NOVELTY - Composite fertilizer comprises 6-8 pts. wt. quartz sand, 2-3 pts. wt. sodium alginate, 8-10 pts. wt. pig manure, 6-8 pts. wt. rice bran powder, 7-8 pts. wt. soybean curd residue, 3-4 pts. wt. activated carbon, 10-12 pts. wt. bentonite, 14-16 pts. wt. castor, 2-3 pts. wt. bio-fermentation agent, 8-10 pts. wt. magnesium sulfate, 3-5 pts. wt. potassium borate, 5-7 pts. wt. calcium superphosphate, 3-4 pts. wt. magnesium oxide, 10-14 pts. wt. ammonium sulfate, 4-5 pts. wt. auxiliary agent and water (suitable amount). The auxiliary agent comprises e.g. tetrachlorophthalide.    USE - The composite fertilizer is useful for planting plum (claimed).    ADVANTAGE - The composite fertilizer controls the hydrating process while planting plum under stringent conditions; maintains soil under moist state, and neither in partial wet state, too dry nor too wet state; reduces compaction of quartz sand with soil, and labor intensity; facilitates three-dimensional spatial structure of loose soil, so as to allow moisture penetration, and uniform distribution of nutrients; increases the flow of nutrients, and flowering rate; comprising cross-linked sodium alginate colloidal substances which facilitate sustained-release of nutrients, without frequent addition of fertilizer; and does not chemical composition which when concentrated causes burning to plant roots.    DETAILED DESCRIPTION - Composite fertilizer comprises 6-8 pts. wt. quartz sand, 2-3 pts. wt. sodium alginate, 8-10 pts. wt. pig manure, 6-8 pts. wt. rice bran powder, 7-8 pts. wt. soybean curd residue, 3-4 pts. wt. activated carbon, 10-12 pts. wt. bentonite, 14-16 pts. wt. castor, 2-3 pts. wt. bio-fermentation agent, 8-10 pts. wt. magnesium sulfate, 3-5 pts. wt. potassium borate, 5-7 pts. wt. calcium superphosphate, 3-4 pts. wt. magnesium oxide, 10-14 pts. wt. ammonium sulfate, 4-5 pts. wt. auxiliary agent and water (suitable amount). The auxiliary agent comprises 4-6 pts. wt. polyethylene glycol, 2-4 pts. wt. tetrachlorophthalide, 3-5 pts. wt. sodium nitrophenolate, 1-12 pts. wt. yellow phosphorus slag, 6-8 pts. wt. ammonium nitro-humate, 3-4 pts. wt. ammonium alum, 1-2 pts. wt. alpha -lipoic acid, 2-3 pts. wt. n-butanol and water (suitable amount). The preparation comprises (i) grinding yellow phosphorus slag into fine powder of 200-mesh sieve, and mixing with ammonium nitro-humate, into a powder form; (ii) dissolving polyethylene glycol and n-butanol mixture by adding water, where the ratio of polyethylene glycol and n-butanol, is 1:10, and then adding tetrachlorophthalide, sodium nitrophenolate, ammonium alum and alpha -lipoic acid, stirring while heating to dissolve for 1-2 hours, to obtain an aqueous agent; and (iii) adding the powder into aqueous agent, and stirring while uniformly mixing, drying, and crushing to obtain the product.    An INDEPENDENT CLAIM is also included for preparing the composite fertilizer, comprising (a) mixing pig manure, rice bran powder, soybean curb residue, activated carbon, bentonite and castor, carrying out primary crushing by adding bio-fermentation agent and water in a ratio of 1:10 to dissolve, spraying the solution onto the mixed organic material, uniformly mixing, adjusting the water content at 25%, fermenting for 1-16 days under conditions of 36-39 degrees C, and stirring once in every 3 days; (b) mixing magnesium sulfate, potassium borate, calcium phosphate, magnesium oxide, ammonium sulfate and auxiliary agent with the other residual components, adding water in an amount of 4 times, and stirring while heating to dissolve in water; (c) adding sodium alginate powder into aqueous agent, in a ratio of 1:100, supplementing with water according to certain standards, heating while stirring, and dissolving, then adding quartz sand, stirring at room temperature of 20-30 minutes, and cooling to obtain jelly-form compound; and (d) mixing the organic material with the jelly-form compound, mechanically rolling while stirring for 8-10 minutes, drying, adjusting the water content to less than 20%, carrying out ultra-micro crushing, granulating, until the particle diameter is 3-6 mm, and placing the mixture into a bag film.