Preparation method of biological agent organic fertilizer

The invention relates to the technical field of organic fertilizer preparation, and discloses a preparation method of a biological agent organic fertilizer, the preparation method comprises the following steps: S1, soaking cow dung for 10-15 days for preliminary fermentation, and then carrying out dry-wet separation dehydration until the water content is 50-60%; s2, mixing the dehydrated cow dung with oil cake and vinasse according to a weight ratio of (6-7): (1.5-2): (1-2) to form a basic raw material; s3, mixing an organic fertilizer fermentation inoculant with water according to the weight ratio of 1: 20 and then applying to the basic raw materials, wherein the weight ratio of the organic fertilizer fermentation inoculant to the basic raw materials is 1: 2000; s4, controlling the moisture content of the raw materials after the organic fertilizer fermentation inoculant is added to be 45%-55%; s5, uniformly stirring the raw materials by using a stirrer, spreading until the thickness is 70-80cm, stacking, cov