Forage sorghums can help provide feed in regions short on forage after last year’s droughts, say university agronomists from Pennsylvania and Texas.
Greg Roth urges south-central Pennsylvania dairy producers to consider doublecropping brown midrib (BMR) forage sorghums – after first-cut hay or small-grain silage – on ground some are currently putting to silage corn.
“As our dairies are expanding and trying to grow forage, they’re expanding on soils that are not ideal for corn production,” says the Penn State University agronomist. “They tend to be shallow soils that can grow good small grains, but they’re prone to drought in the summer.
“So on those soils there might be a fit for forage sorghums. They tend to be lower cost for establishment, can be doublecropped with a small grain and tolerate a little later planting than corn.”
Water shortages have made forage sorghums popular with Texas dairies. This year they will be even more so, says Brent Bean, Texas AgriLife Extension agronomist at Amarillo.
“We’re going to see a definite increase this year in forage sorghums over corn. Last year with the drought we had in the Texas Panhandle, which was unprecedented, a lot of corn acres ended up having to be abandoned just because they didn’t have the water to irrigate them.
“So people are cutting back some on corn silage in favor of forage sorghums because forage sorghums require less water and can span periods of drought without dying like corn will,” Bean says. “We’ve been preaching quality for a long time on forage sorghums, but because of the drought and the shortage of hay and silage, people are just looking for tonnage.”
Seed representatives in his area, he says, are nearly sold out of forage sorghum seed.
Roth has researched conventional forage sorghums for years, although lodging and poor fiber digestibility have limited their use. The newer BMR forage sorghums are more digestible and some now offer the brachytic dwarf trait, he says.
The trait produces a compact plant, adds Bean, and “it’s supposed to stand up a little bit better and not lodge, although I haven’t seen that. It looks impressive in the field – it’s very leafy. But I think the jury is still out on it.”
“It’s very lodging-resistant,” says Roth, who last year compared varieties with the trait to medium-height conventional and BMR lines as well as tall, high-yielding biomass energy lines.
“One characteristic that we looked at was the 30-hour NDFD (fiber digestibility). We were getting values of 54-59% with the BMRs and 45%- with the conventionals,” he says.
BMR forage sorghums yielded 15-20 tons/acre on a 35% dry matter basis during droughty growing conditions. Corn yields in the area averaged about 10 tons/acre.
“In a good year, sorghum yields could be in the 17- to 25-ton range depending on moisture,” Roth says. “I’m still a big fan of corn silage; that’s the backbone of our forage program. But a good role for these forage sorghums is on shallower soils. And they are a great way to utilize excess manure nutrients.”
Producers should work with seed dealers to find sorghums well adapted to how they will be used. In Pennsylvania, Roth suggests planting the crop in late May to avoid slow fall drydown and managing it as if it were corn. Control weeds and fertilize as needed, he says.
Blend forage sorghum with corn silage in rations for high-producing dairy cows, Roth advises.