What variety is the American black sweet potato? An article to help you understand
The American black sweet potato is a new black-red sweet potato variety introduced from the United States. The leaves are heart-shaped, without notches, with short vines (70-100 cm long), many branches at the base, and the top three leaves are purple-red. Each plant produces 4-6 tubers, each weighing 100-500 grams, with a maximum of 1 kg. It produces many and uniform tubers. The general yield per mu is: spring sweet potatoes 4000-5000 kg, summer sweet potatoes around 3000 kg. The tubers are spindle-shaped, with purple-black skin like dragon shells, and purple-red flesh, beautiful and attractive. After cooking, they are entirely purple-black, sweet, fragrant, mealy, and sandy, with good eating quality and high nutritional value. Rich in anti-cancer substances selenium and iodine, each kilogram of fresh sweet potato contains 23 grams of protein, 290 grams of sugar, 6.80 grams of VA, 200 mg of phosphorus; the content of lysine, carotene, iron, zinc, calcium, etc. is higher than ordinary sweet potatoes. It is praised as a "green health food" in the United States.
Key cultivation techniques:
1 Apply sufficient base fertilizer, deep plow and ridge Apply 4000 kg of high-quality farmyard manure, 40 kg of ammonium bicarbonate, 60 kg of superphosphate, 20 thousand yuan of potassium sulfate per mu, deep plow more than 25 cm, form large ridges, ridge height 30 cm, top width 40-50 cm, bottom width 90 cm, ditch bottom width 30 cm, and plant double rows on the ridge surface when transplanting seedlings.
2 Timely early planting of strong seedlings Sweet potato is a crop with indeterminate growth. Under suitable temperature conditions, the longer the growth period, the higher the yield. Spring sweet potatoes with plastic film mulching can be planted 10-15 days earlier, and the film can be broken to release seedlings after the frost-free period, increasing yield by more than 30% compared with cultivation without film. For open-field cultivation, plant hardened, high-cut strong seedlings, with a seedling height of about 25 cm. When planting, plant one row on each side of the ridge surface. For spring sweet potatoes, plant 3500-4000 plants per mu; for summer sweet potatoes, 4000-5000 plants. Under the condition of ensuring survival, plant as shallowly as possible. Leave 5 cm above ground, and bury the rest horizontally along the ridge in the soil, with a burial depth of 5-8 cm. Water thoroughly, and after the water seeps down, cover tightly with fine soil. Finally, spray "acetochlor" on the soil surface to prevent weed damage.
3 Scientific management About 5 days after planting, check seedlings and fill gaps. About 20 days later, if there is drought, water along the ditch. Pay attention to drainage during the flood season. At the early stage of tuber formation, apply 1 topdressing of potassium sulfate compound fertilizer. After the vines close the ridges, spray paclobutrazol 2-3 times to prevent excessive vine growth. It is strictly forbidden to turn the vines. If roots form after rain, lift the vines along their direction. At the middle and late stages of tuber formation, spray "sweet potato tuber expansion agent" and potassium dihydrogen phosphate 2-3 times to promote tuber root expansion and increase yield. If pests damage the leaves, the foliar fertilizer can be mixed with insecticide and sprayed.