Analysis of differences in chemical properties of reconstructed soil under different proportions of topsoil substitute materials.

Abstract

The purpose of this study was to evaluate the soil substitutes in land reclamation following mining activities. This study revealed different reconstructed soil materials have different effects on the chemical properties of reconstructed soil and explored the appropriate proportions of reconstructed soil materials. Using topsoil, coal gangue, fly ash, and rock and soil stripping material from the Shengli Mining Area of Inner Mongolia in China as raw materials, potting experiments were carried out according to different proportions. The variance analysis method was used to analyze the difference in the soil pH values, soil organic matter (SOM) content, soil total nitrogen (STN) content, soil available phosphorus (SAP) content and soil available potassium (SAK) content of the reconstructed soil, and the reasons for the difference were discussed. The results showed that in the treatment group where the topsoil substitute material was coal gangue, when the coal gangue content was 30%, 40%, and 50%, the pH values of reconstructed soil were lower than that of the control scheme. When the coal gangue content exceeded 10%, the soil nutrient status was obviously improved. In the treatment group where the topsoil substitute material was fly ash, the chemical properties of reconstructed soil tended to deteriorate. In the treatment group where the topsoil substitute material was rock and soil stripping material, when the content of rock and soil stripping material exceeded 20%, the chemical properties of reconstructed soil were mostly better than those of the control scheme. The study of the different proportions of coal gangue, fly ash, and rock and soil stripping material as topsoil substitute materials provide support for reclamation work in mining areas where topsoil is scarce, as well as a reference for ecological restoration projects in grassland open-pit mining areas around the world.