With late planting of corn now a given and more than the usual amount of alfalfa winterkill, this might be a year to think about planting summer annuals such as sorghum and sorghum-sudangrass hybrids. Their versatility and preference for early summer planting can help bolster grazable or stored forage inventories.
“Adding a summer annual forage to available acreage can help fill forage needs, add grazing flexibility, and provide a drought tolerant forage,” Travis Meteer writes in a recent The Cattle Connection blog from the University of Illinois-Extension. “While utilizing tillable acreage for summer annual forage production is an option, consider areas that may have been heavily abused from winter feeding or sacrifice paddocks that may benefit from the natural weed control of a competitive summer annual stand,” adds the extension educator.
Grazing and haying
Meteer notes that sorghum-sudangrass has proved its worth both as a grazing and multi-cut hay crop. For grazing, it’s usually ready to put animals on six to eight weeks after planting, or when plants are 18 to 24 inches tall. The educator emphasizes to leave about one-third of the plant as residual, or at least 8 inches.
As has been often documented, sorghum species can be a prussic acid risk when stressful environmental conditions exist such as a frost or when immature plants are overgrazed. Where high nitrogen fertility is present or heavy manure applications have been made, forage nitrate levels also need to be monitored.
If haying sorghum-sudangrass, Meteer says to wait for a flag leaf to develop. As with grazing, leave a 6- to 8-inch stubble to allow for vigorous regrowth.
“Limited forage supplies, poor pasture productivity, and drought management are all good reasons to consider planting a summer annual forage,” Meteer says. “With careful management, summer annual forages can be a valuable component to solving forage inadequacies.”
As an emergency forage or simply a cost-effective alternative to corn silage, sorghum seems to be gaining momentum even in more humid regions of the northern United States.
“With some corn hybrids topping $350 a bag or $140 per acre, BMR (brown midrib) sorghum at 10 pounds of seed per acre is only about $20 per acre (to plant) — a direct savings of $120 per acre before the crop is even planted,” writes Tom Kilcer in his latest issue of Crop Soil News.
Kilcer, who is an independent crop consultant based in Kinderhook, N.Y., has been doing extensive research with sorghum as a fit into various cropping systems.
Even in years not characterized by late planting like the current one, Kilcer promotes a rotation of sorghum followed by a winter annual such as triticale, then followed again by sorghum or no-tilling the field into alfalfa. Either of these alternatives can be seeded in early June.
“Drill on 15-inch rows to optimize yield and to shade the ground,” Kilcer suggests. “The most critical step in establishing sorghum is to wait until the soil is 62 to 65°F at a 1-inch depth. Sorghum seed can be planted at 3/4 to 1-inch deep and fertilized similar to corn,” he adds.