The invention relates to a preparation method of a double-membrane multifunctional
controlled release fertilizer and belongs to the technical field of
fertilizer production. The preparation method comprises the following steps: spraying ethyecellulose internal coated film liquid to the surfaces of
fertilizer cores, so as to obtain single-membrane fertilizer particles after
ethanol volatilizes; spraying a
glutaraldehyde solution to the outer sides of the single-membrane fertilizer particles, and spraying an inhibitor-adsorbed high-water-retention adsorption type external coated
film material, so as to obtain the double-membrane multifunctional
controlled release fertilizer. The internal coated film and the external coated film are made from a
cellulose-base material, so that the preparation method is environment-friendly; by utilizing an inhibitor, an antihydrolysis effect is achieved while the fertilizer is slowly released, the
nitration and
decomposition of effective components are inhibited, and the
utilization rate of the fertilizer is increased; and meanwhile, high-water-retention adsorption type resin is an external coated film, so that the water absorption amount of a fertilizer product can be effectively improved, the water-retaining property is strong, the water-holding capacity of soil is increased, and the fertilizer is suitable for being applied in easily-
arid regions with changeable climate.