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Reducing inputs through intercropping

In Part 2 of a 2-part series, a panel of farmers discuss the benefits of intercropping

Many producers who adopt intercrops and cover crops are looking to increase soil and plant health and reduce the need for inputs such as synthetic fertilizers. That effect often becomes clearer the longer they manage the system.

The three producers on a panel at an Intercropping Workshop in Brandon, Man., last November shared how they have reduced inputs through intercropping and other regenerative practices on their farms.

Joe Wecker farms at Sedley, Sask., 35 minutes southeast of Regina, growing both organic and conventional crops. His fertility program is fairly complex and begins with some extensive soil testing. Not only does he do a normal soil test that shows the soluble nutrients in his soil, he also tests plant tissue throughout the year to see what actually ends up in his plants. For Wecker, it’s vitally important to have a total test of all the nutrients in his soil. “How do I know if I have enough molybdenum, silica, selenium or cobalt so my soil can run on all eight cylinders?” says Wecker. “I don’t know until I do the test.”

Wecker’s next step is to increase his soil biology to make those nutrients available. For his in-furrow program (and also the foliar program on his organic crops) he uses one litre of humic acid, one litre of molasses and four litres of boron per acre. “We are always low on boron, that’s why it’s in there,” said Wecker. “I’m always putting on fish, kelp and folic acid, it’s a plant growth promoter which just makes the plants much healthier, and then I have the nutrients that I need on the conventional side or organic side that are lacking.”

Nick Cowan, who has a mixed grain and been operation near Hartney, Man., is putting no fertilizer at all on his intercrops. “This spring we did Roundup, sowed the peas and canola and didn’t put a drop of fertilizer on and it worked out really well,” he said. “We just sprayed a half rate of Pursuit and a grass killer.”

He’s trying to use cover crops to build up nitrogen so he can cut back on subsequent crops. “It depends on the crop. With wheat, corn or sunflowers, we’ll cut back on nitrogen after a cover crop and we don’t see any yield deficit,” he says.

But it’s not the same for canola. This year Cowan did trails with 80, 100, 120, and 140 pounds per acre of nitrogen on canola after a cover crop and saw a yield response with the nitrogen which he says was disappointing. “It was right after a multi-species cover crop with legumes so I thought that we wouldn’t see that much difference. The more nitrogen we put on, the more canola we grew,” he said. “I think different crops need fertilizer differently, obviously. But the response on the intercrops is cutting fertility in others.”

Patty and Andrew Harris are transitioning their grain farm near Stonewall, Man., to organic production. They are new to intercropping this year, but they have been trying cover crops before and after cash crops to increase soil fertility.

The Harrises have a three-year rotation for their organic fields. The first year is a green manure, then two years of cash crops. “In our green manure, we were trying to do a large variety of crops,” says Andrew, “Our first goal is to have something growing as much as possible. We also are trying to graze our green manures and add to soil biology. We strategically spread our manure on fields that need it the most.”

The second goal is to get two plough-down crops in the growing season. “We are trying to put our cool-season green manure crops in fall or early spring and work those down,” he says. “We seed our warm season plough-down crops after our cool seasons. We want to produce as much nitrogen in our green manure year as possible, which isn’t possible with our legumes. On our first year off of green manure, we have tried one intercrop and that is wheat and flax.”

They chose this mix because they wanted more nitrogen to produce protein for the wheat. “Our other intercrops have been on the second year off. That way we can supplement the nitrogen needed for the companion crop using a legume,” says Andrew.

Weed, pest and disease control

Intercropping proponent Joe Wecker says increasing soil biology has allowed him to approach disease control differently, and he hasn’t used a fungicide in years. Increasing soil biology has also allowed Wecker to approach disease control differently, and he hasn’t used a fungicide in five years. “We realized that a crop is never deficient in a fungicide, it’s actually deficient in nutrients or lack of biology,” he said. “It was a turning point for us because I think fungicide is actually the harshest chemical we use on soil life and biology and it was nice to see us get away from those and have an alternative and that’s a nutrient application. That’s how we started to turn on and off diseases in barley, for example. One pass of boron cured net blotch.”

On crops like chickpeas and durum or Khorasan wheat, where he can have issues with fusarium or other diseases, he actually applies a fungus which colonizes the plant so there’s no room for other fungi to grow in the plant. “It works better than any synthetic chemical,” he said.

