Water stress and nutrient deficiency
Finally, in some situations as the soil dries out the distance might become so large that the ion is not available to the plant at all (as represented by the ion closest to the bottom of Figure 2). This situation is what we are seeing in many fields, which have adequate potassium levels, but as far as the plant is concerned, the nutrient is too far out of reach.
While irrigation is the only option for solving the drought problems we are seeing in much of the state, this year can teach us some important lessons. I recommend for the future that you minimize the effect of drought by ensuring that whatever water is present in the soil is protected to be used by the crop. Some farmers have seen firsthand this year how much water weeds can take up when not treated early in the season. Similarly, too much tillage has in some situations caused unnecessary water evaporation from the soil, and those fields are running out of water sooner than fields that were managed more carefully.