With extreme cold temperatures continuing across Ontario, when should growers resume planting soybeans?
Planting came to a halt late last week as Ontario finds itself in the grip of extended cold daytime and nighttime temperatures. Snow covered parts of the province during the weekend and into Monday. And there’s more to come — some areas will see nighttime lows of minus 7 degrees C.
“It’s been so cold for so long. Who would have predicted this?” asks Horst Bohner, soybean specialist for Ontario Ministry of Agriculture, Food and Rural Affairs. He says growers need to assess weather risks before they roll planters back into fields this week. He notes that soybean vigour can be significantly reduced when planting into cold soils. The other consideration is a forecast rain for later this week. Do growers plant now into fit but very cold soils or risk being shut out of fields by an approaching rain event?
Bohner believes the best strategy is to approach fields on a case-by-case basis. “If the field is clay soil, it may not dry out for a month — then I would take the risk of planting even though it’s cold,” says Bohner, noting that with better temperatures on the way, rain later this week will be much warmer than last weekend’s snow.
What about sandy soils? That’s a different story, says Bohner. “If it’s a sandy soil that dries out pretty quick… I’m not comfortable planting soybeans when it’s going to be minus 5 or minus 7.”
Bohner also reports that early-planted soybeans are hanging tough, but they are in desperate need of heat. He says soybeans he planted on April 22 are healthy, but they are extremely stressed. “If we don’t get some heat by the end of the week they’re in trouble.”
If those April soybeans do make it will they have sufficient vigour to withstand another weather curveball? How about frost? In this tweet, University of Guelph’s Dave Hooker notes there is evidence that early-planted soybeans can withstand a May frost.
— Dave Hooker (@cropdoc2) April 7, 2012
Check out Soybean School for more on planting soybeans into cold soils:
Soybeans frozen above cotyledon in East ON, May 2008, survived and produced similar yield to soybeans in non damaged part of the field. Few plants frozen below the cotyledon died. pic.twitter.com/JfzHFMn3pM
— Gilles Quesnel (@GillesQuesnel) May 12, 2020