Soil conditions and moisture levels are key factors to consider when setting ideal soybean planting depth, but growers should also think about soil type and clay content.
On this episode of the RealAgriculture Soybean School, we visit with Ontario Ministry of Agriculture, Food and Rural Affairs soybean specialist Horst Bohner at the Elgin Soil & Crop Improvement Association research site near St. Thomas, Ont. At this location, high clay levels provide an excellent opportunity to test the impact heavier soil can have on soybean emergence and plant establishment.
In soils with higher clay content, Bohner says growers have to be more mindful of planting too deep because crusting can be an issue when the soil dries out after heavier rains. Deeper planting is more palatable in loamier soils because the seed’s hypocotyl can push longer and emerge stronger when the soil isn’t as tight.
At the Elgin research site, Bohner planted 167,000 seeds per acre in 15-inch rows at depths ranging from surface broadcast to 3 inches deep. At the 1.5 inch depth, 146,000 plants established to lead the trial. As this is Bohner’s standard recommendation, he was not surprised beans at this depth provided the best performance.
Growers often look to plant deeper in the spring when soil moisture is lower in the soil profile. In this trial, Bohner found that soys planted at 2 inches still produced an adequate plant stand (115,000 plants) and even at 2.5 inches an acceptable stand was achieved (100,000 plants).
“At two inches you start to lose some plants and 2.5 would be the absolute maximum depth,” says Bohner.
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