Traditionally, soybeans in Ontario have been grown without added fertilizer. 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 deficienciey symptoms being observed more often.
This project was set up to assess if added 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.