Wastewater has been widely reclaimed to irrigate crops where freshwater resources are scarce. Therefore, predicting the impacts of wastewater irrigation on soil moisture and soil salinity is critical for sustainable wastewater irrigation management. In this study, the denitrification-decomposition (DNDC) model was modified to couple wastewater irrigation with a water balance equation (SALT-DNDC). Secondly, the SALT-DNDC model was verified against the measured soil moisture, temperature, and nitrous oxide emission during the barley-growing season at Lethbridge, Alberta, Canada. Third, the SALT-DNDC model was used to predict the effects of one-time and split wastewater irrigation with varying quantity and quality on transpiration and soil salinity. The results showed that split irrigation of wastewater with an electrical conductivity of 6 dS m⁻¹ reduced the peak soil salinity from 52–55 dS m⁻¹ to a range of 8–20 dS m⁻¹, compared to one-time irrigation. Therefore, the split irrigation of wastewater could substantially reduce peak soil salinity. In this regard, optimal split wastewater irrigation with elevated salt concentration can limit soil salinity to acceptable salt tolerance levels for crop growth. The SALT-DNDC model can simulate dynamics of split irrigation wastewater and offers a new tool for assessing the effects of wastewater reuse on soil salinity.

中文翻译：

---

使用 SALT-DNDC 模型模拟废水灌溉对土壤盐度的影响

在淡水资源稀缺的地方，废水已被广泛回收用于灌溉农作物。因此，预测废水灌溉对土壤水分和土壤盐度的影响对于可持续废水灌溉管理至关重要。在这项研究中，反硝化分解 (DNDC) 模型被修改为将废水灌溉与水平衡方程 (SALT-DNDC) 耦合。其次，根据在加拿大艾伯塔省莱斯布里奇的大麦生长季节测量的土壤湿度、温度和一氧化二氮排放量对 SALT-DNDC 模型进行了验证。第三，SALT-DNDC模型用于预测不同数量和质量的一次性和分流废水灌溉对蒸腾作用和土壤盐分的影响。结果表明，电导率为6 dS m的废水分流灌溉与一次性灌溉相比，^-1将峰值土壤盐度从 52-55 dS m ^{-1 降低}到 8-20 dS m ^-1的范围。因此，污水分灌可以显着降低土壤盐分峰值。在这方面，提高盐浓度的最佳分流废水灌溉可以将土壤盐度限制在作物生长可接受的耐盐水平。SALT-DNDC 模型可以模拟分流灌溉废水的动态，并为评估废水回用对土壤盐分的影响提供了一种新工具。