By Sergio Cabello-Leiva and Szilvia Yuja
Soil-borne pathogens are a consistent constraint to soybean production across North Dakota and the northern Great Plains, but management options remain limited. Chemical fumigation is not viable at the field scale and long-term varietal resistance and crop rotation require extended timelines to be effective. Biofumigation using Brassica cover crops has emerged as a biologically-based alternative, relying on the hydrolysis of glucosinolates into isothiocyanates during residue incorporation to suppress soil-borne pathogens (Sennett et al., 2021; Walker et al., 2022).
In North Dakota, winter camelina has already demonstrated the capacity to reduce soybean cyst nematode populations under field conditions (Acharya et al., 2019), supporting the potential for brassica-based biofumigation systems in the region. Beyond disease-related mechanisms, winter-hardy cover crops address additional agronomic challenges common to the Northern Great Plains, including wind erosion, low residue environments, and early-season nitrogen losses. Brassica cover crops actively grow in late fall and early spring, protecting the soil surface, reducing nitrate leaching, increasing soil biological activity, and improving overall system resilience (Blanco-Canqui et al., 2015; Cabello-Leiva et al., 2023).
This is a summary of first-year agronomic results from the Carrington REC, focusing on cover crop establishment, biomass production, nitrogen capture, and soybean yield and stand response. Disease incidence was not measured during this phase, and results are presented as an agronomic evaluation of this emerging biofumigation system.
Wheat was planted in spring 2024 and harvested in August. Winter cover crops were seeded in September 2024 following wheat harvest using a randomized complete block design with four replications. Each treatment was replicated three times within each block. Treatments included (1) Winter Camelina, (2) Pennycress, (3) Cover Crop mix (winter camelina + pennycress), (4) Cover crop mix (winter camelina + pennycress + radish), and (5) No cover crop/control.
Source : ndsu.edu