Soil water repellency is phenomenon which is caused by compounds of organic origin, type of clay minerals and wetting/drying cycles. Hydrophobicity is usually characterized by a great spatial and temporal variability, especially in mine spoils where different types of overburden materials are mixed with coal particles and other waste products. The aim of this study was to investigate the changes of hydrophobicity with soil moisture content of Heavy Clay textured Spolic Technosols in the region of Maritsa-Iztok open cast coal mine. The sampling was done in a stubble field at 8 points from two soil depths 10–15 cm and 30–35 cm. The samples were analyzed for particle size distribution, total organic carbon content, soil bulk density, soil moisture content at field sampling, soil particle density, soil moisture content and water-drop-penetration-time (WDPT) at different matric potentials (SWRCC). The irregular presence of coal particles and different overburden sediments lead to spatial variability of studied properties, especially of total organic carbon content. In depth the average clay content, organic carbon content, water retention properties and soil water repellency (SWR) increased and correspondingly the density properties decreased. The distribution of SWR classes of the studied samples at the applied suctions during the drying process showed that the hydrophilicity of all samples at saturation persisted at suction pF 1.0 in 73% of the samples Most of the samples at suctions pF 1.7 and pF 2.0 were with slight and strong water repellency, but still there were hydrophilic samples 27% and 18%, correspondingly. At pF 2.5, which is often accepted as field capacity of fine textured soils, all samples were water repellent. The further drainage of the samples at pF >3.3 led to domination of extreme SWR and above pF3.7 all samples were extremely water repellent. Besides the unfavorable consequences of water repellency, the dry hydrophobic topsoil at the time of sampling formed a capillary barrier that reduced the evaporation and led to nearly 3 times higher water content stored in the subsoil.

土壤拒水性是由有机化合物、粘土矿物类型和润湿/干燥循环引起的现象。疏水性通常具有很大的空间和时间可变性，特别是在矿渣中，不同类型的覆盖层材料与煤颗粒和其他废物混合。本研究的目的是研究 Maritsa-Iztok 露天煤矿地区重粘土纹理 Spolic Technosols 的疏水性随土壤水分含量的变化。采样是在留茬地中从两个土壤深度 10-15 厘米和 30-35 厘米的 8 个点进行的。分析样品的粒度分布、总有机碳含量、土壤容重、田间取样时的土壤含水量、土壤颗粒密度、不同基质势 (SWRCC) 下的土壤水分含量和水滴渗透时间 (WDPT)。煤颗粒和不同覆盖层沉积物的不规则存在导致所研究性质的空间变异性，尤其是总有机碳含量。在深度上，平均粘土含量、有机碳含量、保水性能和土壤拒水性 (SWR) 增加，相应地密度性能下降。在干燥过程中施加的吸力处研究样品的 SWR 等级分布表明，所有样品在饱和吸力 pF 1.0 下的亲水性在 73% 的样品中持续存在 大多数吸力 pF 1.7 和 pF 2.0 的样品具有疏水性略强，但仍有相应的亲水样品27%和18%。在 pF 2.5 时，这通常被认为是细质地土壤的田间容量，所有样品都是防水的。pF > 3.3 的样品进一步排水导致极端 SWR 占主导地位，pF3.7 以上的所有样品都具有极强的防水性。除了防水性的不利后果外，采样时干燥的疏水表土形成了毛细管屏障，减少了蒸发，导致底土中储存的含水量增加了近 3 倍。