Over the last 30 years, soybean yields in the U.S. and Virginia have increased by an average of 0.5 and 0.35 bushels per acre per year, respectively. Virginia soybean variety test results show a similar yield improvement over the last 23 years. When these data are separated by cropping system, the yield improvement of full-season soybean approach an average of 0.6 bushels per acre per year, but yield improvements in a double-cropped system are flat. A more detailed evaluation of these data indicates that most of the full-season yield increase occurred before 1998 and is relatively flat afterwards. More concerning is that double-crop yields have gradually declined until the last two years,...