再生水中阴离子表面活性剂对土壤结构与水流运动的影响

为揭示再生水回灌农田所引入的阴离子表面活性剂对土壤结构性质与水流运动特征的影响，通过室内灌水入渗试验研究了再生水中阴离子表面活性剂浓度（0、0.001、0.01和0.1倍临界胶束浓度）、灌水频率（1d1次、2d1次、3d1次）、再生水-清水交替灌溉模式（纯再生水灌溉、再生水-清水交替灌溉）条件下受灌土壤容重、非毛管孔隙比、团聚体稳定性、土壤斥水性、地表入渗性能和入渗水流运动非均匀特征的变化规律.结果表明，随着再生水中的阴离子表面活性剂浓度的增大和灌溉频率的增大，受灌土壤容重减小、非毛管孔隙比和土壤团聚体稳定性增大、土壤斥水性增强、地表入渗能力降低、优先流运动非均匀程度增大，从而也增大了农田灌水管理难度；当再生水-清水交替灌溉中的清水淋洗频率增大时，受灌土壤容重增大、非毛管孔隙比和土壤团聚体稳定性降低，但却降低了土壤的斥水性、增大了地表入渗能力并降低了土壤优先流运动的非均匀程度，有利于节省灌水时间、提高灌水效率.

Effects of anionic surfactant in reclaimed water on soil structural properties and water flow characteristics

Irrigation experiments with three different irrigation conditions, i.e. different concentration of anionic surfactant in irrigation water (i.e. 0critical micelle concentration (CMC), 0.001CMC, 0.01CMC and 0.1CMC), irrigation frequencies (irrigated every day, once every two days, and once every three days), and reclaimed water and freshwater alternative irrigation schedules (irrigated with reclaimed water only, and irrigated with reclaimed water and freshwater alternatively) were conducted in laboratory with man-filled soil columns to study the effects of surfactant in reclaimed water on soil bulk density, porosity structure, aggregate stability, soil water repellency, surface infiltrability and preferential flow heterogeneity. Higher concentration of anionic surfactant in reclaimed water and higher irrigation frequency with lower irrigation quota both lead to smaller soil bulk density, greater non-capillary porosity ratio and normalized mean weight diameter of soil aggregate, higher soil water repellency, worse surface infiltrability, and stronger preferential flow behavior, which increased the difficulty of farmland management; higher frequency of freshwater flush in reclaimed water and freshwater alternative irrigation increased soil bulk density, decreased non-capillary porosity ratio and normalized mean weight diameter of soil aggregate, reduced soil water repellency, enhancing surface infiltrability, and decreased preferential flow heterogeneity, which decreased the time for farmland irrigation and increased irrigation efficiency.