Organic production tools for field peas: are cultivar mixtures more competitive with weeds?
Within Saskatchewan’s organic industry there is a need for improved tools to minimize yield losses due to weeds. Cultivar mixtures may improve the ability of organic pulse crops to suppress weeds and maintain yields in the presence of weeds. While semileafless peas are known for their lodging resistance and high yield potential in the absence of weeds, conventional peas may provide better weed suppression and yield stability in the presence of weeds. A replicated field experiment was conducted at two organic field sites to test the hypothesis that cultivar mixtures of conventional and semileafless field pea would differ in weed suppression and yields. The experiment tested factorial combinations of five ratios of semileafless pea cultivar CDC Dakota and conventional cultivar CDC Sonata (0:100, 25:75, 50:50, 75:25, and 100:0, respectively), and two seeding rates (conventional and organic recommended). Plots were monitored for crop and weed emergence, biomass, and yields. Significant differences were observed among the different ratios of semileafless and conventional field pea. Results indicate that the semileafless cultivar was more competitive with weeds than the conventional. As the canopy composition progressed from a pure conventional canopy towards increasing percentages of semileafless pea in the mixture, total weed biomass decreased, and total crop yields increased. It was concluded that while no additional weed suppression or yield benefits were seen compared with growing the more strongly competitive semileafless cultivar alone, cultivar mixtures reduced the risk associated with growing unfamiliar or less competitive cultivars by stabilizing weed suppression and crop yields at a level between the two components of the mixture.
crop weed competition
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