b'COVER CROP CORNERWHERE DO BRASSICAS FIT IN COVER CROPPING?WHEN COVER CROPPINGfirst started getting a hold in Western Canada it was triggered by tillage radish. In the United States it was being used with great success between corn and soybean, or after a winter wheat crop harvest to help loosen up the soil, activate soil calcium for the next crops, tie up nutrients to reduce the amount lost from the field to be released to the next years By Kevin Elmy crop, and help suppress weeds. Similar results Elmy is founder of Coverwere seen in Western Canada, but there were Crops Canada. His bookssome failures.Cover Cropping in WesternIn the United States most of the rotations are Canada and Not Justdominated by corn and soybean, namely a grass Dirt are available through Friesen Press, Amazon,and legume. In Western Canada, canola con-and digitally throughtributes a significant amount of some producersLike the rest of cover cropping, do not just use a Brassica Apple Books, Kindle, androtation. Radish is part of the Brassica family, theas a cover crop alone.Google Play. For more infosame as canola. This means they will share many on Cover Crops Canadaof the same pests, including insects and diseases.The best place for a Brassica in a cover crop is at visit covercrops.caThere are numerous times radish seedlings did notleast one year away from a Brassica cash crop, such survive. Or, we ran out of time for fall growth andas mustard and canola. In a rotation including a they were killed before they could improve thecereal, pulse and canola, look at using a turnip or soil. So where do Brassicas fit in cover cropping inradish in between the cereal and pulse. Ideally, it Western Canada? would be seeded after the pulse before the cereal. One of the keys for improving soil health isThis way the pulses that are normally harvested to increase plant diversity that has been grown inearlier in the fall will have some residue rot, releas-rotation or in the cover crop blend. The main fiveing nutrients. The Brassica can then absorb the functional plant group families are grasses, leg- nutrients, hold them until the next spring, then umes, Brassicas, non-Brassica broadleaf and forbs.release the nutrients as the Brassica cover crop rots.Brassicas are one part of the functional plant fami- Like the rest of cover cropping, do not just use lies. Other species in the Brassica group are turnip,a Brassica as a cover crop alone. Include a cereal, radish, kale, collards, forage rape, mustard, as wellbroadleaf, and forb plants in the mix. This will as weeds like wild mustard.further reduce potential problems, increases plant If canola or mustard are part of the rotation,diversity, and allows the soil aggregation to con-especially if in a tight rotation with canola it willtinue if the plants are alive.be difficult to find a spot to use other BrassicasOverusing Brassicas in cover crops can cause in a cover crop. Even if there is a lot of Brassicasother issues. Without balancing the calcium with in the area, there may be challenges establishingsome magnesium, the soils can become very loose seedlings due to high flea beetle pressure. and can be prone to erosion. We need to have Adding another Brassica into a rotation alreadymagnesium on our base saturation around 15 to with a Brassica does not add any diversity and20%. Another issue of Brassicas is the high nitro-will create new issues. The idea is to get a plantgen content of the residues. Like the rumen, there with similar function of increasing plant-availableneeds to be balance of carbon to nitrogen for it to calcium in the soil from a different functionalwork properly. plant group, like beets. Beets will produce a largeBrassica residue when breaking down will tuber that when it rots will increase calcium levelsrelease a lot of nitrogen into the soil. For the in our soils.microbes to utilize this burst of nitrogen, they Increasing our calcium is important evenneed a good carbon source, like root exudates. If though a soil test will show we have a lot in mostthere is not enough liquid carbon being injected soils. We need it in a more plant and micro- into the soil, the microbes will then use the next bial friendly form, that is, calcium with carbonsource of carbonour soil organic matterand attached to it. this will start the decline of soil organic matter.30 SEEDWORLD.COM/CANADA JANUARY 2025'