In recent years, crop production on the Canadian prairies is experiencing noticeable change as growers recognize the benefits of crop rotation and proper cropping sequence.  Crops grown in previous years may substantially affect yields of the current crops, by impacting occurrence and severity of stubble or soil-borne diseases, weed pressure, soil moisture, soil fertility and quality and other critical production factors.  To address the inquiries extended by the Prairie growers, a four-year project, aimed at identifying the best fit of novel crops into existing crop sequences, was executed at four locations (Lethbridge, Vegreville and Falker in Alberta and Indian Head in Saskatchewan) with contrasting agro-climatic zones, across the Western Prairies.  The specific goals included understanding the beneficial and negative impacts associated with the introduction of novel crops introduced on the performance of staple crops, and the mitigation of potential risks of crop failure resulting from inadequate management of these new crops stemming from a lack of novel crop production knowledge.

At each location, the trials included a core set of staple crops (wheat, barley, canola, pea) and selected novel crops that are gaining popularity in the given region. Specifically, durum wheat, hemp, quinoa, corn, and dry beans were tested under irrigation in Southern Alberta. In Central Alberta and the Peace Country hemp, quinoa, flax, and fababean were trialed, while corn, durum wheat, hemp, quinoa, soybeans, and annual canary grass were included in the Southern Saskatchewan experiments.

• Pulse crops including pea, dry bean, faba bean and soyabean were the best preceding cropping option enhancing field performance of both the staple and novel crops in the Western Prairies.

• Only fababean seemed to notably improve nutrient status (N, K, S) and organic matter of soils.
• Canola and quinoa appeared to be the worst preceding crops, consistently compromising the yields of the following staple and novel Prairie crops.
• Quinoa posed the most agronomic challenges such as severe weed infestation both in the year of cultivation and in the following year resulting from the lack of registered herbicides, late maturation and poor seed setting.
• Dry conditions aggravate negative impacts of canola, a non-mycorrhizal and high moisture using plant, on the performance of both staple and novel crops cultivated in the central and northern Prairies.
• Avoid seeding industrial hemp in sequence with canola. In particular under dry conditions, hemp seeded into canola stubble is prone to total crop failure.
• Further expansion of the high profit margin crops such as dry bean or hemp would warrant registration of new chemistries.

Above ground biomass yield was the attribute most affected by the preceding crops. The increased production of biomass was particularly apparent when the crops were seeded in sequence with the pulses. A relatively small number of negative impacts from monoculture were identified, and novel crops demonstrated less susceptibility to seeding in their own respective stubbles.

The highest number of volunteer crop plants was found in the plots previously seeded to easily shelling crops such as canola, flax and hemp, particularly when their harvest was delayed. Quinoa’s performance was especially prone to suffer from competition with the volunteers that could not be controlled due to the lack of the registered herbicides.