With the drought, overgrazing of pastures this summer, and out-of-state hay being fed this winter, this all adds up to be the perfect environment for an extraordinary weed infestation in 2012.
Identifying these weeds is the first step with control.
Let's start by answering this question: What is a weed? Perhaps the best definition of a weed is a plant out of place, a plant that is growing where you don't want it - this could be in a pasture, garden or lawn. Not all weeds are bad, just undesirable - like sunflowers in a cornfield are considered weeds to a farmer, as is Bermuda grass in a vegetable bed to the gardener.
Weeds can be grouped into two major categories, grasses and broad leaves. Weeds can compete with pasture grasses for water, nutrients and sunlight. They can also harbor insects and plant diseases. Some weeds are toxic and can cause livestock to become ill or die.
Weed seeds can remain dormant in the soil for many years, and then germinate when conditions are right. When weeds appear, they can be controlled by many different methods.
Prevention can be accomplished by planting weed-free seed or using a pre-emergent herbicide. In worst cases, eradication of the invasive weed may mean complete re-establishment of the pasture.
Other control methods may involve limited use of herbicides, cultivation, mowing, or maintenance of a vigorous pasture grass that will crowd out weeds.
Mowing weeds with a rotary mower can be risky - it usually causes the weeds to produce their leaves closer to the soil. If you decide to mow, it should be done when weeds are in the bud or pre-bloom stage to reduce seed production of the invasive plant.
If a herbicide is used, you must first identify the plant to be controlled in order to choose the right chemical. Herbicide application rates will vary by weed species and plant maturity.
Some herbicides containing 2-4D as the active ingredient require a pesticide applicator license to purchase and apply. When using chemicals, it is very important to read the label and follow the directions closely, to prevent injury to livestock or humans or damage from spray drift.
Federal and state laws control the use of restricted and state-limited herbicides.
General-use herbicides - such as Roundup, PastureGard, Cimarron and Redeem - do not require a license and will do a good job on selected weed varieties.
Pasture weed control will increase forage production on the average of 1 pound for every pound of weeds controlled. This increase can be equivalent to the application of 40 to 60 pounds of nitrogen per acre.
The best method of weed preventive control is to maintain a healthy and well-fertilized stand of pasture grass.
EDDIE BAGGS, extension agent with the Texas AgriLife Extension Service in Denton County, can be reached at 940-349-2880.