Banding together: how targeted herbicide application and cover crops are reducing weeds in soybean crops

Like many crops, soybean in the Maritimes is battling a costly enemy: weeds. With weeds affecting the region’s soybean farmers to the tune of an estimated $14 million each year in lost yield, finding sustainable solutions has become more important than ever. Dr. Andrew McKenzie-Gopsill, a research scientist with Agriculture and Agri-Food Canada (AAFC) at the Charlottetown Research and Development Centre, has been working alongside the Atlantic Grains Council to explore innovative ways to reduce herbicide use while improving weed control. This research is paving the way for more sustainable and cost-effective soybean production in the Maritimes.

For three growing seasons, Dr. McKenzie-Gopsill and his team tested the use of cover crops, including fall rye and tillage radish, planted between soybean rows and paired with a reduced herbicide approach called herbicide banding. Herbicide banding involves applying herbicide in narrow strips directly over the soybean rows, instead of over the entire field, drastically reducing the amount of herbicide used.

“We showed that by combining cover crops with this targeted herbicide technique, soybean farmers could reduce herbicide use by up to 73%,” says Dr. McKenzie-Gopsill. “This not only helps protect the environment but also saves money for producers, which is critical for their long-term success.”

Herbicide banding and cover crops in harmony

Dr. McKenzie-Gopsill’s research tested several combinations of herbicide banding programs with and without cover crops. These included preemergence herbicide-only (applied before plants emerge from the soil), postemergence herbicide-only (applied after plants emerge from the soil), a combination of both preemergence and postemergence herbicides, and a no-herbicide control.

Cover crops were planted between soybean rows, which were widened to 30 inches in some fields, instead of the conventional 6 inches, to allow for herbicide savings. Dr. McKenzie-Gopsill found that tillage radish and a mix of fall rye and tillage radish provided the best weed suppression between rows, rivaling the performance of broadcast herbicide sprays.

“Some cover crops act as natural bodyguards against weeds,” explains McKenzie-Gopsill. “They compete for resources like water, nutrients, and light, making it harder for unwanted weeds to grow.”

More than just weed control

Read more