Author(s): Qihan Qiu; Hiroaki Terasaki; Teruyuki Fukuhara; Ximan Liu
Linked Author(s):
Keywords: Tsunami; Salt-affected paddy; Salt removal; Salt elution; Analytical model
Abstract: Many agricultural lands were seriously damaged by seawater intrusion due to the Tsunami after the Great East Japan Earthquake in 2011. The salt elution method is one of remediation techniques against soil degradation by salinization and soil salinity is eluted from the soil surface to the floodwater spreading on it. Accumulating scientific acknowledges regarding the relation between the eluted salt mass, M, and floodwater depth, 4,, flood duration is indispensable to enhance the salt removal efficiency and to resume farming quickly and reliably. A new analytical model for performance evaluation of the salt elution method is developed in this study. The present model is capable to calculate the increase in the salt concentration in the floodwater and the reduction profile of the salt concentration in the soil due to the salt elution simultaneously. The model accuracy is evaluated by comparing calculated and experiment data of salt concentration from a soil column test under shallow floodwater. It is concluded that the decrease in soil salinity becomes notable towards the soil surface, especially in the top S0mm layer, while the salt concentration in the floodwater increases remarkably near the soil surface. M, is in proportion to /., but the increase rate of M, becomes smaller for higher /.. The analytical results of the soil salt concentration profile and M, are in good agreement with the experimental results when the elution coefficient is the order of 10™*m/h.
Year: 2018