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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #300579
Title: Development of sustainable corn stover harvest strategies for cellulosic ethanol

Author
item BIRRELL, STUART - Iowa State University
item Karlen, Douglas
item WIRT, ADAM - Poet

Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2014
Publication Date: 2/7/2014
Citation: Birrell, S.J., Karlen, D.L., Wirt, A. 2014. Development of sustainable corn stover harvest strategies for cellulosic ethanol. BioEnergy Research. 7:509-516.

Interpretive Summary: POET-DSM (this is the true name of the company, it's not an acronym) and two other commercial entities are preparing to launch three cellulosic ethanol conversion facilities in 2014. This study showed that neither grain yield nor soil nutrient levels were significantly affected by any of the stover harvest treatments evaluated at this research site. Spatial and seasonal variability were by far the most influential factors affecting both parameters. This emphasizes the importance of developing and maintaining a routine soil fertility testing and nutrient management program, before harvesting crop residues for any purpose. Failing to do so could serve as a tipping point that could ultimately reduce crop yields and degrade soil resources. The four-year results of this project have shown that with good soil and crop management practices, corn yields should be sufficient to support a sustainable corn stover harvest of 1 metric ton per hectar (1 ton per acre) from this and similar fields. This information is important for those striving to develop the lignocellulosic bioenergy industry, crop consultants, research scientists and engineers, conservationists and farmers.

Technical Abstract: The U.S. EPA identified corn (Zea mays L.) stover as “the most economical agricultural feedstock…to meet the 16 billion gallon cellulosic biofuel requirement.” They estimated that 7.8 billion gallons of ethanol would come from 82 million tons of corn stover by 2022. POET-DSM Advanced Biofuels is constructing a commercial scale plant near Emmetsburg, IA, and expects to begin producing cellulosic ethanol from corn stover in 2014. To prepare for the launch of this new enterprise, POET-DSM has been working through ‘Project Liberty’ with farmers, researchers, and equipment dealers on harvest, transportation, and storage logistics of corn stover for the past several years. To quantify the potential impact of stover harvest on soil productivity, a multi-year cooperative research project was developed with ISU engineers and USDA-ARS soil scientists. A field study was conducted on a 50 ha (125 acre) Clarion-Nicollet-Webster site using seven stover management treatments including no removal, cobs only, and harvest of approximately 50 or 90% of the above-ground biomass. The quantity of stover harvested, subsequent grain yields, and soil-test results for the first four years are presented. Although there were no statistically significant differences among the seven stover harvest treatments, our initial conclusions are that spatial variability is a major factor and should be addressed through site-specific management and that either tillage intensity should be reduced or grain yields increased to ensure long-term sustainability of the various harvest strategies. This study also shows how plot-scale and on-farm research information from the Sun Grant Regional Partnership’s Corn Stover Team studies can be scaled up to help guide viable, commercial cellulosic bioenergy investments.