If this year’s early spring is making you itchy to get out there, there may be a lesson in this photo of MAFRD oilseed specialist Anastasia Kubinec seeding canola at the Ian N. Morrison Research Farm at Carman April 5, 2012. Farmers were calling to ask if extra-early seeding was worth the risk, so the plot was a deliberate test for the Crop Diagnostic School.
CDS organizers planted sunflowers, corn, soybeans, canola, wheat, flax, peas and beans on four dates: April 5 and 19, and May 4 and 17.
In August we covered the CDS, and reported:
The CDS site near Carman typically sees the last hard frost (-2 C) somewhere between May 21 and May 25. But this year it came April 26 — which delivered some unexpected results.
“As you can see, some of our earliest planting dates are among the better-looking plots,” Kubinec told participants, while quickly adding the real story is a bit more complex.
“In most of the crops you’ll also see that there’s very little to choose from between the earliest and second-earliest seeding date,” she said.
That’s because the earliest crops were sown into ground that had to warm significantly before the seed germinated and seedlings emerged, Kubinec said. Soil temperature for both the April 5 and April 19 plantings was 5.3 C, and it was only by May 4 that it had warmed up to 9.8 C.
That meant the earliest canola seeding date, for example, saw the seed sit in the ground nearly three full weeks before emergence, while the second earliest saw emergence after just two weeks. The two seeding dates in May saw emergence in just over a week.
“Soil temperature needs to be at a minimum of 6.5 C to 7 C to enable germination,” Kubinec said. “That means the first two treatments were really only getting out of the ground at roughly the same time. In light of this, the question is whether it’s worth the risk to seed that early. I’d say probably not.”