The present invention is a sweet potato seed preparation step of preparing a sweet potato seedling obtained by cutting a first node from the root of a sweet potato seedling having a length greater than or equal to 25 cm and less than or equal to 45 cm in a green house at an angle of 45 degrees； An immersion step of immersing the stem portion of the sweet potato seedling in water at 21° C. for 36 hours； A first herbicidal step of spraying a herbicide 10 to 12 days before planting the sweet potato seedlings in the soil for planting the sweet potato seedlings immersed in the water； A complex fertilizer supply step of supplying 250 to 350 kg of a complex fertilizer with a weight ratio of 150:80:80 per 1 ha of nitrogen:phosphorus:potassium to the soil to plant the sweet potato seedlings immersed in the water； A duduk forming step of forming a duduk having a depth of 50 to 70 cm and a height of 50 to 60 cm in the soil to plant the sweet potato seedlings immersed in the water； A mulching step of installing a drip tape capable of supplying water or nutrients on the top of the duke, mulching the two adjacent duke and the middle furrow of the duke with vinyl, and punching a hole for planting sweet potato seeds in the mulched vinyl； A formal step of planting a sweet potato seedling by inserting from the third to the fifth stem of the sweet potato seedling immersed in water into the hole； A second herbicidal step of spraying a herbicide after planting the sweet potato seedlings； And a mixed fertilizer obtained by mixing 70 to 150 kg of a complex fertilizer having a weight ratio of 150 to 250 kg of ammonium nitrate and nitrogen: phosphorus: potassium per ha of 150: 80: 80 per ha in the soil where the sweet potato seedlings are planted. It relates to a method of cultivating sweet potatoes in sandy soil comprising a； mixed fertilizer supply step of feeding times to six times.본 발명은 비닐하우스에서 키운 길이가 25 cm보다 크거나 같고 45 cm보다 작거나 같은 고구마 종묘를 뿌리로부터 첫 번째 마디를 45 도의 각도로 잘라낸 고구마 종묘를 준비하는 고구마 종묘
