干旱区滴灌棉田冻融季土壤水热盐分布规律研究

摘要

[目的]研究滴灌棉田冻融期及其前后水热盐分布规律.[方法]实验以野外实测和室内试验数据为基础,分析水热盐在干旱区滴灌棉田冻融季土壤各层中分布特征.[结果]表层土壤11月下旬开始冻结,到翌年2月上旬达到最大冻结深度,4月上旬土壤完全融通,冻融期5 cm深处土壤温度变幅为19.95℃,170 cm深处变幅为10.25℃;0～60 cm土层2009年11月29日～2010年2月11日含水量和含盐量冻结过程中都呈上升趋势,2010年2月11日～4月21日为融化期,土壤垂直含水量和含盐量分布表现出复杂的变化方式,60～200 cm土壤水盐垂直分布变化不大;土壤水分与盐分时间变异特征表现为:冻融期土壤表层变异性大于底层,0～80cm水分变异程度大于盐分,80～200 cm水盐变异系数差异不大,变异性低.[结论]为冻融季土壤水热盐分布进一步研究提供参考,对盐渍土的改良、农业灌溉等相关问题的研究有一定参考价值.%[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 19.95 ℃ and 10.25 ℃ 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 2lth, 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 .