The reason for the yield advantage of rotations is still speculative. Differences in soil nutrients, soil moisture, diseases, insects, weeds, and soil physical properties have all been considered to be responsible for this effect. It was not until the late '70s that a non-nitrogen soybean effect on the following corn crop was substantially documented. Corn after soybeans consistently performed better than second-year corn irrespective of nitrogen fertilization. In previous work done with the soybean-corn rotation, there has never been an evaluation of the potentially different effects of soybean varieties on following corn yields. This study aimed to evaluate whether such differences exist.