How to grow black potatoes? The latest planting techniques and methods tutorial is here
Black potatoes have high yield and strong adaptability, and their uses are very wide-ranging. According to measurements, every 100 grams of tuber contains 2.30 grams of protein, 0.10 grams of fat, 16.50 grams of carbohydrates, 11.00 milligrams of calcium, 1.20 milligrams of iron, 64.00 milligrams of phosphorus, 342.00 milligrams of potassium, 22.90 milligrams of magnesium, 0.01 milligrams of carotene, 0.10 milligrams of thiamine, 0.03 milligrams of riboflavin, 0.40 milligrams of niacin, 16.00 milligrams of ascorbic acid and 100.00 milligrams of anthocyanin. Their biggest feature is that they are rich in anthocyanin, with a content as high as 42.80 milligrams/kg, and they have multiple health benefits such as enhancing human immunity, delaying aging, strengthening the body, fighting cancer, beautifying the skin and preventing high blood pressure. Therefore, black potatoes can be used as a side dish, as a specialty dish, and also as an excellent processing raw material for extracting anthocyanin. At present, the cultivation area of black potatoes in China is still small, and the market price is 6-8 yuan per 1 kilogram, equivalent to 6-8 times that of ordinary potatoes. The yield per 667 sq m is generally about 2500 kilograms, and the economic benefit exceeds 10,000 yuan. The economic benefit is quite considerable, and the new variety and its supporting cultivation techniques have attracted much attention from farmers.
The whole growth period of black potatoes is about 93 days. They belong to a medium-early maturing variety, are drought-tolerant and cold-tolerant, have wide adaptability, and their tubers store well. They are resistant to early blight, late blight, ring rot, blackleg and viral diseases. Their seedlings are upright and dark purple. The plant clump is luxuriant and the growth vigor is strong. The plant height is generally about 60.00 cm, the main stem is well developed, the stem diameter is 1.37 cm, the stem is dark purple, the cross-section is triangular, and there are relatively few branches. The petiole is purple, the corolla is purple, the petals are dark purple, the tuber is long oval, the skin is smooth and dark purple, and the tuber flesh is dark purple with good quality. Tuber set is concentrated, with 6-8 tubers per plant, and the single tuber weight is 120-300 grams.
Land preparation
1. Plot selection: a loose, well-aerated soil plow layer is needed. Therefore, choosing sandy loam soil with high and dry terrain, flat terrain, convenient irrigation and drainage, and loose, deep and fertile soil texture is the soil foundation for ensuring a high yield.
2. Crop rotation arrangement: black potatoes should not be continuously cropped or rotated with Solanaceae crops such as tobacco, eggplant, pepper and sweet potato. Wheat, corn, Chinese cabbage, radish and Welsh onion are better as previous crops.
3. Land preparation: to achieve high yield and good variety quality of black potatoes, deep plowing should be carried out before winter in the planting field, generally to a depth of 25-30 cm. In early spring, fine land preparation should be carried out to achieve fine soil without large clods and enhance the soil's water-holding capacity.
4. Apply sufficient base fertilizer. Black potatoes are a high-yield and fertilizer-loving crop. Every 100 kilograms of fresh tubers produced requires 0.50 kilograms of nitrogen, 0.20 kilograms of phosphorus and 0.95 kilograms of potassium, and the absorption ratio of nitrogen, phosphorus and potassium is generally 2:1:4. Cattle, sheep, pig and chicken manure, green manure and compost should be the main materials, supplemented with an appropriate amount of chemical fertilizer. Determine the fertilization plan according to the soil nutrient test results and fertilizer requirement patterns. Combined with land preparation, apply 3-5 sq m of decomposed organic fertilizer, 80-100 kilograms of superphosphate, 15-20 kilograms of potassium sulfate fertilizer and 15 kilograms of urea per 667 sq m.
Seed potato treatment
1. Carefully select seed potatoes. 20-30 days before planting (generally around mid-January in this region), carry out seed potato selection, choosing seed potatoes that are disease-free, wound-free, smooth-skinned, fresh in skin color, with many eyes, uniform in size and conforming to the variety characteristics, and remove tubers that are deformed, cracked, have necrotic eyes or bear disease spots. About 120 kilograms of seed potatoes are needed per 667 sq m. It is best to cut the sprouts into pieces about one liang each, as this will give a very high yield.
2. Cutting seed potatoes into pieces and sprouting. Sprouting before sowing can promote early emergence, increase the field growth period and raise yield. Sunny beds, cellars and greenhouses can all be used as sprouting sites. Place the selected seed potatoes in a dark environment at 20°C for warm sprouting. When the sprouts emerge about 0.5 cm, cut into pieces. According to the arrangement order of the eyes, start from the tail end of the tuber and cut in a spiral shape according to the order of the eyes. Finally, split the top part into two. Ensure that each cut piece carries 1-2 strong top buds. The cut pieces should be uniform, and generally the weight of each seed potato piece should remain about 25 grams. The knife used for cutting must be strictly disinfected with 75% alcohol.
3. Chemical treatment. Put the cut tubers into 0.01% boric acid or a 500-fold 50% carbendazim solution, soak for 5-10 minutes, then remove, drain and dry in the shade. Move the dried tubers to a warm, sunny place and sun the seed potatoes for 3-5 days, maintaining a temperature of about 15°C, so that the young sprouts turn green and become strong.
Sow at the right time
1. Planting period. Black potato sprouts begin to germinate when the temperature exceeds 5°C. At 18°C they grow robustly and rapidly. Under normal circumstances, sowing can begin when the soil temperature steadily passes 5°C. In the Tianjin area, the suitable open-field cultivation mode generally has a planting period from mid-to-late March to early April. If too early, the seedlings are prone to frost damage; if too late, they cannot be marketed early, affecting planting benefits.
2. High-ridge plastic film mulching. Double-row cultivation with high-ridge plastic film mulching can increase the soil temperature by 3-5°C, advance the planting period by about 15 days, and at the same time create a healthy and loose environment for the normal growth of black potatoes, and also facilitate manual or mechanical harvesting. Make turtle-back ridges with a row spacing of 100 cm, a height of 20 cm and a width of 70 cm, with the middle slightly higher. After raking level, spray 100-150 grams of acetochlor mixed with 40-50 kilograms of water per 667 sq m to control field weeds: use plastic film with a width of 90 cm and a thickness of 0.008 mm for mulching. The mulching should be tight, and a strip of soil should be pressed horizontally every 2-3 m to prevent strong winds from lifting the film. After mulching and warming the ridges for 3-5 days, planting can begin.
3. Reasonable close planting. Black potatoes are suitable for sparse planting. Use double-row cultivation, with a row spacing of 40 cm and a plant spacing of 33 cm, leaving about 4000 plants per 667 sq m. When planting, use a hole punch to make planting holes 8-10 cm deep according to the plant and row spacing. Then place the seed potatoes with the sprouts facing up, and seal the film holes tightly with fine soil.