He also grew a three-way intercrop this year — peas, lentils and camelina beside each other on 1,000 acres to spread the risk of root rot issues in his pea crop. “I seeded lentil because I knew I had root rot issues in my peas every year, so I added the lentils in case the pea didn’t do good, so I would still have lentil grain,” says Wecker. It turned out to be a good strategy because his pea yield was low but he had another five bushels per acre of organic lentils at $1/lb. as insurance.

Cover crops have been huge for weed control on Cowan’s farm. “Every crop is different, but we don’t spray any grassy herbicides on our cereals,” he says. “I think it’s probably the cover crop competition. We usually spray a cheap generic broadleaf in our wheat and annual rye grass and perennial ryegrass. Our spring annuals we don’t spray a grass herbicide. Same with on broadleafs, we’re cutting back. We basically just spray a grass killer on our sunflowers. With intercropping, definitely you see cleaner fields on the weed side and cover crops is definitely way less weeds and weed suppression.”

Cowan only sprays insecticides in an emergency and has also quit using fungicides because he simply doesn’t need them. “If we see a problem we’ll tweak our rotation the next year and try and fix it that way, or tweak our cover crops,” he says.

Andrew Harris does still use some tillage before seeding and harrowing in-crop but is using intercrops to get more crop biomass to choke out weeds.

He’s had dry years since moving to organic production so hasn’t had much disease, but he’s hoping the intercrops will also help with reducing disease issues in the future.

The farm does have flea beetles some years, but they have noticed a lot more beneficial insects, birds and butterflies that he’s hoping will provide biological control for pests. “This year, we grew alsike clover and we were told that we need to get honey bees out there to pollinate it. Every time I walked out there would be five or six wild leafcutter bees every square foot and we had great yields on the alsike clover without having honeybees on the field,” he said.

Separating intercrops

A big question with intercropping is how to separate the crops. Wecker has his own seed cleaning plant but admits that it can still cause a few grey hairs and it’s not easy especially with larger volumes.

“I ran into a problem this year, I couldn’t get the flax and chickpeas separated because my screening part of the cleaner was too small, it couldn’t take the flax away so I had to add more equipment in front of the line to do the separating,” he says.

Separation actually starts before you seed, he added “You have to make sure you can separate it. That’s why for our peas/lentil/camelina intercrop we used large size peas, small beluga lentils, and the Camelina is even smaller so it’s easy to separate. It makes life a lot easier.”

Wecker isn’t usually separating the seed right off the combine, but storing it and separating later, often when he’s ready to sell it. In some cases — especially with chickpeas in the mix — that can be a benefit. Chickpeas will form a crust at the top of the bin after being in storage for several months, but flax in the bin with them prevents it.

Harris uses a rotary screener to separate his intercrops but admits it’s not the most efficient way to do it. He advises starting with a canola/pea intercrop which is easier to separate with a screener. “When you get into a cereal and a pea, it’s hard to get every little bit of pea out with a screener,” he says.

There might also be some alternatives to separating intercrops on-farm. Harris is looking for end markets that will purchase intercrops to use as is, like for instance a barley/pea intercrop to an organic dairy. One of Wecker’s customers who needed peas early took his pea and yellow mustard intercrop, separated it and gave him back the mustard screenings.

What to grow

Joe Wecker says he doesn’t really have a plan for his rotations year to year. “The plan is made when our combining is over, it’s whatever we feel should be next year,” he says. He only plans to grow peas on the same land every three to four years.

“We don’t really have a plan, necessarily, because we’re running so much every year that by the time we get to the next year, we want to plant something different and try different things and learn,” says Cowan. “But with an intercrop we try to put as many mixes in as possible. This year, we did up to 15-way mix and we liked it because something always grew. The first year is always in an intercrop, second year we like to do a wheat for protein on pea or corn. Next year our goal is to put intercrops in our corn and this year we did peas and flax and really liked it. We’ll probably do that again, so that our first year would be an intercrop and then in our second year, when we get a little more weed pressure, we’ll put an intercrop in to jump on weeds. Our goal this year is almost to have intercrops throughout the whole farm.”

Andrew Harris believes that to have cover crops, he needs to know what he’ll be growing for the next couple of years but it also has to be flexible. “You either need to have a plan and go the next couple of years knowing what you’re going to sow or be able to change on the go,” he says.

About the author

Contributor

Angela Lovell is a freelance writer based in Manitou, Manitoba. Visit her website at http://alovell.ca or follow her on Twitter @angelalovell10.

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