By choosing which crops to plant in their fields, Canadian prairie farmers may be able to boost their bottom line while also helping the environment.

Switching to certain crop rotations to increase the amount of organic carbon stored in soil could eventually result in higher profits while keeping harmful carbon dioxide emissions out of the atmosphere, new research from a University of Alberta expert suggests.

“It’s an opportunity to look down the road to some of the benefits of growing a crop that increases profits further out and improves soil carbon in the long run,” says agricultural economist Devin Serfas, an assistant professor in the Faculty of Agricultural, Life & Environmental Sciences.

Using Saskatchewan farmland as a model, Serfas, RDAR Chair in Applied Agricultural Economics and Risk Management at the U of A, investigated the long-term effects of planting different types of crops on soil organic carbon or SOC, and how that would affect crop yield and profitability, as well as environmental benefits associated with changes in SOC.

Derived from dead plant matter, SOC makes soil more fertile, but when released into the atmosphere through a crop practice called tilling — turning over the soil — it releases carbon dioxide into the atmosphere. 

Using Saskatchewan Crop Insurance Corporation data from insured fields over the past 20 years, combined with weather, plant and soil science models to predict SOC levels, Serfas estimated the on-farm “shadow value” of SOC. The calculation showed that in soils with lower SOC levels, like brown soil — which tends to be drier and less fertile than black soil — farmers have more opportunity to significantly improve their yields and profits by choosing crop rotations that boost SOC levels. 

Simulations were then run to estimate the SOC and yield response over time, using both common and conventional crop rotations, including tillage and leaving a field fallow for a year, which releases carbon into the atmosphere and leaves less SOC in the ground. 

However, long-term average profits for various soil types were much higher when an agronomically recommended, more optimal rotation was used, consisting of planting canola one year, followed in subsequent years by spring wheat, field peas, then spring wheat again, and repeating the same four-year cycle after that.

Long-term profitability, soil resiliency

The projections showed that if farmers adopt this specific rotation, they could see significant increases in their long-term average profits, of 27.5 per cent more than current levels in brown soil zones, 8.2 per cent more in dark brown soil areas and 4.4 per cent more in black and grey soils. The profit boosts are directly linked to the increased carbon being stored in the soil over about 32 years, or eight four-year cycles of farming, Serfas notes. 

The canola/spring wheat/field pea/spring wheat rotation also helps build biodiversity to keep crop diseases such as blackleg or clubroot in canola from concentrating in the soil, he adds. 

“It offers middle ground, carbon levels that are not too intense but also not too low.”

Beyond the farm, the environmental benefits are even greater — translating into potentially billions of dollars, the analysis showed.

Serfas calculated the wider societal value of switching to the recommended rotation, compared with a more traditional choice of growing spring wheat one year, followed by a fallow year, then repeating that pattern over four years.

Across all insurable cropland across Saskatchewan — representing about 80 per cent of the total — Serfas estimated environmental benefits of $108 billion from 2023 to 2055, when employing a social cost of carbon of US$185 per tonne of CO2.

“It’s a huge number, showing that based on what farms do, there are big consequences in terms of environmental benefits to be had by improving soil health and levels of soil organic carbon.”

Taking the long view

Although crop choices can benefit both the environment and their bottom line, it can also be a difficult decision for farmers when it takes 10 to 30 years to reap the rewards, Serfas notes.

“Farmers generally want to use good crop rotations, but they also want to pay their bills. The tough part of farming is wanting to mitigate risk to soil health by seeding a variety of crops, but when something like canola brings a high price, there’s a bit of an incentive to plant that year after year.”

The study “puts some numbers to how much money a farmer would get if they did switch to this rotation over a long time. It can be up to 27 per cent in areas with relatively lower SOC, which is a lot if you think about a farm that brings in a million dollars,” he adds.

The move to crop rotations that pay off in the longer run could also help preserve family farm legacies, Serfas suggests. 

“Intergenerational farms that want to keep the soil healthy and more productive for their grandkids will have more of an incentive.”

Though modelled on Saskatchewan farmland, the study findings could apply to other Canadian prairie crop producers in shared border areas with similar weather, crop yields and commodity prices, Serfas notes.

The research also points to the potential returns of investing in government programs that provide incentives for farmers to adopt more environmentally beneficial crop rotations, he believes. 

“We have some more insight into what the effects would be of investing in such programs; the societal benefits can be quite high.” 

The research was funded by the Saskatchewan Wheat Development Commission and the University of California Giannini Foundation of Agricultural Economics.