Weeds attacked at pesticide and pastures class

By MINDY POEHL | Central Texas Edition

Dr. Mark MacFarland, Extension soil fertility specialist, speaks about nutrient management programs for crops, at the Navarro County Pesticide Recertification Course held Feb. 1 at Navarro County Expo Center. Photo by Poehl -Staff photo by

Feb. 10, 2005 - Every year, each farmer and rancher who uses pesticides has the chance to renew their pesticide certification so they can properly use pesticides on their property. Sometimes, it seems like a nagging task. Other times, like this year, helpful speakers and interesting topics are chosen, making the recertification process a choice rather than a demand.

This year, Navarro County's pesticide recertification course took place on Tuesday, Feb. 1 at the Fannie Mae Vernon Room at the Navarro County Exposition Center.

Dr. Paul Baumann, professor and Extension weed specialist, spoke about weed management in pastures.

"We've gotta make weed pasture pay for itself," Baumann said. "As weed density increases, forage yield decreases."

The type of weeds to be controlled is a major consideration when selecting a herbicide product. The age and size of the plant can also determine the herbicide rate and its potential effectiveness. Baumann said to first figure out if the weeds are broadleafed, grasses, or sedges, and then identify if they are annual or perennial.

"Annual weeds have a limited root system and are easier to control than perennial weeds," Baumann said. "Perennial roots are underground storage systems that help them get from one year to the next."

Products that help to control perennial weeds are 2,4-D; Weedmaster; Grazon P+D; Fuego; Redeem; Rave; Cimmarron and Amber.

Herbicide treatments are most often used for broadleaf-type plants because they "have significant soil activity on grass and broadleaf seedlings," Baumann said.

Proper timing of a herbicide application should be based on the stage of weed growth, potential risk to nearby sensitive crops, and environmental conditions, such as air temperatures and humidity.

"The best time to control annual weeds is to get them early," Baumann said.

Newly seeded forage grasses can be injured if herbicides are applied before or soon after a new pasture renovation. In general, annual broadleaf weeds are easier to control when herbicides are applied to plants that are small and actively growing. Perennial broadleaf weeds tend to be most susceptible when plants have reached the early bloom stage of growth.

When applying herbicides Baumann said to be aware of herbicide drift. "The movement of the substance goes away from the intended target," he said.

Drift reducing additives are polymers and encapsulators. Uncontrollable conditions when applying herbicides are the temperature, wind direction, humidity and air stability.

"What you can control when applying herbicides is the drop size. That is the most important factor," Baumann said.

A new, noxious, invasive perennial weed that is found in Texas, and that Baumann warned about, is Tropical Soda Apple (TSA). Baumann said products like Grazon P+D, Remedy, Tordon 22K and Surmount will provide top kill for TSA, but "do not get it mixed up with Horsenettle."

Finally, Baumann compared shredding weeds to using herbicides. He found that herbicide is more expensive by $3 difference per acre.

Archie Abrameit, Stiles Farm manager in Thrall, was also on hand where he addressed strip tillage for the Blacklands.

"I do not encourage a strip till now," Abrameit said. "The soil is too loose. I suggest doing it in October or November. That is the ideal time."

Abrameit showed slides of different planters. He said a spoke wheel applicator is good for a starter fertilizer. The spokes push the fertilizer into the ground and it is good to use when the ground is wet.

Abrameit summarized saying, "A reduced till system leaves a lot of residue. But, if you slow down, you might just see better results."

Dr. Mark MacFarland, Extension soil fertility specialist, said it was important to measure the nutrients in soil. For intance, input costs include fertilizer, equipment, fuel and seed, which will create the optimum yield and crop quality, he said.

"Be good stewards and manage nutrients and nitrogen and phosphorous," MacFarland said. "A very good way to manage nutrients is by a soil test. It identifies if the soil nutrient is deficient, sufficient or excess."

Phosphorous goes through a stratification process. It does not leach as long as the soil is wet.

"Nitrogen doesn't get away as much as we think it does," MacFarland stressed. "That is why it is helpful to do a soil test."

Dry phosphates also fertilize soil. When it rains, the water is washed into holes in the soil. Livestock manures, biosolids, compost and cover crops/green manures, like legumes, are alternative fertilizers.

"Make sure fertilizers are in a uniform application, at the correct rate in an even distribution," MacFarland concluded.