Sorghum Opportunities Rick Kochenower Dept. of Plant and Soil Sciences

Grain Sorghum Planting date Planting rate Fertility May have largest impact on yield Planting rate Fertility

Planting Date Rule 1 OSU recommends to not plant in May Utilizes rainfall from wettest period in Oklahoma

Grain Sorghum Water Requirement

Caddo County

Jackson County

Crop Water Use L.R. Stone

Water Use Comparison Crop Threshold Water Use (inches of water for first unit of grain)* High-Yield, Maximum Water Use (inches)* High-Yield W.U.E. (lb grain/ in. water, slope)* Low-Yield, Dryland Water Use (inches)** Low-Yield W.U.E. (lb grain/ in. water, total)** Corn 10.9 25 420 (7.5 bu) 13.9 186 (3.3 bu) Sorghum 6.9 21 353 (6.3 bu) 14.3 249 (4.4 bu) Average annual rainfall for western Kansas = 20.72 inches *Stone ** Aiken, Lamm, Gordon, Staggenborg 8

Planting Date Rule 2 keep flowering from occurring during the July 15 to Aug 15 period Keep flowering from occurring during generally the hottest and dries period in Oklahoma

Grain Yields Planting date Grain Yield bu/ac 2003† 2004 2005 Two-year April 1 75.2 80.6 74.1 77.4 April 15 60.3 67.9 61.0 64.4 May 1 47.5 46.1 39.0 42.5 * May 15 43.5 NA 40.8 40.8 * L.S.D. 13.5 18.0 7.0 6.4 † Note: Medium Maturity only * Bird damage Date 3 and 4: 56 and 55% respectively

2007 Performance trials at Homestead and Cherokee averaged 123.9 and 124.8 bu/ac respectively. Another study planted in May at Lahoma averaged 65 bu/ac. Performance trial at Altus averaged 89.9 bu/ac while another study planted in early May averaged 79.3 bu/ac

Seeding Rate OSU recommends a harvest population of 35 – 45,000 plant/ac Little higher or lower doesn’t hurt Performance trials have had over 100 bu/ac yields with 28,000 plants at harvest Germination for seed bag * the harvest population you want

Harvest Population 2004 Population Yield Heads/plant 20,000 49.9 1.94 30,000 70.5 1.68 40,000 74.6 1.22 50,000 78.9 1.08 60,000 82.0 0.84 70,000 88.4 0.91

Harvest Population Southwest 2007 Non tillering hybrid Tillering hybrid Yield Head/plant 30,000 87.4 1.44 90.9 1.95 40,000 92.9 1.18 95.1 1.50 50,000 93.4 1.11 1.28 60,000 93.8 0.99 94.0

5 plants in six inches equals 145,200 plants per acre or 9 5 plants in six inches equals 145,200 plants per acre or 9.7 lbs seed/ac

Grain Sorghum Fertility Nitrogen Yield goal * 1.2 -1.3 lbs N/bu of yield goal Sorghum performance trials soil test + applied fertilizer = 135 lbs N/ac 2007 sorghum yields reduced by not enough N Phosphorus Soil test

Coming soon Select Max tolerant sorghum New broadleaf herbicide Huskie Labeled on wheat now Research going on in 2007

oaes.pss.okstate.edu/goodwell/

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