Purple sweet potato belongs to the genus Ipomoea of Convolvulaceae, and its pulp is purple to deep purple, so it is also called black sweet potato, purple sweet potato or purple sweet potato. Purple sweet potato is a special variety of sweet potato, which has the characteristics of edible, economic and medicinal crops. Besides the components and functions of common sweet potato, it also has many physiological functions and is an important raw material for food, medicine, chemical industry, light industry, textile and other industries.
Purple sweet potato contains 10 mineral elements such as selenium, zinc, iron and phosphorus, 18 amino acids, and 8 vitamins such as vitamins C, B and A, especially anthocyanins, which have great medicinal value. Can be used for extracting natural anthocyanins; Beautiful appearance, purple-black skin color and purple flesh color. The potato shape is long and spindle-shaped, and the potato skin is smooth and bright, with good commodity. The commodity rate is over 90% and the drying rate is about 33%.
The growth habits and elements of purple sweet potato are different from other sweet potatoes, and black, purple, sandy land and yellow soil are required to be better. Planting purple potato requires deep ploughing in advance, intensive cultivation, large ridge cultivation, water permeability and adequate fertilization (reasonable distribution of nitrogen, phosphorus and potassium fertilizer).
Purple sweet potato is usually planted in 1 year 1 crop. When the temperature is higher than15 C, the earlier the cutting, the better. When the seedlings grow to 9 ~ 10 leaves, they can be cut, and weeding and topdressing can be carried out 1 time the next day after cutting. Generally speaking, it is best to cut spring potatoes from late April to May, summer potatoes must be finished before early June, and seeds can be planted before the end of July at the latest, but it will affect the yield of purple potatoes. Potato seedlings should be inserted horizontally and obliquely, with a depth of 3 nodes and a variety of potatoes between nodes.