ROTATION RETHINK
BY GEOFF GEDDES • PHOTO COURTESY OF DEVIN SERFAS
Variety is the spice of life, and a shakeup in crop rotation may add bite to the farm bottom line. This is the premise of recent research on crop rotation and its impact on profits and the environment. Through analysis of 20 years of Saskatchewan farmland insurance data on rotational choices in correlation with soil organic carbon (SOC) levels, researchers Devin Serfas and Richard Gray found clear benefits in certain rotations.
“We wanted to assess the long-term effects of crop rotation on yield,” said Serfas, an assistant professor and Results Driven Agriculture Research chair in applied agricultural economics and risk management at the University of Alberta. Gray is the Canadian grain research chair at the University of Saskatchewan and led the project on behalf of the Saskatchewan Wheat Development Commission. “We knew certain rotations increase SOC, which is a key factor in soil health,” said Serfas. “In field trials, more SOC meant greater yields, but is it the same on-farm?”
As an economist, Serfas wondered how various rotations would impact profitability. He was also intrigued by the effect of specific rotations on carbon sequestration. Seeking answers, he spoke with soil scientists and examined their digital modelling that illustrates the efficiency of carbon sequestration in various rotations.
A BLACK AND BROWN ISSUE
“In areas with a lot of precipitation, the most effective rotation for increasing yield was canola-spring wheat-canola-spring wheat,” said Serfas. “For brown soil zones, however, canola-spring wheat-pea-spring wheat was the best option. Since canola requires considerable moisture to thrive, you should limit its involvement in those drier brown zones.”
As well, increases in SOC had a greater impact on yield in brown zones, where soil carbon levels are typically lower than in dark gray or black zones. From a crop standpoint, wheat and durum saw a better yield benefit from higher SOC than other crops.
“Our main takeaway was that, in deciding on their crop rotation, farmers should consider not only commodity prices, but also how that rotation will affect carbon sequestration and its long-term impact. You might not see benefits in the first few years, as they build up over decades.”
Though Prairie farmers aren’t inclined to boast, through their adoption of new field practices in recent decades, they have already made huge gains in this area. “Over the last 20 years, farmers have done an excellent job of increasing carbon sequestration, and they don’t get full credit for that,” said Serfas. “Their efforts are worth billions of dollars to society in reducing flooding, volatile weather events like hurricanes and tornadoes and other aspects of global warming.”
Pointing to a study conducted at the University of California, Berkeley, Serfas noted, “each [short] ton of carbon dioxide emitted into the atmosphere costs society US$185 per ton. That differs from the number the Trump administration cites, which is $0,” said Serfas.
SPARE SOME CHANGE?
While an adjustment in crop rotation may have merit on paper, real-world adoption is a tall ask. Statistics Canada identified a substantial shift in crop selection by Alberta farmers in the spring of 2025, largely due to low moisture considerations. For the most part, though, farmers are reluctant to change their rotation. Serfas’s research may provide broader incentives.
“Diversity can be a great way to reduce your risk,” said Maryse Bourgault, assistant professor at the University of Saskatchewan. She was not involved in the study.
Where a farmer seeds canola and wheat year after year, with the odd pulse crop thrown in, adjustment to the mix may address inevitable agronomic side effects. “Growing the same crops every year can lead to greater disease pressure,” said Bourgault. “By altering your rotation, you may interrupt the lifecycle of diseases and minimize their impact.”
Variety in cropping may also limit economic risk as global tariffs become more commonplace. Of course, the decision to change your rotation is step one; you then need to make practical crop choices. “Speaking from my own experience as a researcher, I work a lot with legume,” said Bourgault. “Because they fix nitrogen, they don’t require added fertilizer, so people save on input costs. This will also benefit a following crop of canola, flax or wheat in terms of available nitrogen.” Bourgault stressed that willingness to vary a rotation helps a farmer adapt to changing conditions such as wetter years that often spark an increase in fungal disease.
WILLINGNESS AND PERSISTENCE
While such benefits may entice a farmer to vary their rotation, a little added incentive may also help. “Funding for an agronomist to aid growers could make a difference,” said Bourgault. “Some farmers tell me that they tried to change rotation and it was a disaster, so they won’t do it again, but nothing works perfectly the first time. You need to learn from experience, and a professional mentor can help guide them on new crops and methods.”
Greater development of markets for niche crops by government may also assist. “There are crops like mustard and camelina that grow well on the Prairies, yet we don’t see a lot of acreage for them,” said Bourgault. “With pea, you need six to eight years between crops to manage Aphanomyces [root rot], so if we had better prospects for exporting chickpea or fava bean it would help with economic risk while enhancing soil health.”
Often, to make a change may require reassurance from another key source: your neighbour. “Producers need to see tangible benefits to adopt a different rotation,” said Kui Liu, research scientist with the Agriculture and Agri-Food Canada Swift Current Research and Development Centre. Liu was also not involved in the research project. “If the farmer down the road has a new rotation and is seeing benefits, that’s great motivation to change.”
It’s also important that the new strategy is practical, simple to adopt and fits with existing farming practices. “Growers know that they may face short-term losses, but if they can see a clear path to economic or soil gains in the long run, they might give it a try,” said Liu.
As with much of farming, risk tolerance has a role to play in the decision to change course. “Grain prices definitely matter, though if a grower has farm-saved seed in the bin ready to use and it’s not costing him anything, why would he switch crops at that point?” said Serfas.
Certain farmers may be more inclined to roll the dice in search of the next big thing, he speculated. Generally, however, most won’t take a huge risk and seed a lot of acres to that specialty crop on the first try.
THE ROI ON SOC
An increase in SOC levels can produce substantial gains: greater nutrient cycling, better soil moisture storage for subsequent crops and greater capture of micro-organisms that offer a host of soil benefits. “SOC improves soil structure, holds water and nutrients tightly and makes crops more resilient to stressors,” said Liu. It often acts as a buffer that protects crops under harsh conditions. “This may not always increase yield, but it can reduce morbidity in your crops when they’re under stress.”
Liu suggested farmers be mindful of the big picture. “I would advise growers to take a systemic approach and not just look at a single indicator. Think about short-term gains and long-term crop morbidity.”
The results of Serfas’s study are not meant to be prescriptive. While his research outlines the potential upside to the adjustment of crop rotation, he recognizes each farm is unique. “The prospect of SOC-enhancing rotations seems to be a win-win for producers,” said Serfas. “Apart from improving yield and profits, it offers even greater benefits for the environment. That’s not to say you should do this, since outcomes vary considerably across fields and years, and depend on a farmer’s long-term plan.”
A change in rotation may have varying appeal among farmers, but improvement of soil health and an incremental boost to the bottom line are worthy goals that require long-term commitment. “Your actions now will greatly affect the future,” said Serfas. Tomorrow’s actions can also affect good work done in the past. “Should you decide to till the soil every other year, you could release a lot of carbon, and all of those hard-earned benefits over the last 30 years may be lost.”
Success with a specific crop rotation is not automatically guaranteed. Farmers are encouraged to conduct research, consult crop commission resources and consider the assistance of an agronomist. “Be patient and realize that every season is slightly different,” said Bourgault. “Sometimes you do everything right and it doesn’t quite work out, while other times it really pays off. Farming is a lifelong learning journey. Some people think it’s a recipe: do this and that and you’ll be fine. But as most growers know, it just doesn’t work like that.”
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