Coordinating agronomist: Marika Dewar-Norosky
Organization: Manitoba Organics
Practice: Nitrogen management
Trial started: Spring 2026
Barrier: While agronomically effective in supplying nitrogen, full season green manure years remove land from cash-crop production so they can be perceived as a financial burden. As a result, farmers (organic and non-organic) are hesitant to extend rotations or adopt more complex systems without clear, regionally relevant evidence that these practices can maintain yields and support economic viability.
Description: This field scale trial evaluates a two-year intercropping and grazing system aimed at improving nitrogen management and profitability in grain production. More specifically, it compares: 1) an intercropped yellow pea-oat crop (to be harvested, cleaned and sold as two separate cash crops) with an underseeded cover crop of hairy vetch and subterranean clover and 2) a forage pea-oat green manure (with an underseeded cover crop of hairy vetch and subterranean clover) that will either be a) grazed as a termination method or b) plowed down as a termination method. The following year, a spring wheat crop (which will be harvested as the cash crop) will either be 1) monocropped or 2) underseeded with red clover. The trial, which builds on University of Manitoba small-plot research, will measure soil nitrate, yellow pea-oat and spring wheat yield and biomass, and oat-pea forage and green manure biomass. Analysis will also be completed to determine nitrogen availability and economic viability of the intercrop.