When Will New Soybean Yield Plateau Be Achieved? As someone who has been involved in the soybean sector for more than 30 years I have long been interested in the relatively slow growth in U.S. soybean yields. Clearly there has been yield growth, but it has been irregular owing to weather and other factors. In a few cases average yields increased sharply from one year to the next with inordinate new yield highs being reached in 1984, 1992 and 1994. The average national yield in 1994 reached 41.4 bushels/acre. That yield was not surpassed until 2004 when the national average yield reached 42.2 bushels/acre. However, the 2004 average yield exceeded in five of the following eight years with the all-time high set in 2009 at 44 bushels/acre...