科尔沁草甸地冻融期土壤水热盐动态迁移规律  

Rules of the dynamic water-heat-salt transfer in soil of Horqin meadow during freezing and thawing period

作　　者：刘小燕[1] 刘巧玲[1] 刘廷玺[1] 段利民[1] 岳翠桐 

机构地区：[1]内蒙古农业大学水利与土木建筑工程学院,内蒙古呼和浩特010018

出　　处：《水科学进展》2015年第3期331-339,共9页Advances in Water Science

基　　金：国家自然科学基金资助项目(51169012;51139002)~~

摘　　要：为掌握科尔沁草甸地冻融期土壤水、热、盐迁移规律,以科尔沁左翼后旗阿古拉生态水文试验站2013年10月—2014年5月土壤冻融期实测气象、土壤等数据为基础,用统计分析法对研究区草甸地冻融期土壤温度、水分、盐分的变化规律进行了分析。结果表明:气温对土壤剖面温度的影响随着土壤深度的增加而降低,土壤剖面温度变化滞后于气温变化的时间取决于气温升降幅度,且没有显著的规律;由于气温回升速度大于降温速度,导致土壤消融速度比冻结速度快;土壤冻结过程由表层向下进行,冻结温度与土壤含盐量呈负相关关系,用温度的线性内插法准确确定草甸地于2014年3月9日达到最大冻深104 cm;土壤消融时受地下暖土层热流和地表温度双重影响,由底部向地表和由地表向冻结层进行双向消融;地下水位埋深较浅,受土壤冻融作用影响,升降趋势显著;草甸地土壤冻结期盐分向地表积聚,并于2月达到最大,后经消融及雨水淋润作用开始下降;冻融期盐分变异性大于水分变异性,说明盐分的运移过程更为复杂。To elucidate the dynamic water-heat-salt transfer in soil during freezing and thawing periods, data on weather and soil in Horqin meadow were analyzed and changes in the temperature, water content, and salt content of the soil in the meadow during these periods were investigated. Data were collected by the Agoura Eco-hydrological Ex- periment station at Zuoyihouqi, Horqin from October 2013 to May 2014. Results indicated that the effect of tempera- ture on the soil profile temperature decreased with increasing soil depth. In addition, changes in soil profile tempera- ture lagged behind temperature variations and were also affected by the amplitude of temperature variation. Moreover, these changes showed no significant pattern. When the rate of temperature increase exceeded that the rate of cooling, the rate of soil thawing consequently increased compared with that the rate of freezing. Freezing begins from the soil surface and proceeds deeper beneath the surface, and freezing temperature was negatively correlated with the salt con- tent of the soil. Linear interpolation of the temperature was adopted to accurately determine the maximum frost depth in the meadow on 9 March 2014. The computed maximum frost depth was 104 cm. Because of the effects of underground heat from warm soil and surface temperature, the thawing begins from two directions, namely, bottom-to-surface and surface-to-bottom. The groundwater depth is shallow and is affected by soil freezing and thawing with significant as- cending or descending trend. During the soil freezing period, soil salt accumulates on the surface and reaches the max- imum content in February. Salt content decreases after thawing and rain. During the freezing and thawing periods, the soil＇s salt content shows greater changes than soil＇s water content, thereby indicating that the salt transfer process is complicated.

关 键 词：科尔沁草甸地 冻融期 冻结温度 最大冻深 水热盐动态迁移 

分 类 号：S152.7[农业科学—土壤学] S152.8[农业科学—农业基础科学]