Effects of seasonal freeze thawing on water and salt movement in saline lands

摘要

Soil salinization is a major obstacle restricting the agricultural development of arid areas, it is also an important factor affecting the stability of the oasis ecological environment(Tian,C.Y.et al.2000).The formation of saline soil is closely related with water and salt movement.In-depth studies on soil water and salt movement mechanism is the theoretical basis for prevention of soil salinizaton and improvement of saline soil (Wang, Z.Q.et al.1993).Seasonal freeze thawing processes are the main driving force for the formation of soil salinization in arid areas(Zhang, D.F.et al.2001).Under the control of temperature, water and salt movement showed a special pattern.Many studies have been done in this field (Thunholm, B.et al.1989;Marion, G.M.1995;Zhang, D.F.et al.2005;Li, R.P.et al.2012;Wang, Y.J.et al.2012), however,the effect of the freezethawing processes on the coupling of soil water and salt and heat regulation mechanism is still unclear.In this study, we chose typical salt barelands in the Manas River basin and measured soil moisture, salinity and temperature dynamic in 160cm soil profile from January to May, 2010.Then we analyzed the regulation effect of the heat transfer on water and salt movement during freezing, thawing, and evaporation period.