Ontario Grain Farmer March 2021

great nitrogen scavengers and some of them winter kill. She adds that buckwheat is a cover crop option that has received mixed reviews in Ontario. It is a fast-growing smother crop that supports pollinators and has a fragile root system that builds soil structure. The caution is that buckwheat can flower within four weeks and can have seed set within six weeks. STEP 3: PLAN ESTABLISHMENT In terms of cover crop establishment, Verhallen understands that it is easier for most farmers to broadcast seed but wants to draw attention to the benefits of drilling. Stefan Zehetner, owner-operator at Huron Cover Crops, has many customers who broadcast and incorporate their cover crops in the summer and early fall with good results. But he has noticed that when farmers broadcast seed on top of the field, they end up with smaller root systems than if the seed had been planted at the proper depth. On his own ground, Zehetner prefers to drill cover crops. “I feel that the set up coming into spring — especially if you’re going to plant green — is to keep everything even and have an even stand which allows your planting pass to go more smoothly,” he says. Follings agrees that drilling is themost effective and cautions that while there may be advantages to aerial and broadcast seeding, there are also related challenges. These methods present challenges of slugs, heaving, and wind and it can also be difficult to achieve uniform application. “We tend to see issues with seed-to-soil contact and stand variability so if you’re going to go the aerial or broadcast seeding route, you want to increase seeding rates by 10 per cent,” she says. STEP 4: PLAN TERMINATION “Whether the cover crop is going to freeze over winter, you are going to spray it, or you are going to till it under, you should always have a termination plan before you even get the seed in the ground,” says Verhallen. Until more research is complete and agronomists can provide formal recommendations, she 8 advises that farmers should terminate the way that works best for them and seek advice from neighbouring farmers with the same soil type. University of Guelph research associate Kris MacNaughton is often asked for the best way to kill cover crops. “You would think that it is a straightforward answer but it really is not,” she says. “Depending on what your agronomic crop is, make sure your herbicide is not going to cause rotational issues later on. Glyphosate kills a lot of the cover crops we are using right now but you have to make sure you are timing it right and using the right rate.” For example, McNaughton says growers can likely use a low rate of glyphosate and spray winter rye at 0.67 L/acre and be happy with the termination. But for annual ryegrass, farmers need to use at least 1.34 L/acre and mix with a Group 1 herbicide. To terminate clovers, farmers can use a high rate of glyphosate coupled with a Group 4 herbicide and should follow the label instructions." In addition to the four steps of planning, Verhallen recommends that farmers who are new to cover crops should start small, plant in a visible location, and use a winter killed species such as oats, radish, or a simple mix. “It is a good idea to target early harvested crops like wheat and small grains, vegetables, or silage corn. These are the crops that have the biggest window after them for us to get the most growth and potential benefit from the cover crop,” she says. Read about long-term cover crop research trials in the April/May issue of the Ontario Grain Farmer. l LONG TERM COVER CROP EXPERIMENT. PHOTO COURESTY OF DR. LAURA VAN EERD. continued from page 6 This article is based on information provided during a session of the Ontario Agricultural Conference. Grain Farmers of Ontario was a sponsor of this conference.