The authors divided the reclaimed land into three kinds of field conditions; only irrigated field, chemical manure given field and chemical manure and barn yard manure given field; and planted the aquatic rice in each of them. After harvest, we sampled sub-soil from each field and made a study of the Atterberg Limits of the soil. The results are as follows. The chemical manure and barn yard manure given field showed the highest Atterberg Limits, the second was the chemical manure given field and the lowest was the only irrigated field. The contents of organic matter of soil increased in the following order: Chemical manure and barn yard field > Chemical manure field > Only irrigated field. Therefore, it is concluded that the organic matter affects the atterberg Limits. Then the authors studied how the manure, (NH4)2 SO4, KCl, affects the atterberg Limits. In this study, the atterberg Limits of sub-soil soaked in various electiolyte solutions of 1N, 1/2 N, 1/4 N, 1/8 N, and 1/16 N were determined. The atterberg Limits was controlled by the concentration of the solution and was dominantly low in the case of the high concentration.