P.E.I. research zeroes in on new kind of cover crop to help break pest and disease cycles

A tropical grass seems like an unlikely fit for Prince Edward Island, but sorghum Sudan grass is growing in popularity when it comes to preventing disease build-up by rotating other crops through the fields where cash crops like potatoes are grown. 

New research from Agriculture and Agri-Food Canada shows planting the grass could also be of benefit to barley and soybean farmers. 

"It's more related to corn than a lot of the other grasses that we grow in P.E.I.," said Ryan Barrett, research and agronomy specialist with the P.E.I. Potato Board. "It tends to favour hot conditions, warmer conditions than other cool-season grasses like, say, rye grass or many other grains we grow.

"It has a deeper rooting structure than some of those other grasses as well. And we've also seen in the last number of years that it can have some benefits in terms of breaking disease and pest cycles."

Barrett said farmers on P.E.I. have been growing Sudan grass for at least 10 years, in small amounts to start. The board has included it in agronomy trials for the last seven to eight years. 

"Some growers were tinkering around with it. Maybe they'd seen it being grown somewhere else or they'd seen literature on it… And so they were trying it here," Barrett said.

He said the board gets involved by getting data from their fields and collaborating with Agriculture Canada on test plot experiments.

"And then we can kind of see on both sides, both plot scale and field scale, whether it's having the… intended effects."

Barrett said Sudan grass is usually planted in June, or even July, adding: "You have to kind of wait to plant it into really warm soil and then it'll take off really quickly."

The board surveys its member producers every year about their fall cover crop plans. Extrapolating from those results, Barrett estimates the Island has 10,000 to 12,000 acres of Sudan grass or the closely related pearl millet being grown as a cover crop, either alone or in combination with other crops.

"I just think it's another tool in the toolbox for some people… For some people's rotations, it seems to work really well," Barrett said.

"There's no real slam dunk for everybody. It may fit for some rotations and not for others."

On the federal side, Agriculture and Agri-Food Canada research scientist Adam Foster has also been exploring the potential of sorghum Sudan grass, as part of a larger project led by the Atlantic Grains Council, located at the Charlottetown Research and Development Centre.

"We were exploring a number of different cover crops to see what effects they would have on the soil microbiome and what carry-over effects that might have to disease on barley and soybeans," Foster said.