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University of Manitoba Faculty of Agricultural and Food Sciences Department of Plant Science

On-Farm Soybean Cultivar Evaluation
for Suitability to Organic Production
in Southern Manitoba

By Michelle Carkner (

The objective of this research was to evaluate the performance of 12 non-GM short-season soybean cultivars on organic farms in Manitoba.

One of the qualities given special attention to was weed competitiveness. Past literature has pointed to early vigour as an important indication of cultivar competitiveness in cereals and legume grain crops. Therefore, cultivars with increased biomass and height early in the season may be more competitive with weeds.

The research compared 12 non-GM short-season soybean cultivars sourced across Canada and North Dakota, and took place at six locations (Carman, Elie, St. Pierre-Jolys, Somerset, Swan Lake, and Woodmore) in southern Manitoba between 2014 and 2015.

Stand density, early (V3) (approx. first week of July) and late (R5) (approx. second week of August) soybean and weed biomass and height, pod height, 100-seed weight, and yield from weedy and weed-free sub-plots were recorded.

Read the report (PDF).


High organic soybean yields are attainable in southern Manitoba, but this hinges on the ability for proper weed management and environmental conditions. See organic soybean weed management experiment results our lab has done here.

Soybeans are not very competitive against cool season weeds such as wild mustard or wild oat, but may be able to compete against warm season weeds such as redroot pigweed fairly well. If an organic farmer is planting soybeans in a known wild mustard problem area, they should have a very good weed control program in place.

While past research has pointed to choosing soybean cultivars that are competitive at early growth, this work found that on average, cultivars that were most vigorous at early growth were usually the lowest yielding at most sites. All organic farmers should keep relative maturity in mind to avoid frost damage.

Read the report (PDF).

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This page created September 2016.