Method and device for preparing nitro-fulvic acid by fermenting cow dung

The invention relates to a method and device for preparing nitro-fulvic acid by fermenting cow dung; specially-cultured special compound microorganisms are used as a fermentation microbial inoculum, cow dung is fermented, so as to directionally generate a fulvic acid product mainly containing aromatic hydroxy carboxylic acid, and the defects of blind fermentation by using a common microbial inoculum and low fulvic acid yield are overcome. A nitric acid mild catalytic oxidation technology is adopted, so that the molecular weight of macromolecular biochemical humic acid and fulvic acid is reduced, the content of acidic functional groups is increased, nitro is introduced into aromatic molecules, and the activity of the acidic functional groups is further improved; worm eggs, harmful bacteriaand viruses in excrement can be eliminated through nitric acid oxidation, and the safety of the product is guaranteed; the obtained nitro-fulvic acid is mainly used as a high-efficiency plant growth regulator or a water-solub