Traditionally, soybeans in Ontario have been grown without added fertilizer unless soil test values are low. Nitrogen is provided by fixation in the nodules of soybean roots, and phosphorus and potassium was only supplied if soil tests were low. In recent years, yields have increased and crop rotations have shortened between soybean crops; this short interval is leading to nutrient deficiency symptoms being observed more often.
This project was designed to assess if fertilizer, in a variety of blends and placements, can increase soybean yields. The project also evaluated what soil types would have the greatest responses based on the existing soil test levels.