Objective: To study the regularities of the distribution of water, temperature and salinity in drip irrigation cotton field during freeze-thaw season. Method: Based on the data of field survey and laboratory test, this experiment analyzed water, temperature and salinity of each layer of the soil in arid drip irrigation cotton field within the freeze-thaw season. Result: The result showed that the surface soil begins to freeze in late November, and reaches maximum freezing depth in early February, the soil is completely melted in early April. The amplitude of soil temperature is respectively 19.95degreesC and 10.25degreesC at 5 cm and 170 cm depth. In the process of soil freezing, the soil water and salinity show ascendant trend within 0-60 cm depth from November 29th, 2009 to February 11th, 2010. In melting process (February 11th, 2010 April 21th, 2010), the vertical change of soil water and salinity is complicated. Water-salinity vertical distribution have little change within 60-200 cm. The features of temporal variability coefficient of soil water and salinity showed as follow: the variability coefficient of surface soil salinity is greater than bottom during the freeze-thaw period, the change of soil water is greater than soil salinity within 0-80 cm, the temporal variability coefficient of the soil water and salinity have low variability within 80-200 cm. Conclusion: The present study provided useful data for further research on soil water, temperature and salinity distribution during freeze-thaw period, and have certain reference value on soil improvement, agricultural irrigation and other related issues.
