Water and fertilizer retention organic fertilizer and preparation method thereof

The present invention discloses a water and fertilizer retention organic fertilizer made of the following raw materials by weight: 20-30 parts of sorghum straw charcoal powder, 6-8 parts of river silt, 2-3 parts of potassium mineral powder, 1-2 parts of calcium hydrogen phosphate, 4-5 parts of EDTA chelated zinc, 4-6 parts of died sweet potato, 5-6 parts of fulvic acid, 4-5 parts of durian shell, 3-4 parts of sunflower oil slag, 4-5 parts of potassium sulfate, 6-8 parts of ammonium nitrate, 35-45 parts of rape straw, 6-8 parts of gracilaria lemaneiformis, 8-10 parts of safflower seed oil residue, 20-30 parts of a soil conditioner, and the proper amount of water; the raw materials adopted by the fertilizer are wide in sources, are mainly non-pollution production waste, and effectively reduce the production cost, by a compounded coated granular structure, the fertilizer release time can be prolonged, soil water and fertilizer retention capacity can be improved, and the soil absorption, buffer and resistance properties can be improved.