Intercropping Legumes with Corn to Extend Winter Grazing

Background

There are many economic benefits to extending grazing season on cow calf operations and corn provides a way to do that. Corn is higher yielding and higher in energy than most perennial forages, but it also has increased costs associated with growing it and although it works well for mature cows, growing animals don’t do as well due to the low protein content. Intercropping other annual forages with corn could help increase the protein content of the stand and may even reduce the amount of fertilizer needed. Limited research has been done in Canada to identify which intercrop species (legumes, grasses, brassicas), fertility rates, row spacing, herbicide strategies, will best adapt this new practice for the Canadian Prairies.

Objectives

• Identify optimal high-protein forage species and nitrogen application rates for intercropping of corn for potential late fall/early winter grazing of beef cattle.
• Seeding strategies to optimize corn intercropping with high protein forage for potential late fall/early winter grazing of beef cattle.
• Evaluate three corn intercropping strategies for potential late fall/early winter grazing of beef cattle across a range of Prairie ecoregions.
• Evaluate animal performance, feed intake, rumen microbial efficiency and grazing behavior of backgrounded cattle or replacement heifers grazed on corn-based pastures in late fall/early winter.
• Economic analysis of intercropping corn for beef cattle grazing.

What they will do

A suite of activities including small plot agronomy trials, a large-scale pasture grazing study, and an economic study will be used to develop strategies for intercropping corn with high-protein forages to improve overall yield, nutritive value, and profitability of fall and winter beef cattle grazing in western Canada. Small plot experiments will identify the most promising high protein intercrop species to be grown with corn for fall/winter grazing. The six species treatments selected are corn intercropped with: 1) Italian ryegrass, 2) hairy vetch, 3) a forage brassica, 4) crimson clover, 5) a mixture of the four intercrop species, and 6) a no-intercrop control treatment of corn. These six species treatments will be compared at two nitrogen (N) fertilizer rates: 1) 18 kg/ac of N and 2) 45 kg/ac of N. In a second small plot experiment, three key management factors will be evaluated: corn row spacing, timing of intercrop seeding, and seeding method. Management treatments will include a comparison of corn grown on standard 30 inch spacing with 60 inch spacing that would give more room for the high-protein intercrop mixture to grow earlier in the growing season. Seeding timing treatments will include 1) seeding on the same date as the corn and 2) seeding at V4 after last herbicide application. Two seeding methods will be compared for each seeding timing: 1) drilled between rows using an interseeder, and 2) broadcast seeding.

As our project partners represent producer members across the three prairie provinces of Manitoba, Saskatchewan, and Alberta, there is a significant interest in understanding how corn intercrop systems will perform across this large range of growing conditions. In partnership with local producer-led applied research organizations in all three provinces, we propose to test the most promising intercropped treatments across a wide range of Prairie growing conditions. These same 3 combinations will be grown for a grazing trial in Manitoba, where large pastures will be grazed by backgrounding steers or replacement heifers, and agronomic and animal data will be collected. The economic portion of this project will compare representative beef operations to explore the implications of the move away from confined feeding/wintering and assess the impacts on profitability associated with the proposed corn intercrop grazing strategies.

Implications

There is consensus among beef producers across the Prairies that finding innovative strategies to extend fall grazing and to overwinter cattle on the landscape rather than in confined feedlots improves the economic, social, and environmental outcomes of their operations and the beef sector as a whole. Partnering with the beef and forage industry, our multidisciplinary team will explore strategies for combining high-energy corn with novel high protein forage species for flexible extended winter grazing options that lengthen the grazing season and reduce winter feed costs, while meeting animal nutritional requirements under western Canadian winter conditions. Due to the growing interest in intercropping, crop-livestock integration, and regenerative agriculture, these new grazing strategies will enhance the long-term resiliency, adaptability, competitiveness, and profitability of Canadian beef production to enhance food security.