If you’re trying to grow corn silage on drought-prone soils or where irrigation is an issue, forage sorghum types are worth consideration, says Robert Lemon, an agronomist with AgriThority.
|Forage sorghum can compete with corn, according to agronomist Robert Lemon.
Lemon spoke Sunday at an AgConnect
Dairy Seminar here in Atlanta.
“It’s all about forage palatability, digestibility and making milk,” says Lemon. “Yields of [new variety] sorghums are comparable to corn, and in some cases, superior to corn. Forage sorghum is very tolerant of heat; it is very tolerant of water stress.”
Lemon notes that forage sorghums can yield similar to corn with 30% to 50% less water. One acre inch of water will produce 1.75 to 2.5 tons of sorghum forage dry matter compared to just one ton of corn silage. “Sorghum plants don’t do this magically,” he adds. They have a waxy coating on their leaves that prevent water loss, and sorghum leaves roll up under drought condition.
But the plant’s heat tolerance is key. Their optimal growth temperature is 86ºF, and will still continue to photosynthesize at temperatures above 100ºF.
New dwarf varieties, known as Brachytic dwarf sorghums, produce comparable tonnages to normal varieties. But they are less prone to lodging and have a very high leaf-to-stalk ratio.
When combined with Brown Mid-Ribbed varieties, they make a highly digestible forage alternative.
Lemon notes that sorghums due have their concerns. They can be a source of prussic acid poisoning and nitrate toxicity under high environmental stress. “These are not a reason not to grow them. You just need to be aware of these concerns and manage for them,” he says.