Diversifying with forage seed crops
In the Peace River region, studies have shown multiple benefits of integrating perennial forage seed crops into cropping systems. Along with improved yield, profitability and climate resiliency, diversified cropping systems also increased soil organic carbon, enhanced nutrient efficiency, reduced weed density and disease levels and improved economic performance.
Cropping systems in the Peace River region generally included rotations between annual grain and perennial forage crops best suited to the Grey Luvisol soils and climate of the region. At one time, the Peace region was considered to be one of the world’s largest producers of turf and forage seeds. In recent years, cropping systems have seen an expansion in annual crop acreage, while acreage of perennial forage seed crops has declined. These simplified low-diversity cropping systems have a heavy reliance on external inputs and have been prone to the rapid evolution of herbicide-resistant weeds, outbreaks of crop diseases and insect pests in the face of changing climate.
A research project reviewed several crop rotation and diversified cropping sequences studies conducted in the Prairies and Peace River region of western Canada to determine the economic benefits of integrating perennial forage seed crops into cropping systems.
Numerous studies have concluded that including forage legumes in cropping systems result in both nitrogen fertility and soil improvement effects in the Peace region. A recent study compared 4-year crop sequences of wheat, canola, barley and peas with and without the inclusion of perennial seed crops such as creeping red fescue, alsike clover and red clover, in rotation. The results showed that the creeping red fescue-based cropping sequences had higher canola equivalent yield and gross margins compared to the annual crop-based sequences. The same study showed that growing biennial legume seeds crops of red and alsike clovers prior to wheat followed by canola crops could replace nitrogen fertilizer requirements by at least 80 lbs/ac (90 kg/ha) for wheat and 40 lbs/ac (45 kg/ha) for canola.
Other studies showed that diversified crop rotations continue to be the most effective pest management tool, reducing disease risk, weed density and insect pests. Studies comparing continuous canola with canola grown after two break-crops showed 54% less incidence of blackleg disease, 6% less root maggot damage, lower incidence of brown girdling root rot and higher seed yield for diversified rotations.
Another study comparing continuous canola with a 4-year cropping sequence of wheat-pea-wheat-canola and wheat-flax-wheat-canola showed the diversified rotations had 2.6 times less blackleg incidence.
A recent meta-analysis of over 50 crop rotation studies across six continents showed a reduction of weed density by 49% in diversified crop rotations. Combining practices such as zero-tillage and seeding time manipulation with diversified crop rotations can increase the reduction in weed density by up to 65%.
Improved yield with diversified forage seed crops
Several other cropping systems studies with the inclusion of perennial forage crops show that diversified cropping systems and proper crop sequence can have significant yield advantages, including yield-enhancing effects to subsequent crops. The results from a recent study conducted at Beaverlodge showed that an unfertilized wheat crop preceded by a biennial stand of red clover or alsike clover had a 45% higher yield compared to a wheat crop preceded by two years of annual crops. Compared to annual crop sequences, a canola crop grown after a wheat crop preceded by clovers in sequence produced yields 40% to 70% higher.
Integrating perennial forage crops into cropping systems can also be done by underseeding clovers and grass seed crops with annual crops to compensate for the seasonal lag of no seed production in the year of perennial forage establishment. Perennial forage crops typically begin producing seeds in their second year and continue for multiple years from a single seeding. They also tend to mature earlier than annual crops, allowing for an earlier harvest. Integrating perennial forages with annual crops also provides opportunities to better utilize farm labour and equipment over the season without competing for the time for annual crop harvest.
Diversified rotations that include forage seed crops provide significant agroecological and economic benefits and enhance cropping systems performance in terms of productivity, resilience and resource use efficiency. Opportunities for additional studies on forage seed crops-integrated production systems and inclusion in priority sector policies would further support diversified cropping systems strategies and benefits for producers.
Funding for this study was provided by Agriculture and Agri-Food Canada.
Nityananda Khanal (2023). Integration of perennial forage seed crops for cropping systems resiliency in the Peace River region of western Canada. Canadian Journal of Plant Science, OPEN ACCESS https://doi.org/10.1139/cjps-2022-0125
Photo by Keaton Freel.
