Estimation of soil water, heat and nitrate dynamics during soil freezing and thawing with meltwater infiltration

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We simultaneously measured soil water retention and soil freezing curves and investigated their similarity and hysteresis. We succeeded in direct measurement of soil water potential in frozen soils to confirm the relationship estimated by Clausius-Clapeyron equation, and noted the effect of non-equilibrium growth of ice crystal in soil pores. We also performed directional column freezing experiments and showed the water, heat and nitrate transport during soil freezing/thawing and meltwater infiltration into frozen soils. Furthermore, we microscopically observed profiles of redox potential and dissolved oxygen near soil surface, and showed formation of reduced and reoxidized layers in soil columns under various infiltration rate.