Crowding Out Weeds

Crowding Out Weeds

From Cotton Grower Magazine – February 2017



As soybean growers gear up for 2017, weed management will be foremost on their minds. Many places in the Mid-South are dealing with the dual-headache of glyphosate and PPO resistance for the second year in a row.

Luckily, Extension experts like University of Arkansas Extension Soybean Agronomist Dr. Jeremy Ross have devoted years of research to the topic of weed control. And while there are new herbicide options in the market, Ross says there are cultural management practices that could be equally effective in combatting weeds.

“We actually have three years of data that says if you can narrow up your row spacing to anything less than 30 inches – as opposed to 36- or 38-inch spacing that we typically see – then you can cut down on your weeds,” Ross says. “The reason we see less weed pressure and better yields is that with a narrow row, you get quicker canopy closure.”

Ross says narrowing up the rows can also increase irrigation efficiency. “Our research suggests that anything you can do to narrow up your row spacing, it seems like that enhances your yield.”

While there are new herbicide options available for the first time in 2017, the basics will remain the same for soybean producers, according to Ross. The best course of action is to start your herbicide program early.

“What we recommend is coming in with a really good burndown program,” he says. “Residuals are still working on the grasses and other broadleafs. We want our guys to start clean and stay clean. Once we get into the season, we want them coming in with overlapping residuals.”

Just like it has in cotton, resistant pigweed has become the dominant weed pest in soybean fields. It can be especially troublesome when dealing with both glyphosate and PPO resistance. That’s why Ross says he is recommending that his growers take a long look at soybean varieties that feature the Liberty herbicide trait.

“For guys in the PPO resistant and glyphosate resistant areas, Liberty is going to be the best option they have,” says Ross.