The present invention provides an afforestation method using a soil mixture for afforesting a cut slope, wherein 7 to 10 wt% of pyroligneous liquor fermented rice straw which is an organic byproduct 10 to 20 wt% of pureed soybean residues, 10 to 20 wt% of flour, 10 to 25 wt% of compost, 5 to 7 wt% of coconut shells, 15 to 30 wt% of ocher, 7 to 15 wt% of a bacillus which is a soil microorganism, 7 to 15 wt% of an amino acid liquefied fertilizer, and 10 to 25 wt% of terra cotta are mixed so that the soil mixture for afforesting a cut slope is produced. The pyroligneous liquor fermented rice straw, pureed soybean residues, and coconut shells are dipped in a vegetable adhesive so that the vegetable adhesive is coated on the surfaces thereof. Then, the pyroligneous liquor fermented rice straw, pureed soybean residues, and coconut shells are taken out and dried for 30 to 45 hours to have a water content of 7 to 12%, wherein the pyroligneous liquor fermented rice straw, pureed soybean residues, and coconut shells are wetted in water to be used and mixed. By means of the present invention, seeds of herbal plants are mixed with various organic compositions in order to be planted in a cut slope so that the cut slope can be afforested in an environmentally friendly manner, and soil is modified so that the germination of the seeds can be promoted. Moreover, seeds of herbal plants are mixed with the soil mixture including the pyroligneous liquor fermented rice straw, pureed soybean residues, and coconut shells, on which the vegetable adhesive is coated, and planted in a cut slope, so that excellent adhesion is maintained and cracks, partial desorption, and sliding can be continuously prevented.본 발명은 유기질 부산물인 목초액 발효 볏짚 7 내지 10 중량%, 콩비지찌꺼기 10 내지 20 중량%, 밀가루 10 내지 20 중량%, 퇴비 10 내지 25 중량%, 코코넛껍질 5 내지 7 중량%, 황토 15 내지 30 중량%, 토양미생물인 바실러스 7 내지 15 중량%, 아미노산 액비 7 내지 15 중량% 및 토양보습제인 테라코템 10 내지 25 중량%를 혼합하여 절토사면 녹화용 토양혼합물을 구성하되, 상기 목초액 발효 볏짚, 콩비지찌꺼기 및 코코넛껍질은 표면에 식물성 접착제가 도포되도록 상기 식물성 접착제에
