The Characteristics of Tea Soils (Part 10)

Abstract

Potassium supplying power of tea soils derived from volcanic ash soil, diluvial red-yellow and "Kuroboku" soil and tertiary yellow soil were examined by the extract method with N-nitric acid and 0.01 N-hydrochloric acid. Furthermore, potassium fixation power of those tea soils were examined by the VOLK'S method.The results were summarized as follows:1. Potassium supplying power of the four tea soils were pressumed as follows by the amounts of N-nitric acid soluble potassium of those tea soils, but that of diluvial "Kuroboku" soil did not show thee difinite tendency.Tertiary yellow soil>diluvial red-yellow soil>volcanic ash soil.Differences of potassium supplying power of soil between tea soil, cultivated soil and uncultivated soil were not abserved.2. From the characteristic potassium release curve of soil leached with 0.01 N-hydrochloric acid, potential potassium supplying power of those tea soils were abserved.Potential potassium supplying power of volcanic ash soil was the smallest and that of red-yellow and tertiary yellow soil was comparatively larger than the other soils. Furthermore, that of "Kuroboku" soil was larger than that of volcanic ash soil, but was presumed to be slightly smaller than that of red-yellow soil and tertiary yellow soil.3. Potassium fixation power of those tea soils was determined. It was observed that potassium fixation power of volcanic ash soil was generally small compared to the other soil and potassium fixation power of soil was not different among the other soils except volcanic ash soil.