Proper sorghum management increases yields
By Jennifer Carrico
Milo, or grain sorghum, is a warm-season grass that converts water to grain, similar to how corn does. But management of sorghum is very important in order to maximize yields, according to Bob Fanning, plant pathology field specialist with South Dakota State University Extension.
Fanning spoke to sorghum producers during Sorghum U, held in Mitchell, South Dakota, on April 3.
“The majority of the sorghum is grown in Kansas, Texas and South Dakota, but corn can push sorghum out where corn can be grown,” Fanning said.
Fanning said it’s important to select a key variety to plant based on soil and weather conditions. Maturity should be selected based on when a frost is expected or when moisture might run out.
“Later maturities have a higher yield, but they also have to have enough time to grow,” he said. “Later maturing varieties also have better stand ability and less lodging.”
Pest resistance is also a factor in selecting varieties. Yields increase by having more main stems and more seeds per head.
“If milo is headed out by Aug. 1, it should be a good crop,” Fanning said. “That way it avoids the extreme temperature changes that can have a negative impact on the grain yield.”
Seeding rates can vary depending on the area. Seeding rates are likely higher in South Dakota than in Kansas due to a higher rainfall. Emergence is expected at a 65 percent rate. At a rainfall of less than 20 inches per growing season, seeding rates can be as much as 37,000 seeds per acre. With a higher rainfall, of 20 to 26 inches, the seeding rate is increased to 54.000 seeds per acre.
“If we can increase yield with a higher seeding rate, it is worth looking at the cost versus profit numbers,” Fanning said.
Row spacing and seeding depth are important for emergence. Row spacing of 39 inches is common in planting sorghum, however, some producers drill seed or use air seeding, which makes the rows narrower. Ideal seeding depth is 1 1/2 to 1 3/4 inches deep.
Weed control and disease can cause havoc on the crop. Some diseases that affect sorghum are also harmful to corn. Fanning said it’s important to provide good growing conditions for the crop. Rotations of crops can help provide better conditions and herbicides should be used when needed.
Dwayne Beck, manager of the Dakota Lakes Research Farm near Pierre, South Dakota, suggested using no-till practices as a tool to improve sorghum production.
“We have been 100 percent no-till since 1990 at the Dakota Lakes Research Farm,” Beck said. “It has worked great for us.”
Beck said weeds become resistant because people provide the opportunity for that to happen by using the same herbicides year after year or planting the same crops year after year.
To get optimum yields, they place fertilizer in the ground when the sorghum and other grains are planted. This can improve the yield of corn up to 20 bushels per acre. Nitrogen and phosphorus is placed next to the seed, about 2 to 3 inches over from the seed at the same depth.
The residue left over from the previous year’s crop helps hamper the weeds from growing and once the canopy is established, it helps prevent weed growth also.
“We use crop rotation to help prevent weed problems. A two- to four-year break between crops can help prevention,” Beck said. “Weed resistance in corn country started because they were using the same herbicide year after year.”
Beck said crop rotation should be in a series that is complementary, for instance a simple rotation of winter wheat, sorghum and fallow or spring wheat, winter wheat, sorghum and then sunflowers.
Rotations can also be compound: spring wheat, winter wheat, sorghum, soybeans, sorghum and then soybeans. Some like a complex rotation of barley, winter wheat, corn, sunflowers, sorghum and then peas. Others prefer a stacked rotation of wheat, wheat, sorghum, corn, soybean and then soybeans.
“It takes a lot of experimenting to find the right rotation for the soil. The goal is to not allow an increase in pest population or weed population,” Beck said. “Good rotations will help prevent disease, weeds and pests.”
Sorghum is a good option for farmers who are in hotter, drier climates. Sorghum also has less insect pressure, the residue is easier to seed into and the seed costs less.
“I think we may even see some more sorghum grown in places that it hasn’t been grown in the past,” Beck said.
Jennifer Carrico can be reached by phone at 515-833-2120 or by email at firstname.lastname@example.org.