Seaweed amino acid composite liquid manure and preparation method and application thereof

The invention discloses seaweed amino acid composite liquid manure and a preparation method and application thereof, and belongs to the field of manure industry. Preparation of the seaweed amino acid composite liquid manure comprises the following steps: (1) alginate is degraded: under the condition that catalysts and hydrogen peroxide exist, the alginate is degraded to alginic acid solutions; (2) amino acid is chelated for the first time: animal fur is added to mixed acid composed of hydrochloric acid, sulfuric acid and phosphoric acid for acidolysis, and chelation of the animal fur and neutralizer under the condition that a chelating agent exists is carried out to obtain amino acid solutions; and (3) secondary chelating is carried out: the alginic acid solutions and the amino acid solutions are mixed to react, and then humic acid salt, major elements and microelements are added for the secondary chelating, and finally manure synergist is added to obtain the seaweed amino acid composite liquid manure. The prepared seaweed amino acid composite liquid manure is easily absorbed by crops and strong in physiological activity, yield of the crops is increased, quality of the crops is improved, and damage of heavy metals to human is reduced.