In this study, a tracer field experiment was conducted to study the temporal dynamics of bromide movement in a loamy tile-drained agricultural landscape. Moreover, tritium leaching experiments were performed on undisturbed soil columns from the same field. The HYDRUS-2D software package was used to model water and solute transport. Three water flow models developed in Part 1—a single-porosity approach with modified soil hydraulic functions (SP), a dual-porosity approach (DP), and a dual-permeability approach (DUP)—were used as a foundation for building solute transport models, of which the initial parameterization was based on a suggested hydrogeological tool from previous studies. The selected solute transport models were an SP, an SP with immobile water, a DP, a DUP, and a DUP with immobile water. The model predictions were compared against measurements of bromide concentrations in soil-water. The DP captured the degree of the initial peaks and predicted well the shape of the observed concentrations. However, DP presented low capability to match the timing of bromide concentration peaks. In contrast, the DUP with immobile water illustrated better predictive ability by introducing an additional pore region into the matrix domain. Validation of field-scale solute transport models was implemented using the data from the following leaching experiments. The already suggested parameterization concept was further evaluated for its capability to provide a sufficient initial representation of the internal pathways. The output from such hydrogeological studies shows that macropores and their interconnection with tile drains are key to understanding the water flow and solute transport processes in loamy structured soils.

中文翻译：

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HYDRUS-2D 中二维方法的参数化：第 2 部分。场和柱尺度的溶质输运

在这项研究中，进行了示踪剂田间试验以研究溴化物运动在壤土排水的农业景观中的时间动态。此外，氚浸出实验是在来自同一领域的未受干扰的土柱上进行的。HYDRUS-2D 软件包用于模拟水和溶质运移。第 1 部分中开发的三种水流模型 — 具有修正土壤水力函数 (SP) 的单孔隙率方法、双孔隙率法 (DP) 和双渗透率法 (DUP) — 被用作构建溶质的基础传输模型，其中初始参数化基于先前研究中建议的水文地质工具。选定的溶质运移模型是 SP、具有固定水的 SP、DP、DUP 和具有固定水的 DUP。将模型预测与土壤-水中溴化物浓度的测量值进行比较。DP 捕获了初始峰的程度并很好地预测了观察到的浓度的形状。然而，DP 表现出匹配溴化物浓度峰值时间的低能力。相比之下，具有固定水的 DUP 通过在基质域中引入额外的孔隙区域，显示出更好的预测能力。使用来自以下浸出实验的数据实施了现场规模溶质迁移模型的验证。已经建议的参数化概念进一步评估了其提供内部通路的充分初始表示的能力。