Soybeans are produced in nearly all of Kentucky's soil physiographic regions. Soybean response to potassium (K) fertilization and soil test Kvaries with soil type and location. This variation may be associated with the wide range in soil chemical and mineralogical properties among the different regions. Of particular interest are differences in that level of soil test Kat which no further yield response to K fertilizer application would be expected. The main objective of this work was to evaluate the soil K-soybean response relationship on three different field sites where soybean yields were increased by fertilizer K. Several measures of soil K availability were related to soybean yield.
Grove, John H.; Thom, William O.; Murdock, Lloyd W.; and Herbek, James H., "Response of Soybeans to Available Potassium in Three Kentucky Soils" (1990). Agronomy Notes. 53.