Cooler spring didn’t stop weed flushes — only delayed them
Producers who neglected early season control of annual weeds such as this yellow bitterweed lost an inch or more of moisture their pasture grasses could use now due to competition, according to a Texas A&M AgriLife Extension Service expert.
COLLEGE STATION -- Farmers and ranchers who passed on controlling slow-growing weeds this spring may now have reason for regret, said a Texas A&M AgriLife Extension Service expert.
“If you’re standing out in your hay meadow or pasture and wish you had another inch of rain, that inch of rain may have been that which was sacrificed to early season weed issues,” said Dr. Paul Baumann, AgriLife Extension state weed specialist, College Station.
The cooler-than-usual spring slowed the growth of weeds and warm-season grasses alike, and many producers may have put off spraying or shredding weeds, Baumann said. But now that the drought is re-strengthening in nearly all of Texas, many weed species are coming back with a vengeance, robbing improved pasture grasses of moisture and nutrients.
Weeds that always pose early season competition for improved forage grass areas of Texas include annual broomweed, wooly croton, goat weed, bitter sneezeweed, and a number of other annual weeds, he said.
Many perennial weeds that flourish during a drought are troublesome but usually don’t pose as much as a challenge to improved pastures as the annuals, according to Baumann.
“For the perennials, we’re talking about silverleaf nightshade, dog fennel, horse nettle, Texas bull nettle, and weeds like that,” he said. “They flourish because they have a well-developed, deeper root system that makes them less prone to moisture deficiency, particularly in the lower soil profile.”
But the early season annuals like goat weed, dove weed, or wooly croton have shallower root systems that vie for the same shallow soil moisture that Bermuda grass and other improved pastures are trying to capture, he said.
For producers who did not do any early season weed control and are now seeing a flush of annual weeds in their pastures, Baumann recommended waiting until a good rain before doing anything.
“For the weeds that are still out there that are less than 6 to 8 inches tall, wait until you get a little bit of rain on them before spraying because they are going to be less susceptible to herbicide if they are moisture stressed,” he said.
Leaving weeds uncontrolled, even if there is not much grass growth, is not a good choice, Baumann said. This is because they are going to continue to compete for moisture during a very stressful time of year, as well as eventually deposit a seed load that will last for years to come.
Also, if there is a mid-season rain, the weeds will spring back to life and compete with pasture grasses at a very critical time of year, he said.
AgriLife Extension district reporters compiled the following summaries for the week of July 1-7:
AgriLife Extension district reporters for the Southwest District, including Wilson, Gonzales, Guadalupe, and Bexar counties, reported that hot, dry, windy conditions dried out crops and pastures. However, rangeland and pastures remained in fair to good condition. Corn and grain sorghum were stressed from lack of moisture but were still expected to finish. Hayfields needed a rain for a chance of a second cutting. Dryland grain sorghum was doing great in some areas. Most sunflowers were being harvested with good yields reported. Livestock remained in good condition, but horn flies were becoming an increasing problem.
AgriLife Extension district reporters for the South District, including Atascosa County, reported there was very little rain received, with only a few counties reporting light showers. Willacy County was the exception with 0.25 to 1 inch received. Highs of 100 degrees and above continued to be recorded throughout the region, causing soil moisture levels to decline. Soil moisture levels were mostly short to adequate throughout the region, except adequate levels in Atascosa, Dimmit, Maverick, and Cameron counties. Rangeland and pastures remained in fair shape, but forage quality deteriorated due to drought stress. Livestock producers continued providing supplemental feed to cattle. In Atascosa County, crops were doing well with some hay harvesting being done.
AgriLife Extension district reporters for the Coastal Bend District, including Karnes County, reported recent rains greened up some areas, but came too late for many crops. Soils were dry again. The grain sorghum harvest was under way with less than average yields reported. Many fields did not make a crop. The corn harvest began. Soybeans made a good pod set but needed rain soon. Grasshopper populations were high in some areas. Ponds were very low or dry in many areas. There were reports of cattle deaths due to toxic pond water conditions. Fish deaths due to low pond levels were also reported. Pecan yields were down from last year.
Robert Burns has nearly 30 years’ experience writing about agriculture and agricultural-related research. He writes about Texas AgriLife Research and Texas AgriLife Extension Service activities at the Overton Center and centers in Stephenville and Temple.