▎ 摘　　要

NOVELTY - Complex fertilizer comprises basic compound fertilizer, modified humic acid, mineral oil, phosphate glass powder and water-retaining agent. The basic compound fertilizer is used as the core, and the outside is sequentially covered with a first film layer and a second film layer, the first film layer comprises modified humic acid and mineral oil, and the second film layer comprises phosphate glass powder and water retention agent. USE - As complex fertilizer. ADVANTAGE - The complex fertilizer exhibits water retention and slow release effects, inhibits the loss of soil moisture, maintains and improves the stability of soil moisture, and maintains sufficient nutrients in the soil. The method does not need to use too many organic solvents, and is pollution-free and cost-effective. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for preparing the complex fertilizer, which involves (a) mixing portion of the modified humic acid, portion of the mineral oil and water in the reactor to adjust the pH of the mixed liquid, and maintaining the pH of the mixed solution of 5-7.5, while controlling the reaction temperature between 80-120 degrees C, (b) adding the remaining modified humic acid and mineral oil, while controlling the reaction temperature of 60-90 degrees C, and continuing to mix uniformly to obtain the first film coating liquid, (c) adding the basic compound fertilizer in a boiling-type coating tower, and spraying the first film coating liquid on the surface of the basic compound fertilizer particles, and (d) preparing the second film coating solution with the pretreated phosphate glass powder and water retaining agent, continuously spraying and drying product.