Late August rains and soybean yield potential
Some soybeans were in the flowering and pod set stage at the time of the rain. For the most part, these are double-cropped or full-season maturity group V varieties. These beans have the potential to respond to the rain by retaining and filling pods, thereby increasing seed number. The question then becomes whether plants that just now set pods will have enough time to develop mature pods before the first hard freeze in the fall. In general, it takes a soybean plant about 50-62 days from pod set (R3) to full maturity (R8). At Parsons, in southeast Kansas, the average first frost date is October 23, if pod set began on August 24, this will provide for about 61 days of pod fill before the average first fall freeze.
Soybeans that did not receive rain on August 24-26
Unfortunately, some areas of Kansas got very little rain on August 24-26. Rain is falling in some of these areas of east central Kansas today, August 31. It may or may not be too late at this point. The potential for plants in these areas to respond to rainfall at this time or in the future will again depend upon the plant health and stage of plant development of the crop.