Seeding has been late from the gate across the province, but there is still time for yields to finish with the front-runners, provincial extension agronomists said last week.
Crops planted the third week of May can still achieve close to their full yield potential, although that potential will decline from now on, say crop experts with Manitoba Agriculture, Food and Rural Development (MAFRD).
“I don’t think it’s too late to expect good yields,” MAFRD soil fertility specialist John Heard said during a webinar May 14. “I would maybe give up on the exceptional yields we had last year, but I’m not saying we’re into low yields yet.”
Heard said farmers should think carefully before cutting back on crop nutrients, despite seeding a bit later than they would prefer (see sidebar). And he said they shouldn’t cut their seeding rate.
And if corn was in the seeding plan, it’s still not too late, MAFRD cereal specialist Pam de Rocquigny said May 15 during another webinar.
“The yield potential is still there for corn seeded into that third week of May,” she said. “Once we get into the last week of May we see yields drop off a little bit more. But once again based on your risk area there could still be some good yields out there.”
During the five years ending in 2012, 89 per cent of Manitoba’s corn crop was planted by the third week of May and 98 per cent by the fourth week, crop insurance records show.
When seeding any crop late into cool, wet soils, it’s important to make the best of it, de Rocquigny said. A good seedbed is critical. Don’t “mud” the seed in or plant in cloddy soil, she said. Cut seeding speed to avoid seeding corn too deeply.
Ideally soil should be 10 C at planting depth. That should allow plants to emerge six to 10 days after planting.
Colder soils will slow emergence, leaving seedlings less vigorous and more vulnerable to disease. Seed treatments can help protect the seed and seedlings, de Rocquigny said.
Fields heavy in crop residue will remain colder longer. And light-textured soils will cool more during cold weather than heavier soils.
Seeding rates need to be adjusted so farmers achieve the plant population they are aiming for, she said. Germination rates and expected plant mortality are part of the calculation. Seeding rates should be bumped up if crops are expected to be under stress.
Research has shown an uneven crop can hurt yield more than a low plant stand. When 17 per cent of plants were delayed by two leaves total yield was cut by four per cent, one of de Rocquigny’s slides showed.
Crops delayed by four leaves resulted in yield losses of eight per cent.
“We definitely want to optimize germination and emergence and therefore stand establishment,” she said. “This is critical for successful corn production and maximizing your yield potential. And we want to scout fields more frequently after planting… and see what can be learned from 2014.”
Stand establishment is equally important for canola, MAFRD oilseed specialist Anastasia Kubinec said. Canola will germinate with soil temperatures of 5 C. As of May 15 only one of MAFRD’s weather stations — Deloraine at 4.7 C — was that high.
Canola should be seeded one-half to one inch deep, Kubinec said. Reduced seeding speed helps ensure that. One study showed seeding at three miles per hour the average seeding depth was three-quarters of an inch and varied between three-quarters and 1.25 inches.
At four miles per hour the depth averaged one inch and varied between one-half inch and 1.5.
At five miles per hour the depth averaged 1.5 inches and varied between one-quarter and 3.25 inches.
It doesn’t matter what type of seeder is used — the faster the speed, the more variable the seeding depth, she said.
Some farmers broadcast canola seed, especially if seeding has been delayed by wet soils. It doesn’t often work well for first-time farmers, Kubinec said. Good seed-to-soil contact is critical, which means harrowing is required after spreading. Then rain is required.
“If it’s too wet to get across with the seeder it’s probably too wet to get across with a set of harrows, so don’t broadcast,” Kubinec said.
Broadcast seeding often results in variable emergence, especially if rain is delayed. A crop varying in maturity makes weed and disease control harder and harvesting too.
Canola seeded by air can potentially be insured by the Manitoba Agricultural Services Corporation (MASC) so long as “it is incorporated into the soil by mechanical means and the crop establishes to a level that is equal to or greater than the insured producer’s coverage,” MASC’s website states.
“The incorporation date will be deemed to be the seeding date, with all aerial-seeded acreage required to be reported on the Seeded Acreage Report by June 22.”