In structured soils, clay-organic coatings are spatially distributed along macropore surfaces. Information on thickness and volume of coating material is essential for macropore-matrix mass exchange of water and solutes. However, their determination is difficult and fraught with uncertainty due to irregular shapes of macropore surfaces. The objective of this study was to test the use of a three-dimensional (3D) confocal laser scanning microscope for gauging soil macropore coatings. For this test, coating material was manually separated from the surface of intact soil clods (5 cm edge length) sampled from Bt horizons (with illuvial clay) of till-derived and loess-derived Haplic Luvisols. The resulting coating thicknesses ranged between approx. 0.1 and 0.5 mm and volumes between 0.057 and 2.9 mm³ with mean densities of 1.96 g cm⁻³ for loess-derived and 2.67 g cm⁻³ for till-derived coatings. The 3D laser microscopic method yielded data based on micro-topographic information. The key benefits of the 3D confocal laser scanning microscope are the information on the mm-scale spatial distribution of coating thickness and bulk density. These additional parameters of the clod surface or aggregate micro-topography can be useful for improved quantification of accessibility of sorption surfaces and for describing macropore-matrix mass transfer of reactive solutes.

在结构化土壤中，粘土有机涂层沿大孔表面在空间上分布。涂层材料的厚度和体积的信息对于水和溶质的大孔基质质量交换至关重要。然而，由于大孔表面的不规则形状，它们的确定是困难的并且充满不确定性。这项研究的目的是测试使用三维（3D）共聚焦激光扫描显微镜对土壤大孔涂层进行测量。对于该测试，将涂层材料从完整的土块表面（5 cm边缘长度）上分离，该土块样品取自Bt层（含耕层土）的Bt层（含土黄土）Haplic Luvisols。所得的涂层厚度在约1-10mm之间。0.1至0.5 mm，体积在0.057至2.9 mm ^3之间黄土衍生涂层的平均密度为1.96 g cm ^-3，耕作衍生涂层的平均密度为2.67 g cm ^-3。3D激光显微镜方法基于微形貌信息生成数据。3D共聚焦激光扫描显微镜的主要优点是涂层厚度和堆积密度的毫米级空间分布信息。凝块表面或聚集体微形貌的这些附加参数可用于改进对吸附表面可及性的定量，并用于描述反应性溶质的大孔-基质传质。