The invention discloses a method for preparing biocontrol active liquid seaweed fertilizers, and belongs to the technical field of agricultural bio-fertilizers. The method includes the steps that degummed seaweed dregs are subjected to ultrasonic treatment to obtain a first sample, and then compound enzymes are added into the first sample to carry out reacting;
solid-liquid separation is carried out on enzymolysis reactants, and enzymatic
hydrolysate is collected; finally, water-soluble
chitosan with the degree of deacetylation larger than 90% and water-soluble
chitosan oligosaccharide with the molecular weight
ranging from 2,000 to 3,000 are added into the enzymatic
hydrolysate, and the composite liquid fertilizers are prepared. As the degummed seaweed dregs are subjected to ultrasonic treatment, the structures of fibers can be changed under the acoustic
cavitation effect of ultrasonic
waves, amorphous regions of the fibers are enlarged accordingly, following
enzymatic hydrolysis can be efficiently carried out easily, and the
reaction speed and the reaction yield are increased. The oligomerization
chitosan and seaweed dreg extract are compounded, the advantages of the two kinds of raw materials are complemented, the fertilizers are more complete in function and higher in
fertilizer effect, and the fertilizers prepared with the method are novel seaweed biocontrol fertilizers having the treatment function, the
disease preventing function and the
nursing function at the same time.