The analysis of solute transport characteristics in soil is of great significance in understanding nutrient cycling and pollutant migration in the Earth’s Critical Zone. The objective of this study was to investigate the transport characteristics and the influencing factors of Cl⁻ in soils with different textures (sandy-S and loamy-L), and covered by different vegetation types (arbor-AR, shrub-SH and grass-GR) in the water–wind erosion crisscross region of the northern Loess Plateau of China. Results showed that the initial penetration time (TS: 12–80 min), entire penetration time (TE: 75–480 min), average flow velocity in the pore (V: 0.52–1.98 cm h⁻¹) and the hydrodynamic diffusion coefficient (D: 0.75–2.55 cm² h⁻¹) of Cl⁻ varied with different soil textures and vegetation types, and at different soil depths. The V and D associated with Cl⁻ transport were highest in the 0–20 cm soil layer and decreased with increasing depth, while the opposite trend was observed for TS and TE. For the 0–1 m soil profile of the same texture but covered by different vegetation types, the average V and D followed the order of S-AR > S-GR > S-SH and L-AR > L-SH > L-GR, while the average TS and TE exhibited the exact opposite order. This behavior is caused by the varying distributions of root biomass under different vegetation types that affect the number of macropores, the connectivity density and the preferential flow paths in the soil. For the 0–1 m soil profiles of different textures covered by the same vegetation type, the average V and D followed the order of S-AR > L-AR; S-SH > L-SH; and S-GR > L-GR, while the average TS and TE showed the opposite trend. This is because the pore size and distribution in soil are significantly affected by soil mechanical composition. There are significant correlations between soil properties (e.g., bulk density, number of macropores, pore connectivity density, saturated hydraulic conductivity, soil organic carbon content and particle composition) and the transport parameters (e.g., V, TS, and TE). The pedotransfer functions using readily available soil properties can adequately predict V of Cl⁻ transport under different conditions of soil texture and vegetation type. These results provide guidance for the rational configuration of artificial vegetation in different textural soils with respect to reduce nutrient loss and improve ecosystem functions in the northern Loess Plateau of China.

分析土壤中的溶质运移特性对理解地球关键区的养分循环和污染物迁移具有重要意义。本研究的目的是研究Cl-在不同质地（桑迪-S和壤土-L）且覆盖有不同植被类型（乔木-AR，灌木-SH和草^-土壤）的土壤中的迁移特征及其影响因素。黄土高原水风侵蚀纵横交错的地区。结果表明，初始渗透时间（TS：12–80分钟），整个渗透时间（TE：75–480分钟），孔中平均流速（V：0.52–1.98 cm h ^-1）和流体动力扩散系数（D：0.75–2.55 cm ² ħ ^-1的Cl）^-变化具有不同土壤质地和植被的类型，并且在不同的土壤深度。的V和d被Cl相关联^-运输分别在0-20厘米土壤层最高和随深度增加而降低，而观察到的TS和TE相反的趋势。对于相同质地但被不同植被类型覆盖的0-1m土壤剖面，平均V和D遵循S-AR> S-GR> S-SH和L-AR> L-SH> L-GR的顺序，而平均TS和TE呈现完全相反的顺序。此行为是由于根系生物量在不同植被类型下的变化分布而引起的，这些分布影响土壤中大孔的数量，连通性密度和优先流动路径。对于相同植被类型覆盖的不同质地的0-1m土壤剖面，平均V和D遵循S-AR> L-AR的顺序；S-SH> L-SH; S-GR> L-GR，而平均TS和TE则呈现相反的趋势。这是因为土壤的孔径和分布受土壤机械组成的影响很大。土壤性质（例如，堆密度，大孔数，孔隙连通性密度，饱和导水率，土壤有机碳含量和颗粒组成）与运输参数（例如，V，TS和TE）之间存在显着相关性。使用容易获得的土壤性质的pedotransfer功能可以充分预测V的Cl ^-土壤质地和植被类型在不同条件下的运输 这些结果为在黄土高原北部减少土壤养分流失和改善生态系统功能方面合理配置不同质地土壤的人工林提供了指导。