Preparation method for improving saline-alkali soil by microorganisms and metabolites thereof

The invention relates to the technical field of soil improvement agents, in particular to a preparation method for improving saline-alkali soil through microorganisms and metabolites of the microorganisms. Comprising the following components in percentage by weight: 35-50% of compound microbial bacteria and dried metabolites thereof, 8-15% of spent bleaching clay, 5-10% of sulfuric acid production leftover waste residues, 5-8% of power plant chimney ash, 3-5% of polyvinyl alcohol, 2-4% of polyaspartic acid and the balance of bone meal factory leftovers. Sulfuric acid production leftover waste residues and powder plant leftovers are crushed by a crusher, sieved by a 100-mesh sieve, and sterilized; the preparation method has the beneficial effects that after the prepared microorganisms and metabolites thereof are put into saline-alkali soil improvement, the soil improvement effect is obvious, root systems are developed, seedlings emerge early, and the seedlings are neat and strong; the problem that an existing