of Agriculture may soon lead producers to the ability to harvest more stover from their fields, without hurting the growing potential of the soil. Through the use of cover crops after harvest, a cornfield could "re-charge" its growing capacity even with additional stover being removed.
COVER?CROP?SEEDING - A Hagie Interseeder unit seeds cereal rye between cornrows on Dan Chism’s farm near Emmetsburg last Tuesday afternoon. The seeding is part of ongoing research on cover crops for biomass research for POET/DSM’s Project Liberty. The research is part of an ongoing cooperative effort between POET/DSM, Iowa State University and the United States Department of Agriculture on biomass production and soil sustainability. -- Dan Voigt photo
"Agriculture is the solution to so many of the world's challenges, and there's an enormous opportunity in cellulosic ethanol," POET CEO Jeff Broin said. "As this industry starts to grow, we're working to make sure that it's done in a way that is as sustainable as possible."
The idea of sustainability of the land, or the ability of the land to continue to grow crops requires many factors sunlight, moisture, nutrients in the soil and proper land management. To ensure proper land management, Iowa State University and the USDA have worked with POET/DSM's biomass team for eight years now, monitoring the soil under different residue removal practices. Charting production on fields where varying levels of stover were removed has provided useful data, but in addition to that research, in 2015, POET Biomass tried an experiment were two fields were seeded with a cover crop - a mix of tillage radish and oats, after the corn was harvested, to see what impact field cover has when paired with a variety of tillage practices and residue removal rates.
"This research is really about two things, soil sustainability and soil health, noted Alex Johnson, Regional Biomass Coordinator for POET. "The idea is that incorporating a cover crop over the winter months might help the soil health and sustainability.'
The research aims to determine how cover crops affect soil health, biomass harvesting and feedstock quality as well as the quantity of biomass that can be sustainably removed.
"One year of data is too soon to make any bold statements, but we're certainly optimistic about pairing cover crops with biomass harvesting for cellulosic ethanol in the future," said Associate Biomass Research Scientist Alicia ElMamouni.
"The first year's seeding of the radishes and oats grew well enough through the Fall, but we didn't get much biomass from them," Johnson noted. "But they did establish well."
In looking at other ideas for cover crops, the POET Biomass team completed a seeding of cereal rye as a cover crop near Emmetsburg with the cooperation of area producers. The seedings were done this past Tuesday, Aug. 23.
Utilizing the services of Iowa Cover Crops of Jefferson and their Cover Crop Interseeder, a high-clearance air seeder built by the Hagie Corporation, three local cornfields were seeded with the cereal rye seed. The Interseeder uses a 90-foot wide boom with drop tubes to spread the rye seed between the cornrows. Once seeded, the rye will take root before the snow flies and will lie dormant until next spring, when it will continue to grow into a grassy cover crop that can quickly be killed off prior to planting. But as the plants die off, the root systems they established will decay to provide additional nutrients for the soil.
"We get the benefit of obtaining the nutrient value of the rye back into the soil, which is nutrient cycling," Johnson explained, "But an added benefit of having that cover crop on the soil is that as the Spring rains fall and the snow melts, that cover crop will help act as a filter of sorts, cutting down on surface nitrate runoff which could in turn reduce nitrate levels running into rivers and streams."
The biomass team will continue to share results of its soil sustainability work with farmers and other similarly focused organizations to help make sound farm management decisions.
"We're not looking at cover crops as a way to be able to take 50 percent of stover off the fields," Johnson pointed out. "We need to look at what the cover crops can do with the different tillage practices, like strip tillage, ridge till and no-till farming, and see was works best using good management practices."