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Carbohydrate and nutrient composition of corn stover from three southeastern USA locations

Mourtzinis, Spyridon, Cantrell, Keri B., Arriaga, Francisco J., Balkcom, Kipling S., Novak, Jeff M., Frederick, James R., Karlen, Douglas L.
Biomass and bioenergy 2016 v.85 pp. 153-158
Zea mays, bioethanol, biomass, carbohydrate composition, carbohydrates, corn, corn ears, corn stover, ears, energy crops, ethanol, ethanol production, feedstocks, field experimentation, harvesting, leaves, near-infrared spectroscopy, nutrient content, nutrients, sampling, soil, Alabama, South Carolina
Corn (Zea mays L.) stover has been identified as an important feedstock for bioenergy and bio-product production. Our objective was to quantify nutrient removal, carbohydrate composition, theoretical ethanol yield (TEY) for various stover fractions. In 2009, 2010, and 2011, whole-plant samples were collected from one field study in South Carolina (SC) and two in Alabama (AL). Soils at the SC site were classified as a Coxville/Rains-Goldboro-Lynchburg association, while those in AL were either Compass or Decatur. Plants were collected from two 1-m row segments, ears were removed and shelled. A portion of the remaining stalks were dried and ground to represent whole-plant stover. The remaining stalks were fractionated into stalk and leaf biomass from below the ear (bottom), stalk and leaf biomass from above the ear (top), cobs, and grain. A fifth sample representing “above-ear” biomass that might be collected mechanically was calculated using the weight ratios of the top and cob fractions. Carbohydrate and nutrient concentrations were estimated using near-infrared spectroscopy (NIRS) and TEY was calculated. The distribution of carbohydrates, nutrients, and TEY varied significantly among the corn stover fraction and research locations. This indicates that site-specific sampling and analysis should be used to optimize bioenergy and bio-product utilization of corn stover. However, at every location, the above-ear stover fractions were most desirable for cellulosic ethanol production. Furthermore, harvesting only above-ear stover fractions would reduce nutrient removal by 24–61% when compared to harvesting all stover biomass.