吉林西部典型灌区冻融期水田水盐运移特征研究

Study on the Characteristics of Water-salt Transfer during Freeze-thaw Period of Paddy Soil from the Typical Irrigation District in Western Jilin Province

冻融作用是东北干旱、寒冷地区土壤盐碱化独特的形成机制,温度的改变是导致冻融过程中土壤中水盐运移的驱动力。本文以吉林西部典型灌区大安市水田土壤为例,以冻12 h融12 h为一个循环进行室内冻融循环模拟试验,模拟初冬和初春昼融夜冻条件下的水盐运移状况。分别用质量法、电导法测定各层含水率、含盐量,研究了不同冻融条件下土壤水、盐含量的变化规律,分析了水、盐含量的相关性。研究得出:在冻融循环作用下,20—50 cm土层的水分和盐分向上层迁移,使0—20 cm土层含水率和含盐量增加,其中0—10 cm土层增加最多;0—10 cm、10—20 cm、40—50 cm土层水、盐之间具有显著的相关性。受水势梯度、冻结带、土壤结构、溶解度等因素影响,20—30 cm、30—40 cm土层水、盐之间相关性不显著;冻融过程中水分运移在一定程度上决定了盐分的运移。模拟实验结果揭示了碱盐土区冻融作用下水田土壤盐碱化的发生过程,为有效防治水田土壤盐碱化提供了基础理论依据。

Freeze-thaw action actaparticulamechanism of the formation of soil salinization in northeastern Chinwhich iarid and cold. During freeze-thaw cycle, temperature ithe driving force of water-saltransporin the soil. The experimental paddy soil wataken from Da＇ an City which ithe typical irrigation districin western Jilin Province. The freeze-thaw action wacarried ouathe indoosimulating experimenof which freeze cycle wafreezing fo12 hourand thawing fo12 hourto simulate the transporof wateand salundeday and nighfreeze-thaw conditionduring early winteand early spring. Then the soil moisture contenwatested by masmeth- od and salcontenwatested by conductivity method respectively. The variation lawof the soil moisture and salcontenare studied and analyzed the correlationof moisture and salcontenin differenfreeze-thaw conditions. The resultshow thaduring freeze-thaw cycles, the moisture and salasoil layeof 20 -50 cm transfeto the soil layeof 0 ~ 20 cm and the maximum increasing amouniathe layeof 0 -10 cm. The moisture ievidently corre- lated with the salinity athe layerof 0 ~ 10 cm, 10 ~ 20 cm and 40 - 50 cm, buaffected by factorssuch awatepotential gradient, frozen zone, soil structure and solubility, the correlation inoevidenalayerof 20 -30 cm and 30 -40 cm. To certain extent, the moisture transfedeterminethaof salt. The resulof simulating experi- mennoonly showthe formation procesof the salinization of paddy soil by freeze-thaw action in saline-alkali soil arehualso nrovidetheoretical basifonrevention and treatmenof soil salinization in studv area.