Abstract:In order to understand the effect of coal accumulation on soil structure, three different levels of coal accumulation soils samples (low accumulation, moderate accumulation and high accumulation) were collected from the Jiaozuo mine-crop overlapped zone, and the coal-free soil was taken as the control. Soil samples were collected in the 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm soil layers. Water-stable aggregate fractions were measured, and fractal dimension (D), mean weight diameter (MWD), geometric mean diameter (GMD) and macroaggregate destruction rate (PAD) were used as evaluation indicators to evaluate the effects of coal on the composition and stability of soil aggregates. The results showed that coal accumulation in the soils promoted the transformation of soil water stable microaggregates to macroaggregates, reduced the D value and increased soil aggregate stability. The increase amplitude of water stable macroaggregate content in deep soil layer (20-40 cm) was higher than that in surface soil layer (0-20 cm). Soil aggregate stability showed a trend of increase firstly and then decrease with the increasing of coal accumulation. It was also found that soil aggregate stability depended mainly on the content of water stable aggregates that greater than 2 mm. Our results suggested that coal accumulation in soils obviously improved soil structure. In addition, according to the results of this study, the "black soils" phenomenon due to long-term transportation, dumpling and washing of coal and mine water drainage and irrigation in the study area should not be considered as coal pollution.