中文摘要：

用通过稀释方法获得不同pH值的硫酸溶液来模拟南方硫酸型酸雨,利用水平土柱吸渗法测定非饱和土壤水分扩散度,渗透筒法测定土壤饱和导水率,探讨了不同浓度酸性溶液渗透红壤过程中土壤水分入渗特征变化;利用RETC软件拟合不同酸性溶液入渗下红壤的扩散度和水分特征曲线,并与实测的扩散度值进行对比与分析。研究结果表明：不同酸性溶液入渗时,红壤入渗速率、水分扩散度和饱和导水率的大小关系均为（pH=3）〉（pH=5）〉蒸馏水〉（pH=2）〉（pH=1）;RETC软件拟合扩散度与实测值吻合度较高,其剩余标准差均接近0;pH=1溶液使土壤持水能力增强,而pH=5,pH=3,pH=2溶液使土壤持水能力减弱。在硫酸型弱酸溶液（pH≥3）作用下红壤水分入渗能力呈增大趋势,土壤持水能力降低;而当酸性溶液pH〈3时,红壤入渗能力、持水能力则反之。

英文摘要：

Effects of acid solution on the hydraulic characteristics of red soil was investigated by using dilute sulfuric acid to simulate acid rain in southern region of China.And using one horizontal soil column and absorption method to measure unsaturated soil diffusivity and penetration tube of vertical infiltration method to measure saturated hydraulic conductivity,this paper discussed the red soil infiltration characteristics under different concentration of acid solution.Soil diffusivity and moisture characteristic curve under different acid solution infiltration was fitted by RETC software and compared fitted soil diffusivity with measured values.The results showed that the infiltration rate,diffusivity and saturated hydraulic conductivity of red soil differed with applied solutions in the terms of pH by the order of 3〉5〉7（distilled water）〉2〉1;diffusivity fitted by RETC software highly coincided with measured values and the residual standard deviations were close to zero.Acid solution with pH=1enhanced soil water retention capacity,while acid solution with pH=5,pH=3,pH=2reduced the soil water retention capacity.It suggested that under the action of weak acid solution（pH≥3）,it showed a trend of increase in water infiltration capacity for red soil and reduce in soil water-holding capacity,and when acid solution pH was less than 3,the results were opposite.