Effect of coal gasification coarse slag on soil water and nutrition at an arid opencast coal mine site in Northwest China

Though amendment using coal gasification coarse slag (CGCS) has garnered attention, the intrinsic mechanism of how CGCS, a glassy material, works to amend physicochemical properties in the soil is not yet clear. This study aimed to analyze the effects of different CGCS particle sizes on soil water infiltration and nutrient retention, and to identify the relationship between the physicochemical properties of the amended soil and the water nutrient amendment. The continuous infiltration pattern of soil water and plant growth after the amendment was measured using an indoor continuous dynamic soil column simulation experiment and a field pot experiment of CGCS with different particle sizes (0.25, 1, and 2 mm). The CGCS amendment loosened the soil, improved the pore channels, and amended the water infiltration. However, this process was negatively correlated with CGCS particle size. The Kostiakov performed better in simulating soil water infiltration of heterogeneous dump soil. The CGCS amendment had no heavy metal risk and promoted plant growth. Though amendment enhanced nutrients, in terms of soil organic matter (SOM), the presence of C must be verified by a long team of nutrient cycling if it can be transformed into accessible SOM. Therefore, CGCS amended water nutrition by amending the soil's physical structure. Soil pore adsorption improved water nutrient availability and had a positive effect on chemical properties, which promoted crop growth. The amendment effect was greatest at 0.25 mm particle size.