【摘要】 溶质弥散是评价和预测土壤和地下水迁移的关键物理参数，然而，在较高的实时和原位测量中，没有全面、严格地评价水通量（J_w）和土壤质地对溶质分散的影响。该研究以Cl^-为示踪剂，定量分析饱和充填砂土、粉壤土和砂质粘壤土的溶质分散特征。采用反演模型，通过将溶质输运模型拟合到时域反射技术测量的溶质穿透曲线中，导出溶质弥散系数（D）。结果表明：J_w为3.2×10^-6～6.0×10^-5 m/s, D与土壤质地和J_w密切相关。随着J_w的增加和土壤质地的变细，D呈非线性增加。这可以用D和J_w之间的幂函数来描述。弥散度几乎保持不变，砂质粘壤土的弥散度约为砂土的5.3倍，粉质壤土的2.5倍。研究结果进一步证明，弥散度主要由土壤质地决定，这将有助于评估和预测污染物和养分在土壤和地下水中的迁移。更多还原

【Abstract】 Solute dispersion is a key physical parameter for evaluating and predicting soil and groundwater migration. However, the influence of water flux（J_w） and soil textures on solute dispersion has not been comprehensively and rigorously evaluated in real-time and in-situ measurements. In this study, Cl^- was used as a tracer to quantitatively analyze the solute dispersion characteristics of saturated packed sand, silt loam, and sandy clay loam soils. An inverse model was employed to derive solute dispersion coefficient（D） by fitting the solute transport model to the solute breakthrough curves measured using the time-domain reflectometry technique. Results indicated that J_w ranged from 3.2×10^-6～6.0×10^-5 m/s, and D was closely related to soil textures and J_w. With J_w increased and soil texture became finer, D increased in nonlinear, which could be described by a power function between D and J_w. Dispersivity remained almost constant with J_w changed. The dispersivity in sandy clay loam was approximately 5.3 times and 2.5 times higher than that of sand and silt loam, respectively. The findings further proved that dispersivity was determined mainly by soil textures, which would assist in assessing and predicting the transport of pollutants and nutrients in soil and groundwater.更多还原