Weed or Forage

By Clay Coppedge
DTN/Progressive Farmer Contributing Editor

No matter how good the forage program, every operation has, at times, had to think outside of the box to feed the herd. Maybe it was drought or a poor production season that caused it, but there are times the traditional grasses like bermuda, fescue or alfalfa don't stand up to the test.

That's when something like crabgrass can start looking pretty good. Or Johnsongrass. Or bahiagrass. Or switchgrass. But all of these grasses offer challenges; some can even be poisonous under the right conditions.

Vanessa Corriher-Olson uses crabgrass as an example: "Most of us know crabgrass as a weedy plant, but it's a relatively high-quality, summer annual forage when most summer perennial forage is low quality. It forms a good sod, and it can also provide a complete ground cover," said Corriher-Olson, a forage specialist with Texas A&M AgriLife Extension Service.

CRABGRASS

James Rogers, forage specialist with The Samuel Roberts Noble Foundation, a nonprofit agriculture research institute in Oklahoma, agrees crabgrass has potential as a forage. He said it can be especially effective when double-cropped following cereal grains like rye or wheat.

"You can turn summer stockers into it early, and it can be a real good forage. You can get some good stocker gains with it," Rogers said. He added it responds as well to nitrogen as bermudagrass, and quality is higher.

Studies by The Noble Foundation show well-managed crabgrass can be 25% to 30% crude protein (CP) in its first growth cycle, with a drop-off in CP (15% to 20%) in its midsummer regrowth cycle. It scores 10% to 15% higher in digestibility than bermudagrass, a relative difference of up to 25%.

Corriher-Olson said crabgrass adapts to many soil types but prefers well-drained sandy loam, sandy clay loam or clay loam soils. She recommended cutting it for hay in the boot to heading stage (normally 18 to 24 inches high), but noted it usually cures more slowly than bermudagrass. That can make it a poor fit in a bermudagrass hay meadow. Another drawback is it's an annual plant, so growers who want to make it a regular part of their grazing program must manage it for reseeding.

To establish crabgrass, Corriher-Olson said to plant in the spring on a clean, fresh seedbed after the danger of frost is past. Plant seed at 3 to 5 pounds per acre (ppa). The first harvest of the year yields the best hay, sometimes containing more than 15% crude protein and 60% total digestible nutrients (TDN).

JOHNSONGRASS

It may surprise some producers to hear that Johnsongrass also has its positives. It ran neck and neck with bermudagrass in terms of CP and TDN in a study by The Noble Foundation, with 10% to 14% CP and 55 to 60% TDN.

Johnsongrass is fairly drought tolerant, and cattle will seek it out when it's relatively immature. The caveat when it comes to Johnsongrass is that it can accumulate nitrates, which produce prussic acid after stressful conditions, such as drought, freezing weather or exposure to herbicides that kill grasses. For at least a week after it's been subjected to any of these conditions, cattle should not be allowed in those fields, as it can be fatal. Producers interested in allowing cattle to graze Johnsongrass should have it tested to be sure it's safe.

BAHIAGRASS

Another warm-season perennial, Bahiagrass, can be valuable as a pasture grass.

"Bahiagrass tolerates a wider range of soil conditions than bermudagrass," Corriher-Olson said. "It's established by seed rather than sprigs, resists encroachment by weeds and can persist and produce moderate yields on soils of low fertility. It also withstands heavy grazing."

Bahiagrass grows well in upland sandy areas and even on poorly drained sandy areas. It can be used as permanent pasture or as a hay crop. Planting rate is 15 to 20 ppa broadcast into a prepared seedbed. Corriher-Olson says as hay, it has 50% to 56% TDN and about 10% CP if cut on less than five-week intervals.

SWITCHGRASS

A few years ago, switchgrass was being looked at as a potential biofuel crop, but now it's getting attention for its forage potential. Rogers said work is ongoing as to its value for cattle producers, but he added it produces grazable forage earlier in the spring than bermudagrass, and quality is good, with CP levels that average 5.9% and TDN at 53.8%.

Switchgrass should be seeded in a pure stand, though it may be mixed with native grasses, forbs or legumes, Rogers said. Drill seed at 4 to 6 ppa in a pure stand, or broadcast the seed at 8 to 10 ppa. When drilled, seeds would be planted ¼ inch deep.

"One drawback is when you get into July, the quality deteriorates," Rogers said. "You get a lot of forage mass, which is a good thing in the spring; but in the summer, you can end up with too much low-quality forage."

FESCUES

Some tall "Mediterranean-type" fescues can go dormant in the summer, Rogers said, but by early fall, they provide good fall and winter grazing. The Noble Foundation is researching these summer-dormant type tall fescues for their ability to provide perennial cool-season forage production along the I-35 corridor from Oklahoma City into Texas.

"It's a good-quality forage," Rogers stressed. "It responds well to a little bit of nitrogen. It can easily have a CP level [of] about 10% in winter."

Another fescue, named "Hidden Valley" meadow fescue for the farm where it was found, is a mostly forgotten forage grass imported from Europe in the 1800s by European settlers. A Wisconsin farmer found it on a shaded hilltop pasture that neither he or anybody else had ever seeded with commercial forages. The cattle didn't care how it got there, they thrived on it and spread it by dropping ripe seeds in their manure.

The farm contacted Michael Casler and his colleagues at the U.S. Dairy Forage Research Center, in Madison, Wis., to find out what kind of grass it was. Casler ended up studying Hidden Valley for 12 years.

Higher-yielding tall fescues and other grasses crowded it out of most pastures by the 1950s, but patches survived in the Driftless Region, part of the country never "glaciated," including northwest Illinois, northeast Iowa, southeast Minnesota and southwest Wisconsin.

This grass is similar to tall fescue but with higher fiber digestibility and cold tolerance. Casler said CP and TDN averages are not available, but it does not produce the toxic alkaloids found in tall fescue.

"It's a fantastic grass," Casler said. "It's drought tolerant, cold tolerant and high in digestibility." He expects seed for Hidden Valley to be on the commercial market in 2017. "It works really well in a rotational system," he said. "You have to rest it a bit. It won't stand up to continuous grazing."

(VM/CZ)

Copyright 2016 DTN/The Progressive Farmer. All rights reserved.