The ORP value in plow layer and plowsole layer was lower than 300 mV in both the open percolation and
closed percolation models. However, the ORP value in subsoil was more than 300 mV in the open
percolation system, whereas it was lower than 300 mV in the closed percolation system. The ORP value of
more than 300 mV is indicative of oxidising conditionsa and lower than 300 mV indicates reductive
conditions. In principle, soil layers with oxidising conditions promote the accumulation of cadmium in
plant.