Liquid fertilizer used for eggplant based on biogas slurry and its application method

The invention relates to a liquid fertilizer used for eggplant based on biogas slurry and its application method, which comprises the following steps by weight: 70-90 parts of biogas slurry, 10-15 parts of ammonium nitrate, 3-5 parts of dipotassium hydrogen phosphate, 5-8 parts of potassium chloride, 1-3 parts of calcium nitrate, 0.8-1.5 parts of ferrous sulphate, 0.5-0.8 parts of magnesium chloride, 0.2-0.5 parts of zinc sulfate, 0.5-1.5 parts of boric acid, 0.3-0.5 parts of manganese sulfate and 0.2-0.5 parts of ammonium molybdate. According to the invention, the biogas slurry which is obtained by anaerobic fermentation of livestock and poultry excrement and crop straw through a methane tank, the nutrient composition required by the growth of the eggplant can be scientifically added to prepare the liquid fertilizer. The liquid fertilizer has the advantages of comprehensive nutrition, sufficient raw material source, low cost and safe environmental protection. The liquid fertilizer is diluted by using clear w