On the Leaching of Calcium in the Tea Soil

Abstract

Leaching of calcium in the tea soils of Fuji humic volcanic ash soil and "Kuroboku" and red yellowish soil derived from Makinohara plateau was investigated with radioactive calcium. These soils were adjusted to 25 or 50% saturation degree of calcium by radioactive calcium and those were treated with distilled water and ammonium acetate solution.By the same method, the difference of calcium leaching among tea soil, uncultivated soil and cultivated soil and the effect of ammonium sulphate on calcium leaching in the soils were examined.The results were summarized as follows.1. Leaching rate of added calcium by distilled water was comparatively higher in volcanic ash soil and "Kuroboku" than in red yellowish soil. Accordingly, the added calcium in red yellowish soil was kept as exchangeable calcium more than in the other soils.2. Leaching rate of added calcium by distilled water in tea soil and uncultivated soil was higher than in cultviated soil and the exchangeable calcium derived from added calcium in tea soil and uncultivated soil was less than in cultivated soil. This tendency was remarkable in the soil of low calcium saturation degree.3. By supplying ammonium sulphate, water soluble calcium increased in each soil. This tendency was remarkable in red yellowish soil.