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Climate-smart cropping systems for the Prairies

Diversified rotations, including pulse crops, achieve overall positive results.

June 7, 2024  By Donna Fleury


Fully phased cropping study under a four-year rotation at Beaverlodge, Alta. Images courtesy of Greg Semach, AAFC and Lee Poppy, AAFC

Well-designed cropping systems can achieve multiple goals simultaneously, helping growers optimize crop productivity at the same time as improving whole-farm sustainability and resiliency. Understanding the complex interactions between crops and the trade-offs and synergies among different cropping systems will be key to helping growers identify productive, sustainable and resilient cropping systems and adapt to climate change.

“We have a multi-disciplinary team of researchers across the Prairies involved in a project comparing different cropping systems for agronomics, productivity, economics and their capacity for sustainability and resiliency,” says Kui Liu, research scientist and project lead with Agriculture and Agri-Food Canada, in Swift Current, Sask. “The goal is to provide a good strategy for maximizing overall cropping system performance, sustainability and resilience at the same time minimizing negative environmental impacts in major Canadian ecozones. Using multiple indicators and criteria to assess the complicated interactions between crops and the trade-offs and synergies among different systems indicators will help to identify the more productive, sustainable and resilient cropping systems for each of the ecozones.”

The study includes six carefully designed cropping systems that are being evaluated at seven ecosites across Alberta, Saskatchewan and Manitoba using a four-year crop rotation cycle repeated over the project. Cropping systems include conventional, intensified, diversified, market driven, high risk-high reward and a soil health-focused system. Researchers will be collecting and assessing a lot of data throughout the project that will help to understand the tradeoffs and synergies among the different system indicators. Through the project, multiple indicators such as crop yield, soil health, pest levels, economic returns, carbon footprints and nitrogen-use efficiency are being used to assess cropping systems.

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The first phase of the project was initiated in 2018, and the 2023 cropping season is currently in year two of the four-year crop rotation cycle. Researchers have submitted funding applications for an additional five years.

Liu explains that using a systems approach in this project will help to better understand the complex intensively managed agro-ecosystems on the Prairies, which are very complicated, dynamic and change a lot over the years.

“Specific cropping systems and rotations interact with the surrounding environments, soil, climate and weather, which together all affect the cropping system performance,” says Liu. “Using a systems approach also helps to understand biotic and abiotic interactions in a cropping system at the same time identify key drivers affecting the cropping system. In order to evaluate true cropping systems effects, a longer term study over several years is necessary in order to make recommendations for the best cropping systems. In crop rotation studies, researchers normally count the first four to five years as a transition period because results may be confounded by previous cropping systems.”

Diversified rotation study plots at Swift Current, Sask.
Images courtesy of Greg Semach, AAFC and Lee Poppy, AAFC

Diverse cropping systems delivered better results
Although it is too early to be able to share any final outcomes of the project, there are two preliminary findings that stand out. Diverse cropping systems including three or more crops and pulses in a four-year rotation generally have better overall results. When rotations are diversified with pulse crops, there are obvious benefits even in a short period of time. The other main preliminary finding is that precipitation is the most important factor affecting the performance of cropping systems. Since precipitation is so different among sites, there is no single cropping system that fits all regions. Therefore, producers will need to develop site-specific cropping systems by selecting crops that best suit their local conditions.

“Including pulses does bring benefits to cropping systems,” adds Liu. “Along with cropping system diversity benefits, including pulses also reduces requirements for nitrogen (N) inputs. In addition, pulse stubbles could result in producing higher yields for the following crops. Our early findings show the diversified rotation had a much higher nitrogen use efficiency (NUE), although not always the highest yields. However, considering the current pressure to mitigate climate change or reduce environmental impact and reduce N inputs, the diversified rotation including pulses fits that goal very well. The diversified rotation produced decent economic returns but with much less N fertilizer inputs, making it a good alternative.

“The market-driven system in a short period of time did produce the highest economic returns, because there is a high frequency of canola in rotation. However, there were disease problems beginning to show up in these rotations, which will get worse if the frequency continues into the second four-year-rotation cycle. It is also important to realize that the high economic returns for a market driven system come with high N inputs. The N-driven economic returns have a low NUE and also a higher carbon footprint. The tradeoff is higher yield and return but lower NUE and a more negative environmental impact.”

For growers, setting clear goals when they plan rotations is key, whether that is to improve yields, yield stability or soil health, to control pests, increase NUE or gain economic returns. Liu explains that different crops have different functions and at the end of the day, growers need to strike a balance between all parameters. It is important when planning rotations to keep maximizing economic system services in mind. Try to use nature to provide free services and maximize those services. A key strategy for long-term sustainability is to incorporate ecological principles/functions into cropping systems. Being innovative and using diverse rotations can achieve multiple goals. One strategy can be to try alternative crops or practices on a small scale to see if it works, and then scale up. Liu emphasizes that growers know their land better than anyone else and can balance their goals and optimize different cropping systems over time.

“One of our project goals is to transfer the knowledge and findings we generate through the research to growers and industry,” explains Liu. “With the cropping systems approach and using multiple indicators, we have developed multiple factsheets that provide valuable insights and information on different system indicators. This allows growers to selectively choose the information that aligns with their goals, whether that is maximizing yield, stability, NUE or economics. The information can help them assess the rotations and indicators to optimize their cropping system.

“As the project progresses into additional rotation cycles, collecting much more data over more years and environmental conditions will make the rotation information much more valuable. We will also be developing a sustainability index, which will incorporate all of the different indicators into a single indicator. Our plan for the next phase of the project is to expand the soil health component to include soil carbon sequestration and greenhouse gas measures, assess resilience of cropping systems, use a model to predict cropping system performance and develop a sustainability index. These additional measures aim to provide a more comprehensive understanding of the performance of cropping systems and to help balance long term sustainability and economic returns.”

This project is funded through the AgriScience Program as part of the Canadian Agricultural Partnership, a federal, provincial, territorial initiative. Other funders include: Agriculture and Agri-Food Canada, Integrated Crop Agronomy Cluster, Western Grains Research Foundation, Alberta Wheat Commission, Alberta Pulse Growers, Saskatchewan Wheat Development Commission, SaskCanola and Manitoba Crop Alliance. 

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