Bio-organic fertilizer and preparation method thereof

The invention provides a bio-organic fertilizer. The bio-organic fertilizer is prepared from the following raw materials in parts by weight: 30-50 parts of cordyceps mushroom substrate, 30-40 parts ofwheat bran, 25-40 parts of corn bran, 20-30 parts of straw powder, 20-30 parts of soybean meal, 10-20 parts of cotton seeds, 10-15 parts of medium trace elements, 0.5-1 part of a fermentation microbial inoculum and 4-8 parts of a functional microbial inoculum. The preparation method comprises the following steps: fully mixing the cordyceps mushroom substrate, a needle mushroom substrate and the fermentation microbial inoculum, carrying out primary fermentation and secondary fermentation to obtain an organic fertilizer, adding the medium trace elements, bacillus subtilis and bacillus amyloliquefaciens, and carrying out extrusion granulation to prepare the granular biological organic fertilizer. The selected raw materials are plant sources, livestock and poultry manure is avoided, and the risk that heavy metal and