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Reducing Phosphorus Concentration of Ethanol Distiller Byproducts by Using Low Grain Phosphorus Corn
Ethanol production plants are using about 800 million bu of corn each year to produce ethanol. In the ethanol production system, the starch is converted to ethanol and CO2 and the remaining grain material is called distiller byproduct (wet distiller grain plus soluble or dry distiller grain plus soluble). This byproduct is high in energy, protein, and P contents and is usually fed to feedlot cattle and other livestock. Removal of starch from grain concentrates P in the byproduct and when this high P material is added to ration, it increases P concentration of the ration and subsequently increases manure P concentration.
Corn hybrids have different concentrations of P in grain. Results of a two-year field study conducted by the author in 1999 to 2000 indicated grain P concentration range of 0.21% to 0.33% among 12 commercial corn hybrids. Analysis of some other commercial hybrids in 2003 indicated that high P hybrids have P concentrations that can be more than double of those for low P hybrids. These low grain P hybrids can be used in rations to reduce its P content or can be used in ethanol production to reduce P content of the byproduct and hence make it a more environmentally friendly feedstuff. By reducing P concentration of the byproduct, the P concentration of manure will also reduce and that lessen the concern about soil P accumulation in the soil.