Self-protection type secondary salinization soil remediation fungicide as well as preparation method and application of self-protection type secondary salinization soil remediation fungicide

The invention relates to a self-protection type secondary salinization soil remediation fungicide as well as a preparation method and application thereof. The self-protection type secondary salinization soil remediation fungicide comprises the following raw materials in percentage by weight: 5-15% of bacillus megatherium fermentation liquor, 30-45% of nitrate-containing industrial wastewater, 30-40% of an organic carbon source and the balance of water, the mass concentration of nitrate in the nitrate-containing industrial wastewater is greater than 30%; wherein the effective viable count is greater than or equal to 2 billion/mL; the preparation method comprises the following steps: proportionally adding an organic carbon source into treated nitrate-containing industrial wastewater, uniformly mixing, then proportionally adding a bacillus megaterium fermentation liquid, complementing to 100% with water, uniformly mixing, and standing for at least 12 hours, thereby obtaining the product, during application, the