Optimization of Improved Substrates on Soil Physical and Chemical Properties in Coal Mining Areas
The massive exploitation of coal resources has caused serious damage to land resources,in order to improve the soil in the mining area,in this study,the soil in a coal mining area in Yulin city was used as a sample,and a total of 13 treat-ments were set up,such as blank control(CK1),5%of coal gasification slag(CK2),5%of coal gasification slag and spent mush-room substrate,5%of coal gasification slag and corn straw biochar,and 5%coal gasification slag+spent mushroom substrate+corn straw biochar.The physical and chemical properties of the treated soil were measured.The improvement effect was comprehensively evaluated by principal component analysis,and the effective soil improvement formula in mining areas was se-lected.The results showed that compared with CK1,the capillary water capacity,porosity,pH,and alkali-hydrolyzable nitro-gen of the soil treated with CK2 increased by 12.32%,0.92%,21.41%,and 12.89%,respectively,and the organic matter,available phosphorus,available potassium,and salt content significant decreased by 76.52%,39.56%,26.85%,and 25.12%,respectively.Compared with the CK2 treatment,the combined application of 5%of coal gasification residue and spent mush-room substrate,5%of coal gasification residue and corn straw biochar,and the combined application of 5%of coal gasification residue+spent mushroom substrate+corn straw biochar could all effectively improved the physical and chemical properties of soil.Among them,compared with the CK2 treatment,after applying 5%of coal gasification residue+30%of spent mush-room residue+10%of biochar to the soil in the mining area,the soil bulk density,specific gravity,and soil salt content were significantly reduced.The soil field capacity,the contents of organic matter,available phosphorus,available potassium,and al-kaline hydrolyzable nitrogen increased significantly.According to principal component analysis,the treatment of 5%of coal gas-ification residue+30%of spent mushroom residue+10%of biochar had the best effect on soil improvement in coal mining areas.
coal gasification slagedible mushroom substratebiocharprincipal component analysisthe physical and chemical propertiessoil in coal mining areas