Interseeding cool-season annual grasses into bermudagrass is a common practice from the Deep South into Oklahoma. By doing so many producers expect to be able to graze the annuals in mid-March like they would with a small grain type field.
“Programs where we're trying to grow a compatible third species to extend the grazing season can be management-intensive,” said Paul Beck, University of Arkansas Extension animal scientist, at the recent field day the Livestock and Forestry Branch Station in Batesville, Ark.
“We're trying to keep production high on the bermudagrass while also trying to get good production from winter annuals.”
Beck has been working with interseeding small grains and ryegrass into bermudagrass for the last five or six years. In some research around his base of Hope, Ark., he's worked with an economist.
“When all costs were added up — fertilizer, tractor costs, whatever — interseeding a small grain component only costs about $112 per acre. That isn't much different than what you'd expect with a crop field planting.”
Ryegrass in the mix adds about $8, for a total of $120 per acre.
“On top of that, fertilizing ryegrass to push growth in late spring adds another $20. So, total, it'll cost about $140 per acre to interseed ryegrass and small grains.”
If cattlemen are going to do this, they “must push production and get as many grazing days as possible. We expect to get cattle on pastures no later than the first of January — about two or three months earlier than normal.”
A no-till drill allows good seed-to-soil contact. Around Hope, in southwest Arkansas, “we try to plant small grains in mid-October because we don't want the bermudagrass to compete with cool-season annual seedlings. If there's competition for light and moisture, usually the perennial wins.”
When planting in mid-October, Beck usually waits for the cool-season annuals to emerge and get a bit of growth — two or three leaves — before applying fertilizer. He then applies about 300 pounds “of triple-17 or a blended fertilizer. That's because most of the time in these bermudagrass pastures most phosphorus and potassium have been bound up and nitrogen has been used up.”
That's one of the big differences between Beck's research and producer situations. “We fertilize to push for fall growth. At Hope, in two or the last five or six years, we were able to begin grazing in January or February. The other years, we were able to begin grazing the first part of December.
“Another thing we've done for the last couple of years is apply low rates of Roundup — a pint per acre — to bermudagrass in the first part of September.”
Doing so “kind of forces” the grass into dormancy. That allows researchers to plant the annuals about a month early.
“Whenever we look at crop fields or dedicated fields for grazing, the key to achieving early fall growth is to use the earliest planting date possible. That extra month to establish grasses really helps.”
The fall before last, Beck had two planting dates. Where he planted in September, “we were able to get the cattle on the grass in early January. Where we put Roundup out on early-planted wheat, we got about an extra month of early grazing. We had a very spotty stand where we didn't put out Roundup. We sprayed and planted between the two hurricanes.”
Where Beck didn't spray, the second hurricane's rain came through. All the crabgrass and bermudagrass came back and shut out about half the stand of wheat and small grains.
“You really can't have the early planting date without a Roundup application.”
There's also been a stocking rate and supplementation trial for the last three years. The second year of the test, grazing began in March — “a pretty bad year. We were fighting Mother Nature. If we don't have forages established, we don't have grass in the fall.”
For the two years he was able to get early grazing, the stocking rates for the calves were approximately 2 acres per calf. That's compared to about 1 acre per calf on dedicated crop fields. So production in the fall “is a bit lower than what we expect to see when not interseeding bermudagrass.”
Then, in the spring, stocking rates are about the same. “I've found that small grain plants in the spring, when you start getting temperatures and rainfall, are difficult to keep from growing.”
Most cattle producers in Arkansas are in cow-calf work. Beck does most of his work with stocker cattle, “but these results can be applied to cow-calf production.”
“When we look at this set-up, we're normally talking about stocker cattle, but we can make some applications to cows. One of those is the cost of establishing.”
To support the continuous grazing of a cow herd, a producer needs about 100 acres for a 25- to 30-head herd through the winter. “Of course, in the spring, when the plants begin growing, we won't need nearly that much.”
For the last eight years, Beck has also studied a limit-grazing program. “That's where we have 25-head herds on 18 acres of pasture. Twelve acres have a warm-season grass base with 6 acres in a winter annual, or over the last four years, a novel endophyte fescue.”
The herds calve in the spring. So during the fall when cows don't require a lot of extra nutrients, “the growth of our small grains or novel endophytes is also low. We'll provide low-quality hay for those dry, pregnant cows. And we turn the cows onto the pastures once or twice a week for eight-hour stretches.”
When cows begin the third trimester of pregnancy and early lactation, “we begin increasing the access cattle have to the small grains. That corresponds to the increase in forage production from those pastures.”
Six acres per 25 cows “really works out to be the correct stocking rate. With that program, we're decreasing hay consumption 15 to 20 percent. And when you include the costs of establishment, fertilizer and other associated costs, we pencil out savings of about $25 per cow through the winter.”
Another thing that can apply to a cow-calf operation, especially if heifers are being retained, “is if you plant enough small grains to get the heifers through the winter — 2 acres per heifer — by the time it begins growing again, you'll have wheat forage or other cool-season grass available for the cow herd.”