Weather, an important factor for soybean seedlings

The weather also plays a key role, notes Denise McWilliams, agronomist with the University of Minnesota Extension Service.

"Cool, wet conditions can cause soybean seedlings to die while emerging in water-saturated areas of a field." says McWilliams. "This is usually due to damping off, a symptom caused by several diseases. If damping off doesn't kill seedlings, it is likely to delay seedling emergence."

McWilliams says temperatures below 60 degrees, water-saturated soils and sealed soil surfaces are stresses on soybeans that can contribute to damping off. Deep planting also can play a role. She recommends a planting depth for soybeans of one to one and one-half inches, with a maximum depth of two inches.

McWilliams cites a University of Illinois study of relative emergence of soybeans planted at different depths. The one-inch depth had the greatest emergence and was set at 100% for comparison purposes. The relative emergence for the three-fourths inch planting depth was 85.5% of maximum. At one and one-half inches, emergence was 99.5% of maximum, and at two and one-half inches emergence was 55.2%.

"Poor quality seed or even roughly-handled seed with cracked or discolored seed coats can help cause damping off," says McWilliams. "Move soybeans carefully in cold weather, especially when loading or unloading in bags or running beans through augers. Consider brush augers when moving soybean seed used for planting."