(1) Generally speaking the permeability of water through the soil diminishes fairly in the presence of Promoloid in the field soils and increases in the muddy rice field soils.
(2) On the contrary the permeability of water containing ammonium sulfate increases in the presence of Promoloid in the former case and diminishes in the latter case.
This is because it easily absorbs rain, fertilizers and will keep out probably against the decomposition of salt near the surface and its outflow.
(3) The Promoloid easily absorbs ammonium and potassium salts from the solution and reserves them in the soil. When the contents of ammonium and potassium ions in the filtrates were compared, they were by far the less in those come from the soils given with Promoloid. Hence it assists the absorption of manures through roots and give the favorable effects for the growth of plants.
(4) The surface of soils to which the Promoloid was administered, becomes generally very coarse, so it will help the entrance of air and rain into the soil.
The author is indebted to Prof. Dr. Y. Shibata, Dr. M. Fukui, and Dr. M. Namba in the research laboratory, Asahi Glass Company, for their kind advices and to Mr. U. Sakurai, Professor of Physics in the Keio Medical College, for his kind assistance.
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