A "Soil Lorax" perspective on corn stover for advanced biofuels

Authors: Johnson, Jane

Submitted to: Agronomy Journal
Publication Type: Literature Review
Publication Acceptance Date: 4/26/2018
Publication Date: 7/5/2018
Publication URL: https://handle.nal.usda.gov/10113/6471067
Citation: Johnson, J.M. 2018. A "Soil Lorax" perspective on corn stover for advanced biofuels. Agronomy Journal. 110:59-62. https://doi.org/10.2134/agronj2018.02.0093.
DOI: https://doi.org/10.2134/agronj2018.02.0093

Interpretive Summary: The crop residues are the plant materials remaining in the field after a producer has harvested the grain. It includes leaves, stems or stalks. In the case of corn, it also includes the corn husk and cobs. In corn, these residues are also referred to as stover. Corn stover contains a compound called cellulose, which can be used to generate ethanol. Ethanol is often blended into gasoline. Currently, most of the ethanol produced to add into gasoline is made from the starch found in corn grain. Ethanol made from cellulose is considered an advanced biofuel. Advanced biofuels are made from non-food sources like crop residues. Using nonfood materials offers economic benefits to the producer by providing two cash products from the same acre of land in the same growing season. The ethanol made from plant material provides a source of fuel for vehicles that does not release carbon dioxide from fossil fuel. The release of carbon dioxide into the atmosphere that had been captured in the fossil fuels is contributing to the dramatic rise in greenhouse gases in the atmosphere. It is important to note that while there are benefits from using residues like corn stover for energy, there are also risks. Crop residues when left in the field keep the soil covered so it is less likely to wash or blow away with water or wind erosion. If too little residue is left on the soil, erosion can occur damaging the soil. Residues also feed many soil organisms like worms, fungi and other soil microbes, which are needed to make soil organic matter. Soil organic matter is important for many of a soil’s characteristics that make it productive for growing crops. The review discusses balancing using residues or some of the residues while still making sure the soil is protected so it can be used to feed us.

Technical Abstract: Crop residues like corn (Zea Mays L) stover are potential feedstock for production of advanced biofuels (e.g., cellulosic ethanol). Utilization of residue like stover for biofuel feedstock may provide economic and greenhouse gas mitigation benefits; however, harvesting these materials must be done in a manner that protects the soil. This paper summarizes an introductory overview presented at the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and Soil Science Society of America (SSSA) workshop in Sacramento, California, on crop residue removal for advanced biofuel production. Strategies to protect the soil resource to balance current and future societal needs will be discussed. The overview briefly acknowledges benefits of utilizing stover as feedstock. Associated risks of harvesting crop residues in regard to soil properties is discussed as well as strategies to minimize or mitigate risk. It is paramount to safeguard the soil so this indispensable resource continues a wide range of services including feeding and clothing a growing population.