微咸水入渗下施加石膏对盐碱土水分运动特征的影响

Effects of Gypsum on Water Movement Characteristics of Saline Alkali Soil Under Brackish Water Infiltration

基于一维垂直土柱积水入渗和水平土柱吸渗试验,研究了微咸水入渗条件下,石膏施量(0,0.1,0.2,0.4,0.6kg/m^2)对盐碱土入渗特性及水动力参数的影响。结果表明:(1)微咸水入渗条件下,施加石膏能够降低土壤入渗速率,增加土壤保水性能;随石膏施量的增大,Philip入渗模型吸渗率S逐渐减小并趋于稳定。(2)随着石膏施量的增加,饱和体积含水率增加,而饱和导水率减小,其变化均符合二项式关系。(3)van Genuchten模型参数α值随着石膏施量的增加而减小,而土壤水分特征曲线指数n值增大。(4)土壤水分扩散率随着石膏施量的增加而递减,当石膏施量>0.4kg/m^2时,土壤水分扩散率趋于稳定。施加石膏能够改善微咸水在盐碱土中的水分运动特性,提高微咸水利用率。

In this paper, water infiltration experiment were performed based on 1-dimension vertical and horizontal soil column, in order to investigate the effects of gypsum application rate （0 kg/m^2 , 0.1 kg/m^2 , 0.2 kg/m^2 , 0.4 kg/m^2 and 0.6 kg/m^2） on water movement and hydraulic parameters in saline alkali soil under brackish water infiltration. The results showed that. （1） Gypsum reduced soil infiltration rate and enhanced soil water retention capability in the soil under brackish water infiltration. With the increasing gypsum application rate, the soil sorption rate S of Philip infiltration model decreased gradually and then tended to be stable. （2） With the increasing gypsum application rate, the soil saturated water content tended to increase, while the saturated hydraulic conductivity tended to decrease, which fitted well the binomial expression. （3） The parameter a of van Genuchten model decreased with the increase of the amount of gypsum, while the soil water characteristic curve index n tended to increase. （4） The soil moisture diffusion rate decreased with the increase of the amount of gypsum, and when the amount was greater than 0.4 kg/m^2 , the soil moisture diffusion rate tended to he stable. The application of gypsum can improve the water movement characteristics o{ the brackish water and increase the utilization rate of water in the saline alkali soil.