Historic Biomass Harvest Taking Place This Fall in Iowa

The first commercial harvest of corn biomass for making cellulosic ethanol is taking place this fall in Iowa. Poet LLC has 85 farmers on contract to harvest and deliver bales of cobs and light stover to its storage facility at Emmetsburg in northwest Iowa.

Published on: Sep 21, 2010
The first commercial biomass harvest will take place this fall near Emmetsburg in northwest Iowa. The corncobs and light stover harvest by 85 farmers is part of Poet LLC's cellulosic ethanol initiative called Project Liberty.

Poet, a leading ethanol manufacturer, already has a 55 million-gallon-per-year ethanol plant at Emmetsburg producing ethanol from corn grain. The company is scheduled to start construction in 2011 on a facility next door that will make cellulosic ethanol from cobs, husks and some of the leaves of corn plants.

The biomass will be collected this fall for the first time by 85 farmers in the area around Emmetsburg. It's a commercial harvest, the farmers will be paid for the bales they harvest and deliver. But this is also a test to see how the system for harvesting, handling and storing biomass will work. Poet plans to start producing ethanol from the cob-stover bales when the new plant opens, which is set for 2012 if construction stays on schedule. Poet has a 22-acre outdoor storage facility for bales at the Emmetsburg site.

Using big balers instead of collecting pure cobs

Poet's Project Liberty director Jim Sturdevant says after experimenting with several different cob collection methods last fall, Poet and the farmers have decided to use the cob-stover bales instead of harvesting pure corncobs. Why use bales rather than loose cobs as a feedstock? Mainly because the biomass can be harvested with big round balers or big square balers that many farmers in the area already own. They won't have to buy special equipment such as cob collecting cars to pull behind combines.

"The combine just dumps a windrow out behind it as it harvests grain," explains Sturdevant. "The straw chopper and spreader is shut off. Later a tractor pulling a big round baler or a big square baler will come along and collect that windrow. That's the approach that the majority of the farmers who have signed the contracts have chosen to use for this fall."

Poet has been working with Iowa State University agronomy and ag engineering researchers to determine if there are any nutrient or soil erosion control issues when harvesting biomass. Sturdevant says the research data indicates that collecting biomass in bales of just cobs and light stover in this system will not negative impact the land.

Farmers will harvest about one ton of residue per acre

Some people have voiced concern that harvesting stover may remove too much crop residue, thus aggravating soil erosion problems. And some are also concerned about removing too much soil fertility, which would have to be replaced by applying higher rates of fertilizer, which increases costs to grow the crop. "We believe farmers can be very comfortable with this system we are trying out on a commercial basis this fall, because they will be removing only 25% of the aboveground stover from their fields," says Sturdevant. "So they won't harm or impact the soil."

The ISU studies show on average a little over 4 tons of total corn crop residue per acre is produced in the typical fields in the Emmetsburg area. Harvesting only 25% of that with the baler would remove only about 1 ton per acre.

The 85 farmers with contracts will get from $45 to $60 a ton for the biomass bales. They will deliver the bales to Poet at Emmetsburg and most of the farmers are within a 45 mile radius of Emmetsburg. The biomass material has to be fairly dry for it to store well in the bales. So everyone involved in Project Liberty is hoping for a dry fall.

They're hoping to get a dry fall to bale the biomass

To help ensure quality material, Poet wants the farmers to bale the cobs and stover fairly soon after a field of corn is harvested for grain. The baler has to be set to run 8 inches or so above the ground to avoid getting dirt into the bale. Mold and dirt in the stover material would harm the fermentation process for making cellulosic ethanol. Bales have to be triple wrapped with plastic bale mesh.

Farmers around Emmetsburg who've contracted with Poet view this fall's activity as a learning experience to work out the wrinkles and develop a system. Sturdevant says after some farmers worked with Poet and experimented with several different cob collection methods last year, Poet and the farmers have settled on using balers in 2010. The decision to harvest cobs and light stover instead of collecting pure cobs as a primary feedstock has appeal for farmers because collecting only the cobs would require pulling a cart behind the combine and that slows down corn harvesting.

How much P & K fertility will farmers have to replace?

Dick Nelson and Ed Noonan are farmers involved in Project Liberty who think using a big round baler or big square baler will work. Nelson already owns a baler. Noonan will hire a custom operator to bale and haul his harvest of cob-stover material.

"The combine just dumps a windrow behind it as it moves through the field as it harvests the grain," says Nelson, show farms near Emmetsburg. "A tractor pulling a big round or big square baler comes along and picks up the windrow. That's the approach most farmers who signed contracts want to take. That's what we want to try out this fall."

Nelson believes collecting the biomass will not harm his land. "I think we can be very comfortable and confident in removing only 25% of the aboveground stover from fields and not harm or impact the soil," says Nelson. "That's only about one ton of cobs and stover removed per acre. We grow a lot of corn on corn and with today's bigger yields that produces a lot of crop residue which tends to build up."

He adds, "We've baled some cornstalks for use as cattle bedding each year for many years without creating erosion and without removing too much phosphorus or potassium from the soil. If you're just harvesting mainly cobs and light stover and not the stalks, you aren't removing that much fertility from the field."