Abstract: 【Objective】To explore the improvement of saline-alkali soils by appling coal-based materials, and use the coal-based waste materials reasonably and the saline-alkali soils suitable for crop growth.【Methods】Simulated field plant-free cultivation experiments were conducted to carry out the effect of different ratios of three coal-based materials including coal slime, coal gangue and weathered coal on soil physicochemical properties such as soil bulk density, porosity, pH value, alkalinity, soluble salt content etc.【Results】Compared with the control, different ratios of coal-based materials such as coal slime, coal gangue and weathered coal could reduce the bulk density, alkalinity, pH value, soluble salt content, water-soluble anion and cation content of saline-alkali soil. Compared with the control, the pH value of the coal-based treatment was reduced by a maximum of 0.28 units, and the alkalinity was reduced by a maximum of 13.93%. The application of coal-based materials could also change the composition of soluble salts in saline-alkaline soil,increased the proportion of water-soluble SO₄^2-, Na⁺ and Cl^- and decreased the proportion of CO₃^2- and HCO₃^-.With the increase of the proportion of coal slime and the decrease of the proportion of coal gangue and weathered coal, the content of water-soluble K⁺, CO₃^2- and HCO₃^- had a downtrend, In particular, under the treatment with the largest proportion of slime (M1 Treatment). With the decrease of the proportion of coal slime and the increase of the proportion of coal gangue and weathered coal, the soil alkalinity, bulk density and porosity had a downtrend.【Conclusion】The application of different ratios of coal-based materials can improve the poor physical and chemical properties of saline-alkali soil.

Key words: Coal-based substances, Coal slime, Coal gangue, Weathered coal, Saline-alkali soil