In structured soils, water and reactive solutes can move preferentially through larger inter-aggregate macropores (biopores and cracks) and smaller intra-aggregate pores. Especially clay-organic coating material is of major importance for the exchange of water and solutes between macro- and micropores and the soil matrix by affecting the reactive transport in a yet largely unknown way.

The objective of this study was to compare the adsorption and desorption behaviour of clay-organic coatings from samples of till- (T-Bt) and loess- (L-Bt) derived Bt horizons of Haplic Luvisols with those of the soil matrix and a hillslope loam-derived Bsh (HL-Bsh) horizon of a forest Cambisol-Podzol (CM-PZ) without coatings.

These coatings are characterized by q_m-values of up to 1100 μmol cm⁻³ for clay contents of up to 330 g kg^-1. The values are significantly higher than those of mixed samples without coatings (q_m of 180 μmol cm⁻³ for clay content of 115 g kg^-1). The results indicate two different adsorption mechanisms, i) sorption on siloxane surfaces of the alumosilicates (clay minerals) and ii) adsorption controlled by hydrophobic interaction with soil organic material which is possibly attached to clay-organic complexes.

The great difference in sorption properties between coatings and matrix suggests that mean values obtained from analyzing mixed samples cannot be used to describe the retardation of dissolved reactive substances on the surfaces of biopores and larger cracks during preferential flow events.

在结构化土壤中，水和反应性溶质可以优先穿过较大的聚集体间大孔（生物孔和裂缝）和较小的聚集体内孔。尤其是粘土有机涂料，通过以一种未知的方式影响反应性传输，对于大孔和微孔与土壤基质之间的水和溶质交换至关重要。

这项研究的目的是比较从Haplic Luvisols的耕种（T-Bt）和黄土-（L-Bt）衍生的Bt层样品与土壤基质和土壤中的粘土-有机涂层的吸附和解吸行为。不含涂层的森林Cambisol-Podzol（CM-PZ）的山坡壤土衍生的Bsh（HL-Bsh）层位。

这些涂料的特征在于，对于粘土含量最高为330 g kg ^-1的q _m值最高为1100μmolcm ^-3。该值显着高于没有涂层的混合样品（粘土含量为115 g kg ^-1的q _m为180μmolcm ^-3）。结果表明两种不同的吸附机理，,）在铝硅酸盐（粘土矿物）的硅氧烷表面上的吸附和）通过与土壤有机物的疏水相互作用控制的吸附，土壤有机物可能附着在粘土-有机络合物上。

涂层和基质之间的吸附性能差异很大，这表明通过分析混合样品获得的平均值不能用于描述优先流动事件中生物孔表面溶解的反应性物质和较大裂纹的延迟。