The preparation method comprises the following steps: preparing an
enzyme 1: collecting
protein casing waste, adding a preset
leavening agent into the
protein casing waste, carrying out
fermentation treatment for 6-10 hours, sterilizing, cooling and filtering to obtain a filtrate which is the
enzyme 1; preparing
enzyme 2: taking couchgrass roots, adding water, pulping, separating pulp from residues, taking pulp, adding PBS
mother liquor into the pulp, inoculating bacterial
powder, and performing sealed
fermentation for 40-52 hours to obtain the enzyme 2; preparing an enzyme 3: taking Chinese mesona
herb and an
alcohol solution, performing reciprocating oscillation for 5-8 hours, performing
filtration, taking filtrate, diluting the filtrate by 10-20 times, then inoculating the bacterial liquid, keeping the ventilatory capacity of 0.08 m < 3 > / (m < 3 >. Min)-0.15 m < 3 > / (m < 3 >. Min), performing aerobic
fermentation for 4-6 days, performing
filtration, taking filtrate, and adjusting the pH value of the filtrate to 7.0-8.0 to obtain the enzyme 3; and mixing the enzyme 1, the enzyme 2 and the enzyme 3 to prepare the nutritional additive for increasing the yield of the sugarcane. Compared with the prior art, the
nutrient additive containing high acid-soluble
protein, flavone,
organic acid and salts thereof and effective active
bacteria is prepared, and the
nutrient additive promotes the development of sugarcane root systems, increases the sugarcane leaf area, improves the
photosynthesis rate and improves the sugarcane yield; the problems of soil degradation,
nutrition imbalance and the like caused by
continuous cropping of sugarcane are solved, and the
soil ecology and
soil fertility are restored.