Determining the optimum seeding window for soybeans in Manitoba
University of Manitoba, MPGA, Kristen MacMillan
The objectives of this study were to determine the optimum seeding window for soybeans across
Manitoba growing regions.
Final results and recommendations for the Soybean seeding window will be made available during the 2020 growing season.
Soybean is an important legume crop that contains significant amounts of isoflavone compounds which play a crucial role in human health (Al-Tawaha and Seguin, 2006). Soybean production on the Prairies is mainly limited by the cool short growing season that characterize this region. There is great potential for increasing total area under production but timing of seed establishment is crucial in achieving profitable yields. Traditional recommendations are to plant soybeans when soil temperature has warmed to at least 10°C, which is typically May 15-25 in Manitoba (Manitoba Agriculture). However, farmers have started to seed soybeans earlier (Page et al., 2019) and recent work by Dr. Yvonne Lawley and Cassandra Tkachuk (2017) supports this trend. They evaluated seeding dates across a range of soil temperatures from 6 to 14°C in 2014 and 2015; the earliest seeding dates maximized yield regardless of soil temperature and it was concluded that calendar date is a superior indicator. To update seeding date recommendations across a wider range of environments and using defined calendar dates, this study was initiated at Arborg, Carman, Dauphin and Melita in 2017 and continued through 2019.