Weed Control Planning
April 26, 2012
We’re still in the dead of winter, but Mississippi State University’s Rocky Lemus already is reminding cattleman to protect their pasture grasslands from runaway broadleaf infestation this coming spring.
Lemus, who joined the university’s staff of extension forage specialists seven years ago, urges producers to avoid the understandable temptation caused by other pressing early spring tasks to eliminate pasture weed control monitoring chores or cut corners by relying upon “drive by” scouting. He said producers can’t gauge the severity of weed infestation without thoroughly walking pastures throughout the growing season.
“One producer told me that he thought his broadleaf population was under control when he checked the pasture’s edges,” Lemus remarked. “But he was wrong. He returned three or four days later to discover severe weed infestation.”
Weeds Steal Nutrients
If highly competitive broadleaf weeds seize control, nutrition-rich grasses are crowded out, robbing grazing cattle of inexpensive and nutritious forage essential to achieving optimum performance. As a rule of thumb, research data reveal up to a pound of forage is lost per pound of weeds.
That loss comes at the expense of the producer’s profit margin, Lemus observed. Poor scouting or failure to pay attention to weed control can become a very costly issue. Data show a 450 to 500 pound calf can achieve around 800 pounds feeding on good pasture forages.
In warmer Southern regions where winter grazing exists, scouting is a year-around job. Elsewhere, cattle producers should regularly walk their pastures starting in early spring and continue until the first hard frost. Scouting fosters early detection of correctable environmental conditions that favor troublesome weeds.
Early Warning Protection
Early evidence of so-called “indicator” broadleaf plants can help identify looming weed control problems, much like coal miners once used canaries to guard against odorless and deadly gasses. Broom sedge plants, for example, provide an early warning of low pH conditions or fertility deficiencies that inhibit vigorous grass growth. Other correctible problems where weeds gain a critical toehold in early spring range from poor drainage to overgrazing.
Lemus, who earned his PhD from Virginia Tech, said pasture grasses require the right pH level. Therefore, he recommended that producers conduct soil testing in early spring and again in early fall. Furthermore, sample timing must be consistent to prevent skewing results due to different seasonal weather conditions. Lemus said producers can get by with soil testing once every two or three years in pastures, but hay fields should be tested annually due to higher nutrient removal.
If producers don’t control weeds in early spring, the undesirable plants will steal precious nutrients and moisture needed by pasture grasses and grazing cattle, leading to losing a season-long struggle. Lemus said 50-60 percent of summer’s pasture foliage is produced from May through July.
Either mowing or spraying herbicides provides another opportunity to halt encroachment of aggressive weeds this spring. If producers elect to spray broadleaf herbicides, Lemus stressed the need to be certain the chemical’s label permits forage application. If mowing is preferred, Lemus suggested that producers not clip shorter than four to six inches in height. Tall grasses can outshine competitive weeds by capturing sunlight while shading out normally shorter stature broadleaf weeds.
If time permits, Lemus said the seemingly endless winter months represent an excellent season to check and calibrate spray equipment, be certain you’re using the right nozzle pressure and map out your entire pasture weed control strategy.
“A producer can really benefit financially by having his equipment and plan in order now,” Lemus concluded, “and by getting off on the right foot in early spring.”
Source: Purina Checkpoint