Modeling the effect of antecedent soil water storage on water and heat status in seasonally freezing and thawing agricultural soils

Taking the Inner Mongolia Hetao Irrigation District (IMHID) agricultural production region as a background and based on field data and local meteorological data, the influence of antecedent soil water storage (ASWS) on water and heat status was simulated and analyzed using the SHAW model during the seasonal freezing-thawing period. The results showed that the amount of ASWS prior to soil freezing can influence the depth of freezing and penetration of low temperatures. When ASWS within the surface 1 m is less than or equal to 150 mm, soil water storage (SWS) was always increasing over the winter period. However, for ASWS greater than 150 mm, SWS went through 3 phases: at first it decreased, later it increased, and eventually it decreased again. During soil freezing, the amount of upward water transfer made up the deficit caused by evaporation and percolation for ASWS less than or equal to 150 mm. Conversely, the amount of percolation was greater than that of upward transfer for ASWS greater than 150 mm. During soil thawing, water continued to transfer from lower soil layers to upper layers and overtook evaporation and percolation for ASWS less than or equal to 210 mm. However, the amount of evaporation and percolation was greater than the upward transfer for ASWS larger 210 mm. These results may be used to assist in appropriate irrigation scheme in autumn, agricultural irrigation water management and research on reducing soil secondary salinization. (C) 2013 Elsevier B.V. All rights reserved.