盐分对水分蒸发和土壤裂隙发育的影响  

Effects of salts on water evaporation and soil fracture development

作　　者：冯浩轩 武廉策 邢旭光[1] 马孝义[1] 栗现文 FENG Haoxuan;WU Liance;XING Xuguang;MA Xiaoyi;LI Xianwen(Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of Ministry of Education,Northwest A&F University,Yangling,Shaanxi 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：《干旱地区农业研究》2024年第4期89-97,共9页Agricultural Research in the Arid Areas

基　　金：陕西省自然科学基础研究计划项目(2024JC-YBMS-250);国家自然科学基金(52179048,52279049,51809217)。

摘　　要：揭示盐碱土壤干燥开裂机理可为干旱半干旱盐碱地区基于裂缝网络的精量灌溉制度的制定提供理论基础。通过设置5种土壤含盐量(0、0.3%、0.6%、1%、2%,分别记作CK、T3、T6、T10、T20)处理,开展恒温土壤蒸发试验,探究含盐量对土壤蒸发过程的影响,并结合数字图像处理技术对蒸发过程中土壤干缩裂缝网络几何形态特征进行定量分析。结果表明:(1)不同处理蒸发过程具有相似性,即蒸发过程均包含一个线性阶段和一个非线性阶段,但各处理蒸发阶段占总蒸发阶段的比重不同,T20处理最早进入减速率阶段,说明盐分导致土壤渗透性减弱。(2)累积蒸发量随土壤含盐量的增加而降低,即CK>T3>T6>T10>T20,表明盐分可以抑制土壤蒸发。(3)随着土壤含盐量的增加,开裂含水量不断降低,土壤裂隙面积和长度逐渐减小随后趋于稳定。水分蒸发和表面开裂之间的相互作用表现为水分流失过程中游离Na+对土壤颗粒的化学影响和沉淀Na 2SO 4晶体对土壤孔隙的物理影响。(4)相关分析表明,累积蒸发量与土壤开裂水平呈正相关关系,含水量与土壤开裂水平呈负相关关系,且累积蒸发量与裂缝参数的相关程度整体高于土壤含水量与裂缝参数的相关程度。Revealing the drying and cracking mechanism of saline alkali soil can provide a theoretical basis for the formulation of precise irrigation systems based on crack networks in arid and semi-arid saline alkali areas.This study set up 5 types of soil salt content(0,0.3%,0.6%,1%,2%,respectively recorded as CK,T3,T6,T10,T20)treatments to conduct constant temperature soil evaporation experiments,explore the impact of salt content on soil evaporation process,and quantitatively analyze the geometric characteristics of soil shrinkage crack network during evaporation process using digital image processing technology.The results showed that:(1)The evaporation processes of different treatments had similarities,that is,the evaporation process included a linear stage and a nonlinear stage,but the proportion of each evaporation stage to the total evaporation stage was different.T20 entered the deceleration rate stage at the earliest,indicating that salt causes a decrease in soil permeability.(2)The cumulative evaporation decreased with the increase of soil salt content,namely CK>T3>T6>T10>T20,indicating that salt can inhibit soil evaporation.(3)As the soil salt content increased,the water content of the cracking decreased,and the crack area and crack length gradually decreased and then stabilization.The interaction between water evaporation and surface cracking was manifested by the chemical effects of free Na+on soil particles during water loss and the physical effects of precipitated Na 2SO 4 crystals on soil pores.(4)Correlation analysis showed that cumulative evaporation and soil moisture was significantly positively and negatively correlated with surface crack,respectively.The correlations between cumulative evaporation and crack parameters were overall higher than that between soil water content and crack parameters.

关 键 词：土壤盐分 土壤蒸发 土壤干缩裂缝 累积蒸发量 

分 类 号：S152.7[农业科学—土壤学] S152.4[农业科学—农业基础科学]