Preparation method and application of sludge biochar for greening

The invention discloses a preparation method of sludge biochar for greening. The preparation method comprises the following steps: pretreatment of sludge, mixing of additives, dehydration of the sludge, drying of the sludge, carbonization of the sludge and preparation of the biochar. According to the preparation method and application of the sludge biochar for greening, the pH value of sludge is detected and neutralized, so that the pH value of the extracted sludge meets the pH value required by trees in landscaping, and a proper amount of gravelly soil and sandy soil are added into the sludge, so that the sludge biochar for greening is obtained. Therefore, the biochar prepared from the sludge can better meet the growth requirements of landscaping trees, and is beneficial to the growth of the trees in landscaping; according to the invention, the sludge is prepared into the biochar, and the biochar is added into the soil in the landscaping planting process, so that nutrients in the soil are improved, the soil