|GRESHAM, GAROLD - Idaho National Laboratory|
|LAIRD, DAVID - Iowa State University|
|OCHSNER, TYSON - Oklahoma State University|
|Novak, Jeffrey - Jeff|
|Halvorson, Ardell - Collaborator|
|ARRIAGA, FRANCISCO - University Of Wisconsin|
|LIGHTLE, DAVID - Retired Non ARS Employee|
|HOOVER, AMBER - Idaho National Laboratory|
|EMERSON, RACHEL - Idaho National Laboratory|
Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2014
Publication Date: 11/17/2014
Publication URL: http://handle.nal.usda.gov/10113/59995
Citation: Johnson, J.M., Karlen, D.L., Gresham, G.L., Cantrell, K.B., Archer, D.W., Wienhold, B.J., Varvel, G.E., Laird, D.A., Baker, J.M., Ochsner, T.E., Novak, J.M., Halvorson, A.D., Arriaga, F., Lightle, D.T., Hoover, A., Emerson, R., Barbour, N.W. 2014. Vertical distribution of structural components in corn stover. Agriculture. 4:274-287. doi: 10.3390/agriculture4040274.
Interpretive Summary: Corn stover, the portion of the plant that generally remains in the field after grain is harvested, could also be collected and used to produce bioenergy, animal feed, or other products. This study quantified the chemical composition of the plant material collected from eight locations around the U.S. The unique contribution of this work is that the analyses were conducted for plant fractions collected in four-inch segments starting at the bottom of the plant. The information will help those striving to balance new energy and bio-product uses for corn stover with the more traditional uses for stover -- namely soil erosion control and nutrient cycling.
Technical Abstract: In much of the United States, corn (Zea mays L.) stover is the most abundant and widespread agricultural residue. Because of this abundance, stover has been targeted as feedstock for second generation fuel production and other bio-products. Ethanol yield is linked to sugars, while structural components like lignin are desired for thermochemical conversion or building soil organic matter. Our objective is to report Fourier transform near-infrared (FT-NIR) spectroscopy characterization of stover as a function of vertical distribution on incremental samples collected at multiple U.S. locations. Each sample, representing a 10-cm increment from the soil surface to the primary ear at physiologic maturity or about 3-weeks later (grain harvest), was characterized by FT-NIR, and a small subset of samples assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were greater at grain harvest than physiological maturity, but harvestable biomass was less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg-1, but with an alkalinity measure of 0.83 g MJ-1, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha-1, but it would be only 1000 L ha-1 if stover harvest was restricted to the material from above the primary ear. Furthermore, based crop yields at these sites, even restricting harvest to material from above the ear may not provide sufficient biomass to maintain soil organic carbon and provide surface protection against the erosive forces of wind and water.