干拓地土壌に関する研究(第7報) : 塩成干拓地土壌の生成過程と関連しての硫化鉄の行動について

抄録

It is the purpose of this paper to study the effects of iron sulfides which had been formed in polder soils under an anaerobic condition on the soil forming processes of polder soils of Kojima Bay. The content of FeS_2 in the non-leached halogenetic polder soils is over 0.5% as SO_3 in most of horizons. Iron sulfides in the leached halogenetic polder soils decrease greatly in the upper horizons, ranging from 0.1 to 0.2%, but those of G horizons are 0.5% or more. It is found that iron sulfides are rapidly oxidized in an aerobic condition and their products are easily leached out and the reaction of soils becomes acid as a result of this change. On the contrary, they remain unchanged in an anaerobic condition for a long time. The content of FeS_2 in the polder soils in other polders than Kojima is also much, ranging from 0.167 to 2.553%. It is shown that iron sulfides in the polder soils have a profound influence on the soil forming processes of halogenetic polder soils.