Nitrogen Fertilization for Ethanol Production with Sweet Sorghum and Corn G. Stevens, R. Holou, M. Rhine and D. Dunn University of Missouri-Delta Center Portageville, Missouri

60% of U.S. fuel from foreign countries

Fuel versus feed debate

Switchgrass >10 year old stands Missouri Bootheel

Nutrient Partitioning Roland Holou, PhD student November 2007 Fresh wt 4.8 tons/acre Dry wt 3.4 tons/acre

Sweet Sorghum University of Missouri-Delta Center 2007

Subfamily Panicoideae C4 photosynthesis Sugar cane (Saccharine hybrids) Sugar cane (Saccharine hybrids) Sweet sorghum (Sorghum bicolor) Sweet sorghum (Sorghum bicolor) Maize (Zea mays) Maize (Zea mays)

WWII Sugar Rationing First & Last , two years after war ended

Moonshine- sugar from sweet sorghum Cheaper sugar for making ethanol.

Sweet sorghum Positive Reports that it requires less water and nitrogen than corn. Reports that it requires less water and nitrogen than corn.Negative Infrastructure not developed to handle large quantities of juice. Infrastructure not developed to handle large quantities of juice.

Objective Sweet sorghum- Determine optimum N rates for producing ethanol Sweet sorghum- Determine optimum N rates for producing ethanol Irrigated Tiptonville silt loam soil Sweet sorghum– 0, 20, 40, 60, 80, 100, 120 lb N/acre Corn- 0, 40, 80, 120, 160, 200, 240 lb N/acre Sorghum variety: M81E, 4 replications

Corn, bushels per acre S Sorghum, tons per acre S Sorghum, fresh wt dry wt Corn and Sweet Sorghum Yields in 2007 Pounds N per acre Corn

Sweet sorghum stalks, 2008 Fresh weight

Corn yields, 2008

Formerly Eastman Kodak Chemical Co. Batesville, Arkansas

Sorghum Stalks, 2007 ComponentLb Net Wt. % Water 26,03064 Sucrose6,45416 Glucose 4141 Fructose 3541 Unknown Water Extractables 2,3486 Bagasse 5,19913

Yeast conversion Sucrose + H2O  2 Glucose ,454 lb sucrose 6,794 lb glucose 2*180= 360

Yeast conversion Fructose + ½ O  Glucose lb sucrose 389 lb glucose

Ethanol for sugars As lb Glucose As lb Glucose Sucrose 6,794 Sucrose 6,794 Glucose 414 Glucose 414 Fructose 389 Fructose 389 Total 7,586 Total 7,586 Glucose  2 Ethanol + 2 CO GlucoseEthanol 7,586 lb x 2(46) = 3,877 lb 7,586 lb x 2(46) = 3,877 lb gal Eth/acre (theoretical) Based on 6.6 lb per gallon 0.511/6.6 = gal Et/lb glucose

Sweet Sorghum Bagasse Composition Wt. % Lbs Acid Sol Lignin 9489 Acid Insol Lignin 211,092 Arabinan4187 Xylan16811 Mannan>110 Galactan>142 Glucan442,293 Unknowns5276 “chem correct term for cellulose”

Ethanol from cellulose Glucan + H2O  Glucose 180/(180-18) = 1.1 lb glucose/lb glucan 2,293 lb x 1.1 x = 195 gallons glucan ethanol/acre from cellulose from cellulose Enzymes- currently too expensive H2OGlucose

Ethanol- loam soil Ethanol yield from corn with 160 lb N averaged 574 gal/acre Ethanol yield from corn with 160 lb N averaged 574 gal/acre Ethanol yield from sweet sorghum with 60 lb N averaged 528 gal/acre from sugar assuming 90% efficiency. Ethanol yield from sweet sorghum with 60 lb N averaged 528 gal/acre from sugar assuming 90% efficiency. Max including glucan= 782 gal/acre Max including glucan= 782 gal/acre Corn ethanol estimated 2.8 gal per bushel

Less Productive Soils Lb N ClaySand ClaySand Corn -bushels Sorghum- wet ton

Preliminary Summary Prime corn land should remain in corn production to supply food and feed. Prime corn land should remain in corn production to supply food and feed. Sweet sorghum niche for ethanol production may be on marginal soils such as heavy clay and sand. Sweet sorghum niche for ethanol production may be on marginal soils such as heavy clay and sand. Because of high cost of cellulose enzymes other uses for bagasse should be explored. Because of high cost of cellulose enzymes other uses for bagasse should be explored.