Are we really seeing K-deficient corn, soybean?
The best action at this point is to look for clues that may help with determining how best to solve or minimize any future K deficiency. Take note of the general condition of the roots and the physical condition of the soil, and collect soil samples for K analysis from adjacent areas with seemingly normal growth and K-deficiency symptoms. If the deficiency is not extreme and is caused by dry conditions, the crop likely will recover with little or no yield reduction once there is sufficient rain. Most fields have areas that are more severely affected than others; it would be advisable to mark those areas with a handheld global positioning system (GPS) and go back after harvest to sample the soil and to target the area with variable rate applications if deemed necessary.