Planting Soybeans Late and Target Populations

The USDA Crop Progress and Condition Report for June 7, 2009 indicates that soybeans planting is 48% completed, well below the 5-year average of 71%. About 32% of the soybean plants had emerged.

Normally, for full season soybeans, we suggest that a final stand of 100,000 plants per acre is sufficient for maximum yield. However, we are getting later into the season. For full season soybeans planted today or later, farmers may want to increase the goal of a final stand to 140,000 plants per acre. Double-crop soybeans (soybeans planted into wheat stubble) should attempt to get a final stand near 160,000 plants per acre. In addition, any soybeans being planted today or later should be in row widths of 15 inches or less.

The recommendation for the higher target population and narrow rows, is because a fundamental principle for higer yields is getting full canopy closure when the soybeans flower. These later planting dates require more soybean plants per acre and narrow rows to get to full canopy closure by the time the soybeans flower.