亚热带土壤导水特征对钠盐溶液浓度的响应  

Response of soil hydraulic property to sodium salt solution concentration in subtropical zone

作　　者：胡传旺[1] 王辉[1] 卢佳宇 谭帅 武芸[1] Hu Chuanwang;Wang Hui;Lu Jiayu;Tan Shuai;Wu Yun(College of Water Resources and Civil Engineering,Hunan Agricultural University,Changsha 410128,China)

机构地区：[1]湖南农业大学水利与土木工程学院,长沙410128

出　　处：《农业工程学报》2020年第3期86-91,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(41471185);湖南省水利科技项目重大项目(湘水科计[2017]230-240);湖南省重点研发计划项目(2016JC2032);湖南省研究生科研创新项目(CX2017B363)。

摘　　要：再生水中高浓度钠盐溶液入渗对土壤水力特性的影响是长期低质水灌溉引起土壤生态环境退化的关键问题之一。该文采用定水头渗透法、一维水平土柱吸渗法测定不同浓度钠盐溶液条件下亚热带地区黏性潮土、沙性潮土、红壤、水稻土、紫色土共5种土壤的水动力学参数,分析了土壤理化性质和钠盐溶液浓度对土壤导水特征的影响及其作用机制。结果表明:土壤粉粒、交换性钙及交换性镁含量具有促进土壤水分运动的作用,而土壤黏粒、交换性铁及交换性铝含量则表现出抑制作用。与蒸馏水处理相比较,钠盐加快了土壤水分黏性潮土、沙性潮土及水稻土中的土壤水分运动速率,分别可最高提升其土壤水分扩散率为22.0%、37.3%、39.7%;钠盐减缓了红壤和紫色土的水分扩散速率,溶液钠盐浓度越高,其抑制作用越明显。土壤饱和导水率随溶液盐浓度升高呈先降后升的趋势,1~10 g/L钠盐浓度范围内土壤饱和导水率与钠盐浓度具有良好的抛物线关系(R^2>0.807),各土壤导水率最小极值点的钠盐浓度在5 g/L左右。因此,再生水灌溉利用时其盐浓度适度控制低于其极值点浓度。The effect of high concentration sodium salt solution infiltration in reclaimed water on soil hydraulic characteristics is one of the key problems of soil ecological environment degradation caused by long-term low-quality water irrigation.In this paper,the hydrodynamic parameters of 5 kinds of subtropical soil,such as clay fluvo aquic soil,sandy fluvo aquic soil,red soil,paddy soil and purple soil,were measured by constant head penetration method and one-dimensional horizontal soil column imbibition method.The influence of sodium salt solution concentration on the hydraulic properties of soil was investigated,and the mechanism of the physical and chemical properties of soil affecting the hydraulic conductivity was analyzed.The results showed sodium slat solution infiltration could enhance soil wet front migration rate of clay fluvo aquic soil,sandy fluvo aquic soil and paddy soil maximally by 33.0%,32.5% and 93.5%,lower that of red soil maximally by 34.8%.The soil clay content,exchangeable iron and aluminum content mainly inhibited soil water movement,while silt content,exchangeable calcium and magnesium content promoted soil water movement.Sodium salt accelerated water movement in clay fluvo aquic soil,sandy fluvo aquic soil and paddy soil.Relative soil water diffusivity increased by 22.0%,37.3% and 39.7% respectively.Sodium salt inhibited the water diffusion of red soil and purple soil.The higher salt concentration could result in the smaller relative soil water diffusivity.At 15 g/L salt concentration,the soil water diffusivity decreased by 30.5%for red soil and 42.1%for purple soil,respectively.Relative soil water diffusivity of clay fluvo aquic soil,sandy fluvo aquic soil,red soil and purple soil fluctuated with the increase of soil water content,while the relative soil water diffusivity of paddy soil decreased with the increase of soil water content.Relative soil water diffusivity of paddy soils showed a good parabolic relationship with salt concentration(R^2=0.987),while red soils and purple soils showed a

关 键 词：土壤 水分 钠盐溶液 相对湿润锋运移速率 相对土壤水分扩散率 相对饱和导水率 

分 类 号：S152.7[农业科学—土壤学]