The invention belongs to the field of
chemical engineering, and relates to a preparation method of a water-retention and
nitrogen-fixation slow release water-soluble
fertilizer. The method comprises the following steps: preliminarily mixing a
nitrogen fertilizer, a high-molecular material, a water retaining agent and a filler, adding above preliminarily
mixed materials to a
solid-liquid mixer, continuously stirring and mixing the preliminarily
mixed materials, adding water and auxiliary agents at a constant stirring rate, carrying out preliminary kneading, adding the above obtained mixture to an extruding and kneading device, adding water, carrying out secondary kneading to prepare a paste, continuously sending the paste to a granulator, granulating the paste,
drying prepared granules, sieving the dried granules, and packaging the sieved granules to obtain the final water-retention and
nitrogen-fixation slow release water-soluble
fertilizer. The high-molecular material
polyacrylamide is effectively added to a chemical fertilizer in order to reduce soil
erosion and effectively improve the
soil structure, so the total
porosity and the
capillary porosity of the soil are increased, and the soil capacity is reduced, thereby soil granules and the pore structure keep stable. Polypropionamide substantially inhibits the loss of the nitrogen element and improves the
nitrogen fertilizer utilization rate.