This article was written by Cameron Ogilvie, Soil Health Educator at the Soil Health Institute,
based in Morrisville, NC.
The following is a summary of a panel discussion hosted on July 20, 2023 by the Soil Health Institute and McCain Foods. Watch the full discussion at https://youtu.be/fmv5gySl77I
What are profitable strategies for integrating cover crops in potato cropping systems? This question was posed to a panel of growers and researchers across North America in a recent webinar hosted by the Soil Health Institute and McCain Foods.
The experiences of the panelists were as wide ranging as the geographies they represented, but they shared four themes in common. If you want to be profitable with cover crops in potatoes:
- Know your goal.
- Don’t expect perfection.
- Treat it like an investment.
- Reach out to experts.
Know your goal
Beyond the name, cover crops do a lot more than just cover the soil surface. They can regenerate soil health, catch leachable nutrients, and provide forage for livestock, to name a few examples. Having a clear idea of what you’re trying to achieve is the first step to managing cover crops profitably.
“What I’m trying to accomplish is to increase and stimulate the soil biology to a point where [the ecosystem] is conducive for healthy and resilient potatoes,” says Ladd Wahlen, co-owner of Roots Potato Chips in Idaho.
Wahlen has been using companion crops and pollinator habitat on his potato acres for some time. Starting out with pollinator islands and now using a 3-row pollinator strip, Wahlen grows a 17-species mix to attract beneficial insects to prey on pests. “To this point we haven’t had to apply an insecticide on this, so we’re seeing good things from these pollinator strips so far.”
But your goals may change over time, which is why Dr. Mike Copas, Senior Agronomist at Wysaki Farms in central Wisconsin, encourages growers to be flexible. In the beginning, the farm used cover crops to control erosion on their sandy soils. Recently, their goal has shifted to using cover crops to protect groundwater.
Describing his thought process, Copas explains, “Maybe disease control isn’t the thing that I need to focus on. Maybe I’m better served looking at nutrient management, soil health, soil tilth, some of these other things. I’ll get to disease management eventually. But that may not be the least common denominator that I’m chasing today.”
Don’t expect perfection
With anything new, there’s a learning curve. “I always tell our growers: Start small,” says Dr. Manphool Fageria, farm manager at McCain’s Farm of the Future in Florenceville, New Brunswick.
For cover crops to be profitable in potato systems, the agronomy – species selection, planting, termination method and timing – has to be dialed in. Fageria has learned this over time: first with simple, single-species covers, and then with mixes.
“I started with 8, 9, 10 species, then when I go back into the field I realized, I shouldn’t have planted those 3-4 species based on plant stand performance.”
“You may not get this tabletop field of a cover crop. It may look ugly! But that’s okay because it’s in a better position than where you normally have had it.”
In addition to starting off small, Copas advises growers to manage their expectations. “What you have to accept is something that isn’t picture-perfect or aesthetically pleasing.”
Getting comfortable with good-enough can save a lot of unnecessary passes across the field. “The more passes we do, we lose some of the benefits,” warns Dr. Mohammad Khakbazan, Research Scientist with Agriculture and Agrifood Canada in Manitoba. For cover crops to be profitable, they need to streamline your operation, not add loads of extra work.
In addition to the labour and fuel costs, more passes – whether tillage or chemicals – disturbs the soil. Each pass undoes some of the benefits that the cover crop provides by releasing carbon, breaking down structure, and impacting soil microbes.
At Wysaki and McCain’s farm of the future, they try to do as much as they can in one pass.
“Every single pass costs $20-25 per acre,” explains Fageria. “When we prepare our ground and plant cover crops in the fall, we put the air seeder on the back of the hiller, so that in one pass we make the hills and plant the cover crops.”
Treat it like an investment
It can take time to see the economic benefits of cover crops, which is why Khakbazan recommends looking at cover crops as an investment.
“As part of any business you do investment. You may not see a benefit right away, but you will see a benefit long-term.” In this way, cover crops are an important part of doing maintenance on the soil and building resilience into the enterprise.
But there are ways to reap a quick return. “Soil erosion or weed suppression are the instant effect,” says Dr. Bee Chim, Assistant Professor at the University of Maine.
Chim has been researching planting dates for cover crops in Maine. While it’s preferable to get cover crops in before September 15, Chim has demonstrated that planting as late as mid-October is still possible for the region and is beneficial for reducing erosion.
“If we start treating soil erosion as money-losing, I guess everyone would think ‘profitable’ in a different way.”
The fertility credit from cover crops is another way to see a faster return on investment – if it’s counted.
“Nitrogen is a big part of greenhouse gas emissions,” notes Khakbazan. When a nitrogen credit isn’t accounted for, it keeps unnecessary expenses on the ledger and increases the likelihood of nutrient losses via groundwater leaching and greenhouse gas emissions.
Fageria and his team at Farm of the Future have made sizeable reductions in fertilizer use because of cover crops. “We have cut 15% nitrogen, 40% phosphorus, and over 15% potassium as compared to a typical grower in our area.”
Wysaki has a similar story in Wisconsin. “We’ve seen up to 10-tonne yielding sweet corn with no nitrogen applied,” says Copas, “so we know there’s a huge benefit if we can have these companion crops with it.”
Reach out to experts
The final theme the panelists shared was the value of finding people who are doing what you want to do.
“A smart man learns from his own mistakes; a wise man learns from others’ mistakes,” says Wahlen. “Find someone who is doing what you’re doing, and model after them.”
Fageria and Copas agreed and added that this can be particularly important when sourcing good seed for cover crops. Knowing someone who has been successful can lead you to trusted seed dealers and save a lot of headaches down the line by avoiding bringing in noxious weeds.
There’s also the social support aspect. It’s hard to stick with something new on your own. Having a support network can help you process challenges and find solutions.
“I think it’s important in this whole regenerative and sustainable framework to just try things that are a little different,” says Wahlen. “Don’t go too fast but try things that are just a little different.”
Note: The video below can also be watched on YouTube here