Potential Potassium Buffer Capacity of Kamchatka Volcanic Soils

The volcanic soils of Kamchatka are characterized by low and very low values of their potential potassium buffer capacity. The largest amount of readily exchangeable potassium (-Delta K(0)) is observed in the surface layers of the natural soils and is due to the active biogenic accumulation. The soddy horizons have a high content of strongly fixed potassium (K(X)). The main factors determining the content of the labile potassium and its mobility are the contents of physical clay, humus, and exchangeable potassium. The extremely nonuniform distribution of all the potassium status parameters throughout the soil profile reflects the discrete character of the volcanic pedogenesis. The low values of the potential buffer capacity for the potassium (PBC(K)) at the high values of the equilibrium potassium potential (AR(0)) and the medium content of the labile potassium in the light-textured synlithogenic soils simultaneously indicate both the good potassium supply of the plants and the incapability of the soils to resist potassium exhaustion under agricultural production conditions for a long time. DOI: 10.1134/S1064229311030215