The rule of thumb for planting soybeans in Western Canada has generally been to wait until the soil is 10 degrees C — often after canola is in the ground, but there are a number of reasons, including historical yield data, that suggest the crop would benefit from earlier planting.
This Soybean School episode, recorded in a field near Winkler, Manitoba on Star Wars Day (May the 4th), features Jedi agronomist Jason Voogt of Field 2 Field Agronomy and Jeanette Gaultier of BASF, discussing the reasons why it makes sense to plant soybeans in the first half of May.
Crop insurance data in Manitoba from 2007 to 2021 shows yield potential dropping from 109 per cent to 101 per cent by the third week of May. “Your optimum soybean yield potential was achieved in those first couple weeks of May and then dropped after that,” notes Voogt.
One reason could be that planting early helps get soybeans up and growing during the longest days of the year in June, encouraging more node development, which results in more pods per plant, he explains.
From a whole-farm perspective, there are also reasons to wait on planting canola due to flea beetle pressure when temperatures are cool, notes Gaultier. “Although canola does manage cool soils well, we definitely see the benefits, especially when there’s pest pressure, like flea beetles, to getting that canola out of the ground as quickly as possible.”
Check out the video below for more on soybean planting timing, soil temperatures, frost risk and more, with Jeanette Gaultier and Jason Voogt: