膜下滴灌棉田冻融期土壤水分盐分变化特征

摘要

通过分析2014年11月-2015年3月北疆地区膜下滴灌棉田冻融期土壤盐分、水分与温度变化,探讨了不同土层水热盐在冻融期的变化和耦合关系.结果表明:冻融期土壤表层和深层含水量较高,中间层含水量较低;土壤剖面盐分在0～80 cm呈现层状分布,浅层土壤发生盐分明显累积,土壤盐分变异系数20 cm土层为0.525、40 cm土层为0.257、80 cm土层为1.041.在冻融期,土壤水分盐分沿剖面分布发生明显变化;土水势梯度、土壤温度梯度是冻融期土壤水分盐分迁移的主要因素,土壤水热盐之间变化具有高度的耦合性.%The changes of soil salinity,moisture and temperature of film drip irrigation cotton field in north area from November 2014 to March 2015 were analyzed.Changes of soil water,heat and salt and their coupling relationship during freezing and thawing period were measured.The results revealed that during freezing and thawing period,the water content in the surface and deep soil was higher while middle layer had low water content.Degree of salinity increased with the soil depth,and was significandy enriched in surface soil.During freezing and thawing period,the distribution of water and salinity of soil profile was significantly changed.Soil water potential gradient and soil temperature gradient were the principal factors influencing soil water and salt migration,and soil water,heat and salt changed coordinately.