不同钠质化程度土壤水分特征曲线及土体收缩特征  

Water Characteristic Curve and Shrinkage Characteristics of Different Sodification Degree

作　　者：常凯 邢旭光[1] CHANG Kai;XING Xuguang(Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of Ministry of Education,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《灌溉排水学报》2021年第10期131-136,144,共7页Journal of Irrigation and Drainage

基　　金：国家自然科学基金项目(51809217)。

摘　　要：【目的】探究钠质化对土壤持水性和收缩特征的影响,【方法】分别以蒸馏水、质量浓度为3、10、20、30 g/L的NaCl溶液(TDS-3、TDS-10、TDS-20、TDS-30)饱和耕作层土壤,测定其土壤水分特征曲线和土体收缩特征曲线,并对不同处理土壤持水能力和收缩特性进行分析。【结果】低钠盐处理(TDS-3)通气、毛管、无效孔隙占比均减少,持水性增强;而高钠盐处理(TDS-10、TDS-20、TDS-30)持水性变弱;各处理有效线缩率与吸力间满足对数关系,土壤收缩量与体积含水率呈负相关关系;三直线模型能较好拟合各处理收缩特征,且收缩过程均可分为超正常段、结构段和伪饱和段。【结论】钠盐溶液对土体孔隙结构产生影响,各孔隙的相对数量发生变化,土体胶粒破坏,水分滞留的难易程度和土体收缩特征发生变化。【Objective】The purpose of this paper is to explore the effect of different sodium on soil water holding capacity and shrinkage characteristics,【Method】The soil was saturated with pure water and NaCl solutions(TDS-3,TDS-10,TDS-20,TDS-30)with concentrations of 3,10,20 and 30 g/L respectively,and the soil water characteristic curve and soil shrinkage characteristic curve were measured.【Result】The results showed that,the degree of sodium had an effect on soil water characteristic curve,low sodium salt(TDS-3)compared with other high salinity treatment and blank treatment,reduced the proportion of ventilation,capillary and void,and enhanced the water holding capacity while high sodium salt treatment(TDS-10,TDS-20,TDS-30)weakened the water holding capacity.the effective linear shrinkage and suction of each treatment met the logarithmic relationship,and the soil shrinkage had a negative correlation with the volume water content;three linear regression analysis showed that the effective linear shrinkage and suction of each treatment met the logarithmic relationship,The model could be divided into three parts:abnormal shrinkage,structural skrinkage and pseudo shrinkage.【Conclusion】Sodium salt solution has an effect on the pore structure of soil,the relative number of each pore changes,the colloidal particles of soil are destroyed,and the difficulty of water retention and soil shrinkage characteristics change.

关 键 词：水分特征曲线 土体收缩特征曲线 毛管孔隙 

分 类 号：S152.7[农业科学—土壤学]