Strategies to reduce chemical fertilizer inputs and improve soil health and ecosystem services in mixed crop-livestock systems
By Dr. Akim Omokanye and Johanna Murray | Peace Country Beef & Forage Association
A farm’s profitability often depends on producing enough crop per acre to keep production costs below selling price. The recent AgriProfit Cost and Returns Profiles showed that fertilizer costs constitute up to 30% of the total variable costs for wheat, 12% for peas, and up to 33% for canola. Alternative fertility practices, including the integration of livestock, are one way for producers to manage high fertilizer costs and grain market price volatility.
This project was designed to test several strategies for integrating livestock into crop rotations, in two different regions. The various treatments were implemented in the first year (Year 1 - 2018), followed by a canola crop (Year 2 - 2019), and then a wheat crop (Year 3 - 2020). Peace Country Beef & Forage Association (PCBFA) managed a trial site in Fairview (Peace Country), and Chinook Applied Research Association (CARA) managed a site in Sedalia (Special Areas). In total, seven crop rotation treatments were evaluated by PCBFA and CARA’s researchers on a wide range of factors, including yield, grain protein, and soil quality indicators, as well as a benefit:cost ratio (BCR).
Table 1: Seven different rotational cropping strategies that integrate livestock and annual forages into the cash cropping system studied.
Fertilizer application in years 2 and 3 was based on soil test recommendations for average canola and wheat yield at each location.
Cropping treatments impacted canola seed yield in year 2 of the rotation at both sites. No data was available for the rolled CCC at site 1 because of poor seed-soil contact. However, the overall results in Fairview showed that Barley with Penergetic and Barley with manure had significantly greater yield than other cropping treatments. At Sedalia, Barley with Penergetic, Barley with Manure, and Rolled CCC produced significantly higher canola seed yield than other treatments.
In year 3, the treatments showed no significant yield impact at Sedalia. However, the wheat grain yield from both the Barley with Manure and Rolled CCC treatments at Fairview indicated that there were still some effects from the year 1 treatments. It seems that the grazing treatments (Grazed CCC and Swath Grazed CCC) did not deposit enough manure to provide any lasting impact on the subsequent crops.
In Fairview, the most fertility savings compared to the conventional P-C-W rotation came from the Barley with Manure treatment. Other notable fertility improvements were found in the rolled CCC (for at least 2 years) and grazed CCC (particularly in the year following). At Sedalia, the highest nutrient credit came from the Rolled CCC, followed by annual application of Penergetic K&P and Barley with Manure.
An economic analysis was carried out for years 2 (canola) and 3 (wheat) of the cropping treatments, using the total variable costs and total revenue. The benefit:cost ratio (BCR) analyses were compared to a standard index of 1:1 to assess the performance of the cropping treatments. The higher the BCR, the better the economic and management efficiency of the treatment.
Prices used for the benefit:cost ratio are based on a combination of “pre-purchase” prices and fertilizer cost indications for spring 2021. The BCR was generally greater than 1, indicating that the cropping treatments’ benefits outweighed the costs.
At Fairview, Barley with Manure had the highest BCR, returning $1.84 on every $1.00 spent in year 2 and $2.00 on every $1.00 spent in year 3. At Sedalia, Barley with Manure and Barley with Penergetic returned $1.83-$1.98 on every $1.00, while conventional P-C-W (control) yielded only $1.40 on every $1.00.
Identifying alternative practices that could reduce the need for chemical fertilizer and thus reduce the cost of production, while maintaining yield and quality, was the main objective of this study. In general, three treatments stand out as providing improvement in canola and wheat yield: barley with manure, a rolled down cover crop cocktail and the annual application of Penergetic K and P for seed treatment and foliar application. The application of cattle manure prior to seeding in year 1 of a 3-year cropping rotation had a consistent economic effect, regardless of site location or soil type in this study.
Complete results of this trial will be submitted to a scientific journal, for more information on results, or to read interim reports, check out www.peacecountrybeef.ca/research or contact PCBFA at email@example.com.
Lead Researcher: Dr. Akim Omokanye (Peace Country Beef & Forage Association)
Collaborators: Liisa (Vihvelin) Jeffrey and Buthaina Al-Maqtari (Peace Country Beef & Forage Association), Dr. Yamily Zavala and Dianne Westerlund (Chinook Applied Research Association).
This project (Project No. 2018F146R) was jointly funded by Alberta Agriculture and Forestry, Alberta Wheat Commission, and Alberta Canola Producers Commission. The project was also supported by the Municipal District of Fairview, the Special Areas Board, Penergetic Canada, DuPont Pioneer, Grande Prairie Regional College, Clear Hills Colony, and Allan McLachlan.