Making room for more grass
By Alan Newport

Weed control had long lasting effects for grazing on this farm

David Schapeler had always done brush control on his Appleton City dairy farm with a mower, but 2 years ago he learned a new trick.

MFA dairy specialist Archie Devore visited him and suggested a good spraying of Schapeler’s pastures would pay dividends. Schapeler can’t recall exactly what Devore said that convinced him, but he decided to try it.

The fescue pasture where his cows are turned out between milkings nearly every day of the year was the biggest issue. It was burdened with a variety of problem plants, including pigweed, ragweed and buck brush … and their numbers were growing. About a fourth of the 55- or 60-acre pasture, a portion on the west side of a creek, was the worst, Schapeler said. Sometimes he couldn’t even see the cows when they were in that area.

In the spring of 2004, he called nearby MFA Bolivar Farmers Exchange and had that pasture and another one treated. The dealer used a combination of Grazon P+D and 2,4-D LV, applied at the rate of 1 quart each per acre. The tank mix included 1 quart Astute (a wetting agent) in 100 gallons of water, which was applied at the rate of 20 gallons per acre. Such a mix requires certain grazing restrictions. For example, dairy cows can’t be on Grazon/2,4-D-treated pasture for 7 days. It is important to understand the label, and follow its directions.

At first, Schapeler was skeptical. Many of the brush species stayed green for weeks afterward. But the weeds and brush in the pastures kept shrinking and the grass kept getting better.

“The thing that’s amazing is just how much more grass I have now,” Schapeler said recently, nearly 2 years after the treatment. “My wife was complaining that in the first year she couldn’t get across the pasture on the four-wheeler when she took the cows out. The leaves on the plants were 14 to 18 inches long and it was all matted up as deep as your knees.”

The other pasture was 80 acres of fescue. On that parcel, Schapeler and a neighbor have fought thistles for years, cutting and spot spraying.

“We never could get ahead of them,” he said. “But the spray got them all—I think I had only one thistle survive.”

Schapeler’s pastures get good use. He runs about 80 cows on the 55 to 60 acres all year, but only for 6 or 8 hours per day. Further, he fertilizes yearly and follows fertilizer and lime recommendations from the soil samples he takes on a 5-year schedule.

“I’m no expert on herbicides,” he said, “but I’m learning some things.”

First, said Schapeler, he has decided the cost of a well-applied herbicide treatment is actually an investment.

“It cost me some money out of my pocket, but it’ll make you money and save time,” he said.

The high cost of fertilizer these days makes growing grass instead of weeds increasingly important, Schapeler added.

Second, setting the weeds back has long-lasting effects. “The more grass you have, the fewer weeds you’re going to get,” Schapeler said.

Third, don’t be impatient after a weed treatment. It takes some time for the effects to become visible.

Fourth, your weed problem may require another treatment sooner than you want.

Fifth, he has seen a decrease in erosion along the creek bottom and the pond banks because the ground there is now better covered with forage.

Last, Schapeler said to consider potential herbicide damage to clover or ryegrass as part of the decision process. “You’ve got to decide whether you’ve got enough clover that you don’t want to kill it and whether the weeds are hurting you that much. I didn’t have much clover so it wasn’t a difficult decision for me.”

Weed control is timing

If you want effective chemical weed control you need to identify the problem plants and know something about their life cycles.

That’s because most herbicides work best when the plant is actively “translocating,” or moving, carbohydrates throughout its parts, including into the roots, said Kevin Bradley, state extension weed scientist for the University of Missouri.

Generally, weeds are classified as annuals, biennials or perennials.

Most plants are controlled best before they enter the reproductive stage, Bradley said.

There are many nuances to effective herbicide usage, but here are some guidelines.

Annuals are best controlled when they are young and actively growing. Control winter annuals in fall before the plants over-winter, or early in the spring before the plants start to flower.

Summer annuals germinate in the spring and complete growth by the fall. They are best controlled in the spring or early summer while very small—always before flowering.

Biennials live no more than 2 years and reproduce only by seed. These plants often germinate in the fall, and for their first year grow as a rosette close to the ground. Sometime in the second year of their life cycle, biennials undergo rapid stem elongation and flowering and then set seed. This stage is not the time for optimum herbicidal control.

A great time to control biennials is in the fall. The new plants are emerging and the 1-year-old plants are still in the rosette stage, said Lyndon Brush, MFA staff agronomist. Alternately, spraying in early spring can help control the young plants that germinated last fall, but it must be done before the older plants reproduce.

Perennials may live for several years, reproducing from seed and/or through roots and rhizomes. Good control of these weeds is difficult, but the best time is when the plants initiate bud stage and begin to build root reserves. Choose herbicides that translocate to plant roots. Seedling plants in their first year of growth can be sprayed prior to bud stage.

Think about clover

When you choose a herbicide, consider the long-term effects on clovers.

“Whatever you spray, you’re going to kill at least some but usually all of your clover,” said Kevin Bradley, University of Missouri  extension weed scientist.

The less obvious issue, however, is the persistence of the herbicide you choose to treat your pastures, he said.

“With certain herbicides, you can replant clover in the same year, but the more persistent ones like Grazon P+D may require a year or more before you can safely replant clover,” he said.

“Weed and Brush Control Guide for Forages, Pastures and Noncroplandr” may be used to select and compare herbicides and may be ordered from the University of Missouri via this website: http://muextension.missouri.edu/explore/miscpubs/mp0581.htm