CONSERVATION TILLAGE EFFECTS ON THE POTASSIUM STATUS OF SOME KENTUCKY SOILS

Changes in the soil K status occurring as a result of shifting from conventional to no-tillage management in selected fields were evaluated in this study. The fields were on loess- and limestone-derived soils in western and central Kentucky and have been under no-tillage management for the last 6 to 16 yr. No-tillage management resulted in a lower overall affinity for K of the exchange sites in all soils. Quantity/intensity plots reflecting the tillage-shift effect on K relationships suggested that the loessial soils could reach K-availability equilibria sooner than the limestone soils due to mineralogical and textural differences. This could mean less fertilizer-K use on loess- than on limestone-derived soils to attain maximum crop yields under no-till management. -from Authors