油脂对红壤结构性质与水流运动特征的影响

本文通过室内灌水入渗试验，研究了灌溉水油脂浓度（0，1.0，3.0和10.0g/L）、灌水频率（1d1次，2d1次，4d1次）和灌溉模式（纯清水灌溉，纯含油脂灌溉水灌溉，含油脂灌溉水-清水交替灌溉）对受灌土壤结构性质与水流运动特征的影响.结果显示，随灌水进入到受灌土壤中的油脂主要集中在优先流通道中快速运动，优先流湿润锋处的土壤油脂浓度较高且不受灌溉水中油脂浓度的影响，表明即便是采用较低油脂浓度的灌溉水灌溉，依然对地下水系统存在较高的污染风险；高频率、低定额的含油脂灌溉水灌溉有利于进入到受灌土壤中的油脂向深层土壤运动，使得斥水性土层厚度增大，从而导致入渗水流运动的不确定性及地下水系统的污染风险均增大；油脂对受灌土壤团聚体的再团聚作用只有在其浓度较高时才能形成，含油脂灌溉水-清水交替灌溉因降低了受灌土壤的油脂浓度反而导致土壤团聚体分散和破碎.研究成果对再生水和原污水农田灌溉制度设计具有参考价值.

Effects of oil in irrigation water on structural properties and water flow characteristics of red soil

Laboratory irrigation experiments carried on manually filled soil columns were conducted to study the effects of oil concentration in irrigation water (i.e. 0, 1.0, 3.0and 10.0g/L), irrigation frequency (irrigated every day, once every two days, and once every four days), and oil laden water and freshwater alternative irrigation schedule (irrigated with freshwater only, with oil laden water only, and with oil laden water and freshwater alternatively) on soil structural properties and water flow characteristics. The results showed that, the applied oil was mainly entrapped in the preferential flow paths, making the preferential wetting front with high oil concentration which was not obviously affected by the oil concentration in irrigated water, illustrating that irrigation with low oil concentration water also present groundwater system under high contamination risk; higher irrigation frequency with lower irrigation quota led to more applied oil being transmitted to deeper soil layer, increasing the thickness of water repellent soil layer, and deriving the uncertainty of infiltrated water flow and the contamination risk of groundwater system both increased; the re-aggregation feature of oil on soil aggregates was only activated under high soil oil concentration, and the alternative irrigation with oil laden water and freshwater reduced the soil oil concentration, inducing the dispersion of soil aggregates. This research had certain reference value for reclaimed water and raw sewage irrigation scheduling design.