Taking the Risk Out of Cover Crops


Cover crops have long been touted for their ability to help maintain soil health, control erosion, reduce nutrient loss and improve soil fertility. But could they put grain and oilseed crops at risk by playing host to disease and pests?

That’s a question OMAFRA field pathologist Albert Tenuta is trying to answer. In this video, Real Agriculture visits with Tenuta at a Rodney, Ontario test site where he’s evaluating 26 different single-species cover crops ranging from sunn hemp to cereals, ryegrasses and brassicas.

“Cover cops are a wonderful tool,” says Tenuta, “but from a pathology perspective we’re always concerned about if there is potential to increase diseases. We don’t have a good handle on what these other cover crops, individually or as a mix, have as potential hosts for many of these diseases.”

Quite simply, it’s better to be safe than sorry, says Tenuta. “We don’t want a ‘Typhoid Mary’ situation where we’re doing all these wonderful things, and we’re benefiting from soil integrity, soil health and good stewardship management, but are inadvertently, maybe potentially increasing a disease risk,” notes Tenuta.

Cover crop research at the Rodney test site, sponsored by Grain Farmers of Ontario, is looking at the potential role cover crops could play as a host crop for soybean cyst nematode (SCN), which costs Ontario cash crop producers more than $10 million annually in lost yield. So far the news has been pretty good, says Tenuta. “We’ve run this for two years now and we have not seen any reproduction for soybean cyst nematode on those 26 cover crops.”

Tenuta has seen some increase in root lesion nematodes in sunn hemp at the site. In the US, sunn hemp is promoted for its ability to control root-knot nematode as well as SCN, “but in our trial we’ve seen an elevated number of root lesion nematodes so we’re looking at it as a potential trap crop or a host crop that could cause risk for producers.”

Tenuta will have a full report on the trial this winter.

Related: Trusting Cover Crops Pays Dividends

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