A simple approach to assessing soybean plant stands


Soybean planting is marching on in Ontario. Acres planted across the province vary depending on soil type, but the consensus is, the crop has passed the 50 per cent planted mark and growers will be pushing to plant the remainder of the crop by month end.

For many growers, the job now is to assess the quality of their plant stands. Ontario Ministry of Agriculture, Food and Rural Affairs soybean specialist, Horst Bohner, admits that assessing soybeans at emergence can be challenging. He points to a field test plot he seeded on May 11, to illustrate the challenge growers experience. Even though he did everything perfectly — the seed was precision planted 1.75 inches deep at 3.5 mph in a nicely worked, fit field — he still observed considerable variability in emergence.

“Soybeans just do not pop up like little soldiers,” says Bohner. “Fortunately it doesn’t matter so much in soybeans, but it is a little frustrating,” he noted during a Tuesday morning Exeter/Mount Forest virtual agribusiness breakfast meeting. He expects the remaining seed in the plot to emerge over the next week, but adds that in clay soils seed can take up to six weeks to emerge.

Bohner expects soybeans in his test plot to continue to emerge over the next week.

When it comes to assessing plant stands, Bohner notes there are all kinds of charts and methods available but he says there is no need to complicate the process. He shared a simple method based on the number of square feet in an acre — 43,560.

“Basically, one plant per square foot is not enough; two plants per square foot is okay (no replant is required); and three plants per square foot is a normal stand,” he noted.

But there are areas of the province where soil types and local growing conditions would have to be factored into the assessment, says Bohner. The heavier clay soil in the Niagara peninsula is a good example. “We’ve kind of landed on 110,000 plants on clay soils as a minimum, which is more than the 88,000” growers will get with two plants per square foot.

See Related: Soybean School: Assessing stand establishment 30 days after emergence


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