In Tunisia, water used for irrigation is often saline, increasing the risk of salinization for soils and crops. In this study, an experiment was conducted on a tomato crop cultivated on a silty-clay soil irrigated with three different water qualities: 0, 3.5, and 7 dS·m−1. Experimental data were then used to calibrate and validate the Hydrus-1D model, which simulates water flow and salt transfer in soils. The successfully-calibrated and validated model was then used to study the combined effects of the soil osmotic and soil matrix potentials on root water uptake. The values of the root mean square error (RMSE), the coefficient of determination (CD), the modeling efficiency (EF), and the coefficient of residual mass (CRM) were close to their optimal values for both soil water content and soil electrical conductivity profiles, indicating the reliability of the model to reproduce water and salt dynamics. Relative yields (Yr), indirectly estimated using actual and potential root water uptake (transpiration), indicated that the multiplicative stress response model (using the S-shape model) satisfactorily simulates measured yields and reproduces the effects of irrigation with saline waters on crop yields. An alternative scenario using a reduction of water requirements by 50% was investigated to assess an irrigation method with considerable water savings. As the results show that relative yields, Yr, were only slightly reduced, the crop water requirements estimated by CROPWAT 8.0 must have been overestimated. The variation of the soil salinity in the root zone highlighted a high salinization risk in the short-term when water of 7 dS·m−1 is used for irrigation.

中文翻译：

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突尼斯半干旱地区土壤剖面中水盐动态的模拟——对番茄作物灌溉方法的评价

在突尼斯，灌溉用水通常是含盐的，增加了土壤和作物盐渍化的风险。在这项研究中，对种植在粉质粘土土壤上的番茄作物进行了一项试验，该土壤用三种不同的水质灌溉：0、3.5 和 7 dS·m-1。然后使用实验数据校准和验证 Hydrus-1D 模型，该模型模拟土壤中的水流和盐分转移。然后使用成功校准和验证的模型来研究土壤渗透势和土壤基质势对根系吸水量的综合影响。均方根误差 (RMSE)、决定系数 (CD)、建模效率 (EF) 和残余质量系数 (CRM) 的值均接近其土壤含水量和土壤电的最佳值。电导率曲线，表明该模型重现水和盐动力学的可靠性。相对产量 (Yr)，使用实际和潜在的根系吸水量（蒸腾作用）间接估计，表明乘法应激反应模型（使用 S 形模型）令人满意地模拟了测量的产量并再现了用盐水灌溉对作物产量的影响. 研究了一种将需水量减少 50% 的替代方案，以评估一种节水效果显着的灌溉方法。由于结果显示相对产量 Yr 仅略微降低，因此 CROPWAT 8.0 估计的作物需水量肯定被高估了。根区土壤盐分的变化突显了当灌溉用水为7 dS·m-1时，短期内存在较高的盐渍化风险。