Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater.

中文翻译：

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在灌溉中使用废水：对粘土中渗透过程的影响

土壤水分渗透是土壤水循环和农业实践中的一个关键过程，尤其是当废水用于灌溉时。尽管已经进行了研究以评估处理过的废水灌溉的土壤的物理和化学特性的变化，但仍然缺乏对渗透过程产生的影响的定量分析。本研究的目的就是解决这个问题。以前在三个相邻的田间地块上进行的田间试验以相同的粘质土壤为特征，​​但已经使用了三种不同的灌溉处理。三种灌溉条件为：非灌溉（自然条件）地块、处理废水两年的灌溉地块和处理废水五年的灌溉地块。由 Hood 渗透计执行的渗透测量已用于估计土壤水力特性，可用于校准在灌溉阶段存在的积水条件下广泛使用的简化渗透模型。我们的模拟强调了废水作为灌溉源在减少累积渗透和增加地表流量方面的相关影响，这是由于以较低的排水能力为特征的土壤水力特性的改变。这些结果可以为在干旱地区优化灌溉技术提供重要见解，在这些地区，由于淡水长期短缺，经常需要使用废水。