Abstract
The object of paper is to examine the chemical composition of mud taken from the bottom of river in Kojima polder, and the effects of iron sulfides in the mud on the change of reaction and soluble salts after they are applied to the field. The content of FeS in the fresh mud lies botween 0.025 and 1.491 per cent, and that of FeS_2 lies between 0.197 and 1.089 per cent as S0_3. In most of muds, the original pH values of fresh samples become extremely acid, ranging from pH 2.6 to pH 5.0,after the incubation at 30° under the condition of the moisture content of field capacity for four weeks. Total solids and water soluble sulfates are increased greatly in the incubated samples. It is concluded that the polder mud must be weathered for so sufficient a time as the oxidized products of iron sulfides are washed out by rain water, before it is applied to the field.
