Abstract
This study aims to clarify the redox potential and the removal of soluble elements (iron, manganese, potassium, calcium) in a stratified paddy field using a large lysimeter (length 15 m) with an open system percolation in the subsoil. As a result, plow layer and plowsole layer became the closed system percolation for the whole year. At every investigated point (2.5 m, 5.0 m, 10.0 m and 15.0 m) from the atmosphere (edge of the lysimeter), both layers became reduction layers. Subsoil became the open system percolation and oxidation layer at every point.
Four elements in downward water were detected in plow layer and plowsole at every point for the whole year. Iron element and manganese element weren’t detected in downward water of the subsoil at every point for the whole year. Potassium element and calcium element were detected at every point for the whole year and their concentrations in subsoil tend to be higher in the plow layer and plowsol. The concentrations of the four elements in the downward water increased in summer and decreased in winter. When the experiment finished, we found iron and manganese illuvial horizon in the upper subsoil.
