Some cattle producers are overstocking and intensively grazing pastures as cattle destined for market were derailed as processing plants shuttered over COVID-19 concerns. Now these farmers face a growing concern over the lack of forage in the coming months.
One option to boost feed production is to plant sorghum sudangrass, says Tim Schnakenberg, University of Missouri Extension agronomist. Farmers can seed this warm-season grass from May through June, but be careful of soil temperatures.
“Don’t get in a big hurry,” Schnakenberg says. “We consistently need a soil temperature of 65 degrees or better.”
He adds that sorghum sudangrass is not like crabgrass, bermudagrass or clover that can be sown and will wait until the temperatures warm to grow. “You don’t want (sorghum sudangrass) to go through a warm spell, germinate, then come up and get cold again,” he says. “You may not be happy with the stand you get if you jump a little too early.”
Backstory on sorghum sudangrass
According to a MU Extension guide on warm-season annual forages, sorghum sudangrass is a hybrid developed by crossing forage sorghum with true sudangrass.
It can be confused with forage sorghum, or milo, to many onlookers. Unlike milo, which is a short plant that produces seed, sorghum sudangrass grows tall and is comprised only of leaves and stems.
Sorghum sudangrass does not grow well in soils with low pH. It requires a pH above 5.5, which makes it adaptable to most areas of Missouri.
How to plant
Before planting, consider using a burndown herbicide application if there are competition plants in the field.
Seeding rates depend on method and money. Broadcasting sudangrass is best at 30 to 40 pounds per acre, Schnakenberg says. For those farmers who prefer to drill, a rate of 20 to 25 pounds per acre provides quality stands. If drilling, the preferred seed depth is a half-inch to 1 inch in 7- to 15-inch rows.
“Farmers in southwest Missouri will typically sow at rates higher than that,” Schnakenberg adds. “If you’re willing to pay the expense, it will increase forage production.”
Sorghum sudangrass needs fertilizer, so Schnakenberg recommends putting down 40 to 50 pounds per acre of nitrogen at planting. He says farmers should add another 30 to 50 pounds at cutting or grazing.
When to graze sorghum sudangrass
Most of the production of this warm-season forage happens from June through August.
Cattle producers can start grazing once plants reach 2 feet. Grazing below that threshold may result in prussic acid poisoning.
For farmers wanting to use the extra forage as hay, it is best to wait for cutting until plants reach 30 to 36 inches tall. However, if forage supplies run short, it can be cut at 10 inches or above.
Bottom line, if you are looking for a filler forage, sorghum sudangrass can provide the nutrition needs to maintain cattle during the summer months or until they ship to packers.