Wednesday June 1st was the third virtual Northern Breakfast Meeting. The last meeting will be held on Wednesday June 15th at 8:30am EDT and we will be joined by Ben Rosser, OMAFRA Corn Specialist.
This week we heard from Horst Bohner, OMAFRA Soybean Specialist. Horst touched on a few soybeans topics, as follows:
Seeding Depth and Seeding Date:
The ideal soybean seeding depth is 1.5”. At depths of 2.5” rates of emergence are much lower, especially in clay soils, and significant gaps in the stand are visible. Soybeans have an incredible ability to push through crust but the deeper you plant, the lower the ability of the seedlings to push. Soybeans may still emerge up to 6 weeks after planting when dry soils are the cause of slow emergence, but if there is crust at the surface it is unlikely more plants will emerge after 1 month in the ground. Rolling after seeding can increase the risk of crusting. If you are planning to roll the field it is recommended to do so after emergence, ideally at the 1st trifoliate leaf stage.
Seeding soybeans in June reduces yield potential. In trials conducted in Ontario, the best yields were achieved with May planting dates, and yields from April planting dates were a couple bushels behind. Seeding in June reduced yields by as much as 10 bu/ac.
Populations and Row Spacing:
Many producers in southern regions grow soybeans on 30” row spacings, and this is often because the producers want to use of row unit planters that seed with greater precision. There are also lower seeding rates used on wider rows. However, as row spacing increases beyond 20” yields will decline. In northern regions, it is recommended to grow soybeans on 15” rows. Unlike corn, in soybeans the consistency of spacing between plants is not overly important, which is another factor in why drills and air seeders are adequate and row unit planters are not necessary for success with soybeans.
Populations should be 140,000 plants/ac for 100% yield potential, and between 140,000 and 150,000 plants/ac on heavier soils. Trials in Ontario have shown that at populations below 140,000 plants/ac a few bushels are lost. Yield potential really starts to drop off at populations below 100,000 plants/acre. It is commonly recommended in the US that seeding rates of 120,000 seeds/ac are adequate, but with typical rates of emergence this puts populations at about 80,000 plants/ac. In parts of the US plants will get larger than we see here, so in Ontario higher seeding rates are recommended for adequate stands.
A producer raised this question: What is the best way to manage white mould on a mould-prone field where soybeans are typically drilled on 7.5” rows? If you have a field where there is always white mould pressure, the main goal should be to take multiple strategies to mitigate it. Do not apply nitrogen fertilizer, seek out a variety with white mould tolerance, lower the seeding rate, and seed on 15” rows. In southern Ontario we would likely switch to 30” rows, but in a 2400 heat unit region 15” spacing is likely best and a maximum of 140,000 seeds/ac. Plan to apply a preventative fungicide and maybe 2 passes of fungicide. In a 1 pass fungicide system the ideal fungicide timing is at R2.5, which is prior to small pods forming on the plant. Start preparing for fungicide at early R2 because growth advances quickly. If you are planning on two passes of fungicide, the first could go on at late R1, after 50% of plants have one open flower, and the second pass about 14 days later.
Another scenario was mentioned where a field was accidentally seeded at a very high populations – around 300,000 plants/ac – on 15” rows and is now at the unifoliate stage. The field has a history of white mould so a 2-pass fungicide application is planned. Trials have been done at as high as 600,000 plants/ac, and it as suggested that although the population is high this example scenario is not outrageous. It was not recommended to try and thin the population using a rotary hoe or planter, and that some thinning may occur through soybean competition. There is a risk of lodging at high populations.
Conditions have been wet since the meeting two weeks ago, and there is more rain in the forecast. Land that is not tiled has not been planted yet and isn’t drying out. Fertilizer trucks have been seen heading north, so there is still some field activity in the region. Anything planted now will be cut for feed because they’ll run out of time at the end of the season for grain crops. Overall, planting is approximately 80% complete.
In this region producers feel fortunate to have had conditions that are not too wet or dry, and not too hot or cold. Seeding has been complete for a while now, and they are halfway through herbicide applications. Alfalfa is at first bud and will be cut soon and orchard grass is heading.
Thunder Bay District
There was significant winter kill in the winter wheat and winter rye and these fields have been terminated to plant other crops, including canola or corn. There was some winterkill in alfalfa mainly in the lower spots of the fields. Seeding started during the last week of May. Maximum seeding completed up to May 29 by a single producer was 320 acres of canola and 95 acres of corn. Seeding by other producers ranged from zero to 100 acres (corn, canola and spring wheat). It rained on May 30 again and seeding stopped but some producers may be able to resume today. Quite a few producers have planned to seed sorghum-sudangrass this year.
Seeding has not yet begun at the research station in Thunder Bay. Fields had to be cleared from the unharvested crops last year and the volunteer crops coming up were sprayed with Roundup. Sadly, the main Field Technician, Blaine Tomeck has fallen ill due to cancer. Blaine has been a strong pillar at LUARS and it will be difficult to fill that role with someone new.
Rainy River District
It has continued to be extremely wet across the region with record breaking rainfall some areas and flooding in both rural and urban areas. Producers are very frustrated and have completed only about 20% of their planting of canola and soybeans. There were a few days of drying last week but there has been more rain in the past 3 days. Some deadlines for crop insurance have passed but producers will likely continue to seed what they can. The spring wheat planting deadline has been extended to June 5th.