NOVELTY - Orange tree slow release organic fertilizer comprises soybean curd residue, rice bran, bone meal, coal slag, fermentation agent, urea, calcium citrate, molybdenum powder, copper sulfate, ammonium chloride, borax, oil refinery rapeseed dregs, lees and old rice. The fertilizer is obtained by stirring soybean curd residue, bran, bone meal and coal slag, adding fermentation agent to obtain material A, mixing urea, calcium citrate, molybdenum powder, copper sulfate, ammonium chloride and borax to obtain material B, dissolving in water, adding material A, fermenting, mixing with rapeseed dregs.    USE - Used as orange tree slow release organic fertilizer.    ADVANTAGE - The fertilizer: comprises easily available raw materials; is economical; improves the utilization of macroelements; and provides trace elements required for the growth and increasing capacity of slow release fertilizer.    DETAILED DESCRIPTION - Orange tree slow release organic fertilizer comprises 35-45 pts. wt. soybean curd residue, 20-25 pts. wt. rice bran, 13-18 pts. wt. bone meal, 7-8 pts. wt. coal slag, 5 to 7 pts. wt. fermentation agent, 2-4 pts. wt. urea, 1.5-3 pts. wt. calcium citrate, 0.5-0.8 pts. wt. molybdenum powder, 0.5-1.2 pts. wt. copper sulfate, 1-3 pts. wt. ammonium chloride, 0.5-0.8 pts. wt. borax, 7-8 pts. wt. oil refinery rapeseed dregs, 0.5-0.8 pts. wt. lees and 30-45 pts. wt. old rice. The preparation of the fertilizer comprises (a) stirring soybean curd residue, bran, bone meal and coal slag in a stirrer for 20-25 minutes at a speed of 50-60 revolutions/minute at 80-90 degrees C, cooling to 25-27 degrees C, adding fermentation agent, mixing uniformly to obtain material A, where the fermentation agent has viable cell count of greater than or equal to 2x 108 cells/g, (b) mixing urea, calcium citrate, molybdenum powder, copper sulfate, ammonium chloride and borax in a mixer at 30-32 degrees C to obtain material B, (c) dissolving material B in water to prepare a solution having concentration of 0.25-0.4 wt.%, adding material A, mixing uniformly at 32-36 degrees C, fermenting for 7-8 days to obtain material C, (d) mixing the material C with oil refinery rapeseed dregs, drying at room temperature in dark for 7-8 days, crushing and drying the mixture, and (e) adding old rice, uniformly mixing, crushing, and sieving.