NOVELTY - Sustained release complex fertilizer comprises e.g. 10-15 pts. diatomite (1250-2000 meshes), 5-6 pts. calcium chloride, 4-5 pts. sodium borate, 18-20 pts. potassium citrate, 23-25 pts. urea, 20-25 pts. diammonium phosphate, 15-18 pts. crop waste fermentation liquid, 4-5 pts. livestock blood plasma, 10-12 pts. vinegar residue, 1-3 pts. egg shell powder, 2-3 pts. cleavers, 1-2 pts. Szechwan Chinaberry fruit powder, 2-3 pts. soypeptide powder, 6-8 pts. earthworm feces, 4-5 pts. dried corn ear, 1-2 pts. sodium methyl p-hydroxybenzoate, 10-12 pts. crospovidone and 3-4 pts. methyl methacrylate.    USE - The complex fertilizer is useful for increasing water retention (claimed).    ADVANTAGE - The fertilizer is durable and enhances quality and yield of crops.    DETAILED DESCRIPTION - Sustained release complex fertilizer comprises 10-15 pts. diatomite (1250-2000 meshes), 5-6 pts. calcium chloride, 4-5 pts. sodium borate, 18-20 pts. potassium citrate, 23-25 pts. urea, 20-25 pts. diammonium phosphate, 15-18 pts. crop waste fermentation liquid, 4-5 pts. livestock blood plasma, 10-12 pts. vinegar residue, 1-3 pts. egg shell powder, 2-3 pts. cleavers, 1-2 pts. Szechwan Chinaberry fruit powder, 2-3 pts. soypeptide powder, 6-8 pts. earthworm feces, 4-5 pts. dried corn ear, 1-2 pts. sodium methyl p-hydroxybenzoate, 10-12 pts. crospovidone, 3-4 pts. methyl methacrylate, 4-5 pts. butyl acrylate, 1-2 pts. sodium dodecylbenzenesulfonate, 0.1-0.2 pts. ammonium sulfate, 2-4 pts. medical stone powder, 6-8 pts. polyferric sulfate and 4-5 pts. auxiliary agent including 14-15 pts. vermiculite powder, 2-3 pts. borax, 1-2 pts. amino acid chelated calcium, 1-2 pts. manganese citrate, 1-2 pts. zinc citrate, 4-6 pts. methyl methacrylate, 2-3 pts. Bacillus subtilis viable powder, 0.1-0.15 pts. organic chelated titanium, 1-2 pts. ammonium persulfate and proper amount of water. The auxiliary agent is prepared by uniformly mixing vermiculite powder and borax by adding into water and stirring, then adding organic chelated titanium, zinc citrate and methyl methacrylate, heating to 70-80 degrees C, stirring to react for 30-45 minutes, cooling to 20-35 degrees C, adding remaining components, stirring to react for 20-30 minutes, cooling and drying. An INDEPENDENT CLAIM is also included for preparing sustained-release complex fertilizer, comprising: (i) crushing cleavers and dried ear corn, then mixing with livestock blood plasma and vinegar residue, adding proper amount of water and carrying out anaerobic fermentation for 4-5 days under room temperature; (ii) mixing diatomite with crop waste fermentation liquid, grinding for 20-30 minutes to obtain diatomite slurry, adding polyferric sulfate into it under stirring condition, then adding medical stone powder, stirring for 15 minutes, adding soypeptide powder, stirring uniformly and drying the moisture to obtain diatomite coating material; (iii) dispersing methyl methacrylate, butyl acrylate and sodium dodecylbenzenesulfonate by adding proper amount of deionized water under stirring condition, adding ammonium sulfate, crospovidone and Szechwan Chinaberry fruit powder, mixing for 20-30 minutes to obtain sustained-release agent; and (iv) adding the resultant materials of step (i) and (ii) with remaining components into a granulator for granulation, spraying the sustained release coating agent on granules, carrying out hot-air drying and cooling to room temperature.