Steve McKinley
Abengoa Bioenergy

 As more and more farmers are either contracting their biomass for use in the Hugoton, KS, ethanol biorefinery to open in late 2013, or harvesting for sale to feedlots, etc., the main concern (and debate) seems to be on exactly how much is too much when it comes to removing biomass?

            Agronomist, soil researchers and the NRCS agree, the amount taken depends on what type of soil you are growing a crop on as well as the environmental conditions of the region you farm in.

As new cellulosic technology emerges, crop residues have been identified as a replacement for grain in ethanol production. The collection of crop residues as a feedstock for biomass ethanol is a huge step to help solve the United States overreliance on imported fuels. However, residue harvest from agricultural lands can – if done improperly or with no regard to the land – induce soil and environmental degradation with detrimental effects on soil quality.

When the new Abengoa Bioenergy Biomass of Kansas (ABBK) biomass-to-ethanol biorefinery opens in late 2013 it will require upwards of 350,000 to 400,000 tons of biomass to fuel its 25 million gallons of ethanol production a year. Making sure that ABBK’s contract farmers can provide the 1,100 tons/day of biomass to the plant in a sustainable, environmentally sound manner rests in the hands of Dr. Tom Robb, Abengoa Bioenergy’s manager of institutional relations and Brad Niehues, biomass field manager, both located in Hugoton, KS.

“One of the major reasons southwest Kansas was selected for the site of our biomass-to-ethanol biorefinery was because of the cultural practices and the climate,” notes Dr. Robb. “Traditionally southwest Kansas is continuous corn. Most farmers don’t burn their fields off any more to remove excess crop residues. Many don’t have the manpower to do the tillage they used to do or have chosen to reduce trips across the fields to reduce diesel fuel costs and soil compaction. Combine those factors with the fact that the climate is conducive to minimizing residue breakdown and suddenly you have an overabundance of crop residue for us to buy and harvest. It’s a win/win for us and the farmer who knows he needs to manage his crop residues to assure proper seed germination and a strong crop stand.”

“Residue management is nothing new in this part of the country,” adds Niehues. “Strip tillage (tilling a small section of the row and planting right into the tilled area) has been adopted by a lot of farmers as a way to plant thru the residue. They started having good results, but consequently, after several years of continuous corn-on-corn, the residue has become an issue that’s affecting crop stands, fertility costs and tillage practices. Another factor that has allowed soil residue to become more prevalent in fields is the fact that many farmers no longer have cattle to graze those fields. And in recent years, feedlots have been buying corn stover to feed their cattle. Farmers are looking at ways to help manage their residue.”

“We see residue management as a two-step issue,” adds Dr. Robb. “First you need to remove the proper amount of soil residue to assure proper seed germination and a good stand. Secondly, you need to remove the proper amount to assure that if you do get a 50 mph wind, you don’t threaten valuable topsoil. Proper biomass management allows the farmer to be more productive in his grain production system and secondly it protects the value of his asset – his land. Residue management is not a one-stop process but rather a program that each individual producer needs to understand and implement. We’re working with the NRCS to help educate farmers on the proper amount of field residue to leave on their fields to avoid problems.”

According to Andy Heggenstaller, Pioneer Seed Agronomy Research Manager in Iowa, growers who achieve high yields per acre typically find that residue becomes difficult to manage. “If the residue buildup can be reduced then stand establishment concerns when the next crop is grown can be avoided,” the agronomist notes. A second benefit is that nitrogen tie-up caused by residues can be reduced. At the moment, some farmers growing corn increase their use of nitrogen fertilizer to allow for the nitrogen that is mixed up with microbes. It can be a time-consuming and costly process. Excessive tillage can also harm the crop’s soil and organic matter is lost when oxygen is put into the soil through tillage. However, if better residue management practices are introduced, challenges relating to reduced-tillage systems can be overcome.

Residue removal decisions will need to be made by the individual producer (and their agronomist) based on profitability and sustainability of their farming operation. There is ample research that shows that an abundance of residue limits the corn yield potential. Throughout various studies conducted in Stevens County (southwest Kansas), controlled residue removal did not have any significant affect on grain yield or corn emergence. Residue removal may be accomplished sustainably depending on inherent soil characteristics and will need to be considered at each potential removal site.

“We are working closely with the NRCS to determine the effects on soil quality and productivity from long-term removal, different residue removal rates, irrigated vs. dryland, contrasting topography and combine cutting heights,” Dr. Robb notes. “It is our highest priority to make sure we provide a sustainable program to our contract biomass farmers. We have to make sure they are comfortable with how we are harvesting their fields and that it does not impede or impact how they plant those fields for future crops. Our mission is long-term sustainability and that all starts and ends with the contract farmer feeling good about how we are impacting his land.”

KSU Agronomists have conducted numerous studies on residue removal, and specifically in southwest Kansas, on the finer textured silty clay loam soil, and found minimal effects of residue removal on soil physical properties. Additionally, soil aggregates in Hugoton (Stevens County) were able to resist breakdown due to increased clay content as well as increased organic matter levels, even when residue was continuously removed.

Custom Harvesting Helps Maintain Quality and Sustainability

And in order to help maintain the integrity of the soil and preserve a constant flow of biomass, ABBK has contracted two professional firms to do all the biomass harvesting. “We knew many farmers were not set up to give us the large bales necessary for our production flow, so rather than lay the burden on them to purchase machinery, we hired two professional harvesting firms to schedule and handle all the harvesting,” says Dr. Robb. “We also knew as this harvesting process grew, we would need to have professional engineers and agronomic professionals help us adjust our harvesting techniques and biomass bale transportation needs. This allows us the opportunity to develop new machinery, hone our harvesting techniques and maintain a schedule that requires we harvest 1,100 tons of biomass a day.

“ABBK will assume the cost and management of harvesting the contracted acres,” adds Dr. Robb. “All the contract farmer needs to do is give us permission to go on the field after he has harvested his crop. We will remove the biomass according to NRCS and Abengoa standards, however, we will do what the farmer wants us to do regarding the amount of biomass that is removed. If he plans to plant wheat behind the biomass harvest and doesn’t want a lot of crop residue to plant into, he may request we remove more. The final call on this belongs solely to the contract farmer. He knows best what he wants to do with his fields.

ABBK contract harvesters will cut, rake, bale and transport the material off the fields. The contract farmer has no expense associated with the removal of the biomass. Alternatively, if the farmer has the manpower, equipment and time to harvest and store the contracted fields, ABBK will pay him for his efforts and expenses based upon the contract terms. “We want the farmer to make the most money he can from contracting his biomass acres with us,” states Dr. Robb. “That’s how this stays a win/win sustainable program for us both.”

“The impact of residue removal is dependent on characteristics of the soil present,” concludes Niehues. “That is why each farmer needs to understand his farm’s soil profiles, chemical properties and erosion issues. We will work with each contract farmer to meet his biomass removal needs based on his cropping plans, nutritional needs and tillage practices. Sustainability starts with good communication between us and the contract farmer.”

Any producer interested in learning more about the contracting opportunities in association to the new biomass facility needs to contact Brad Niehues directly at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

For more information on the processes and uses of biomass and ethanol, please log on to www.abengoabioenergy.com.