Tips to maximize sorghum yields

Is 200 bushels per acre (11,200 pounds per acre) grain sorghum possible? Many producers would say no, but it has been done.

I recently attended the National Grain Sorghum Producers Association meeting where national yield contest winners were announced. The top yield in the 2004 yield contest was an amazing 213 bushels per acre. Four producers had yields over 200 bushels per acre.

The yields illustrate that with proper management and good growing conditions, grain sorghum is capable of producing extremely high yields.

High-yielding grain sorghum begins with a balanced fertility program. Follow soil test recommendations for phosphorus, potassium, sulfur and zinc. Supply adequate potassium to maintain stalk quality prior to harvest and reduce charcoal rot. The nitrogen rate depends on whether the crop is grown dryland or irrigated. Apply 100 to 120 pounds of actual nitrogen per acre on dryland sorghum and 150 pounds on irrigated sorghum. Apply one-third of the total nitrogen preplant and the remainder sidedressed by the six-leaf stage.

Planting date is very important. Plant early enough to take advantage of soil moisture during May and June and to develop the crop before the heat and drought of July. Planting early also reduces sorghum midge damage, a very serious problem on later-planted grain sorghum.

However, planting too early can also cause problems. Grain sorghum is not tolerant of cold wet soils and poor stands can result. In Arkansas, April is a good month to plant sorghum while March is too cold and wet most years.

Planting grain sorghum into cool wet soils will stress a young seedling, said Ken Smith, University of Arkansas Cooperative Extension weed scientist. The stress and grain sorghum's low tolerance of atrazine early in the growing season can lead to problems, especially when a full atrazine rate (2 pounds per acre) is applied pre-emerge.

“To reduce the risk of atrazine injury, I would like to see producers using metolachlor plus 0.75 pound per acre of atrazine applied pre and followed by 1 to 1.25 pounds per acre of atrazine plus a crop oil postemergence,” Smith said. Concep-treated grain sorghum seed is a must.

Hybrid selection and plant population are critical for high yields. When choosing hybrids, look closely at two-year and three-year yield averages to see how hybrids perform. The University of Arkansas grain sorghum testing program has multiple year yield averages for many hybrids. Visit the University of Arkansas Cooperative Extension Web site: for more information.

The best plant population will depend on whether the field is dryland or irrigated. For dryland fields, plant populations of 50,000 to 60,000 plants per acre can result in high yields, while irrigated fields should have around 75,000 plants per acre. Assume that 80 percent of the seeds planted will emerge. Also, plant seed treated with Gaucho or Cruiser to protect against early-season insects.

There are many sorghum diseases in the South, the most important being anthracnose. “Select a high-yielding hybrid with resistance to anthracnose to minimize this risk,” said David TeBeest, University of Arkansas professor of plant pathology with the University of Arkansas Division of Agriculture. “Our research has shown that harvesting sorghum promptly when ready will maximize yield and quality and minimize the effect of this and other late-season diseases.”

Balanced fertilization, high-yielding but disease-resistant hybrids, optimum planting date and seeding rate, insecticide seed treatment, good herbicide program, and timely harvest should maximize grain sorghum yield potential on your farm.

Jason Kelley is the Arkansas Extension agronomist for wheat and feed grains.

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