Special root-inducing slow release high-efficiency fertilizer for double cropping rice and preparation method thereof

The invention discloses a special root-inducing slow release high-efficiency fertilizer for double cropping rice and a preparation and application method thereof. The preparation method comprises the following steps: mixing and blending nitrogen fertilizer and compound synergist in a blender for 3-5 minutes to obtain root-inducing slow release high-efficiency nitrogen fertilizer; and then, continuing to mix with phosphorus fertilizer and potassium fertilizer for about 5 minutes to obtain the finished fertilizer, wherein the compound synergist is prepared by uniformly mixing the following materials in percentage by weight: 3.4-3.8% of borax (B), 2-2.5% of hydroquinone (HQ), 0.9-1.4% of dicyandiamide (DCD), 33-36% of silicon fertilizer (SiO2), 9-14% of polyaspartic acid (PASP), 31-38% of humic acid (HA) and 9-12% of phosphorus activator. The finished fertilizer is used as basal fertilizer to be completely applied after rice soaking and in the early rice transplanting stage, and no additional fertilizer is required for the later stage; the amount of applied fertilizer for early rice is 40-45 kg/mu; and the amount of applied fertilizer for late rice is 50-55 kg/mu. The fertilizer disclosed by the invention has the dual effects of promoting root growth and delaying nutrient release, can greatly improve the nutrient utilization ratio and rice yield, is convenient to produce and use, and has the advantages of high technical compatibility, low cost, environment friendliness and the like.