NOVELTY - Nitrogen sustained-release fertilizer comprises 8-10 pts. wt. pest-free Chrysanthemum stem and leaves, 4-6 pts. wt. isobutylene diurea, 6-7 pts. wt. urea, 4-5 pts. wt. ammonium sulfate, 45-60 pts. wt. rapeseed cake, 4-5 pts. wt. ferrous sulfate, 4-6 pts. wt. zinc sulfate, 5-6 pts. wt. manganese, 8-12 pts. wt. diatomite, 5-8 pts. wt. monoammonium phosphate, 32-40 pts. wt. silkworm excrement, 12-16 pts. wt. soybean, 9-15 pts. wt. vegetable shavings, 3-4 pts. wt. microbial agents, 4-5 pts. wt. soil modifying agent, and water (suitable quantity).    USE - As nitrogen sustained-release fertilizer for strawberry (claimed).    ADVANTAGE - The nitrogen sustained-release fertilizer has excellent degradability.    DETAILED DESCRIPTION - Nitrogen sustained-release fertilizer comprises 8-10 pts. wt. pest-free Chrysanthemum stem and leaves, 4-6 pts. wt. isobutylene diurea, 6-7 pts. wt. urea, 4-5 pts. wt. ammonium sulfate, 45-60 pts. wt. rapeseed cake, 4-5 pts. wt. ferrous sulfate, 4-6 pts. wt. zinc sulfate, 5-6 pts. wt. manganese, 8-12 pts. wt. diatomite, 5-8 pts. wt. monoammonium phosphate, 32-40 pts. wt. silkworm excrement, 12-16 pts. wt. soybean, 9-15 pts. wt. vegetable shavings, 3-4 pts. wt. microbial agents, 4-5 pts. wt. soil modifying agent, and water (suitable quantity). The soil modifying agent comprises 3-4 pts. wt. borax, 30-40 pts. wt. diatomite, 5-6 pts. wt. oyster shell, 4-6 pts. wt. biogas, 10-12 pts. wt. iron ore, 8-10 pts. wt. sea pumice, 14-18 pts. wt. Kanuma soil, 2-3 pts. wt. manganese sulfate, 6-8 pts. wt. sodium polyacrylate, 8-10 pts. wt. sodium alginate, 10-16 pts. wt. zinc sulfate, 8-14 pts. wt. ammonium citrate, 15-20 pts. wt. charcoal, 6-7 pts. wt. water, and 3-4 pts. wt. tea oil. The soil modifying agent is prepared by mixing zinc sulfate, ammonium citrate and charcoal, grinding mixture, drying mixture, granulating mixture, adding sodium polyacrylate to the granules, adding sodium alginate, water and manganese sulfate to the mixture, stirring the mixture for 10-30 minutes, adding the remaining materials to the mixture, crushing the mixture to mesh size of 80-120, adding Camellia oil in a dropwise manner, stirring the mixture and drying the stirred mixture. An INDEPENDENT CLAIM is included for method for preparing the above-mentioned nitrogen sustained-release fertilizer, which involves (a) mixing ammonium sulfate, ferrous sulfate, zinc sulfate, manganese and monoammonium phosphate, crushing the mixture to mesh size of 40-80, adding water to the mixture and uniformly stirring the mixture, (b) mixing the urea, ammonium sulfate, rapeseed cake, silkworm excrement, and soybean, adding water to the mixture, stirring the mixture into paste, adding microbial agents to the paste and fermenting the mixture at room temperature for 10-20 days, (c) mixing the pest-free Chrysanthemum stem and leaves, diatomite and vegetable shavings to the mixture obtained in the step (b), adding water to the mixture, heating the mixture for 20-30 minutes, cooling the heated mixture, fermenting the mixture for 7-12 days, turning the fermented mixture for every 24-48 hours and drying and granulating the fermented mixture, and (d) uniformly mixing the products obtained in step (a) and (c).