1, seedling: select uniform and neat pieces of sweet potato, bright and smooth skin, no breakage, moderate size, weight of about 100-200g sweet potato as seed potato, should not be inverted rows when sowing, and to ensure that the upper part of the pieces of potato is flush. 2, land preparation: deep ploughing and deep tilling for 30cm, and then according to the target acreage production of the application of an appropriate amount of organic fertilizers, together with 25-40kg calcium superphosphate, 25-40kg potassium fertilizer, and the application of the same amount. 40kg of calcium superphosphate, 25-40kg of potash.

I. Cultivation and field management techniques of sweet potato

1, seedling

(1) Seed potato selection and processing

① Seed potato selection: select uniform and neat potato pieces, bright and smooth skin, no damage, moderate size, weight of about 100-200g of sweet potato as seed potato.

② pre-sowing treatment: before sowing, use 50% metribuzin wettable powder 200 times liquid or 25% carbendazim 200 times liquid soaked seeds for about 10 minutes.

(2) seedbed

① nursery ground: pick the wind to the sun, high terrain, good drainage and irrigation performance of the plot of land for seedling.

② seedbed soil: seedbed soil requires loose, fertile, no germs, to sandy loam is appropriate.

(3) Sowing

① Sowing: when the temperature in early spring is more than 7-8 ℃ start seedling work, that is, about 40 days before planting seedling.

② sowing points: due to the number of sprouts of the potatoes, the top position of the most, followed by the middle, the end of the least, so in the sowing of seed potatoes should be divided into the head, tail, should not be inverted rows; at the same time, the use of the top of the bottom of the method, that is, large pieces of potatoes into the soil deep, small pieces of potatoes into the soil shallow method, so that the upper part of the potatoes to maintain a level, so that the seedling out of the seedling is more neat, easy to manage.

③ sowing method: sowing method is mainly divided into 3 kinds of oblique rows, flat, straight rows, but most of the oblique rows (to the head pressure tail, the top of the back row of potatoes to press the front row of potatoes of the first one-third).

④ Sowing density: If it is a hot bed seedling, seedbed seeding density of 23-25kg / ㎡; if it is a warm bed seedling, seedbed seeding density of 20-22kg / ㎡; if it is a cold bed double seedling, seedbed seeding density of 15-18kg / ㎡.

(4) Management

①Pre-phase management: when the temperature of the fire bed reaches 30 ℃ for seeding, seeding every day after 1 ℃ until the temperature rises to 35 ℃, cease fire; 4 days later, the temperature drops to 31 ℃ or so, at this time the seed potatoes out of the seedling, during the period of about 8-9 days.

② Mid-term management: after the emergence of seedlings, the temperature is lowered to 28 ℃; when the seedlings grow to 10cm, the temperature is lowered to 25 ℃, and the film is removed to refine the seedlings; and during this period, every 4-6 days watering, and 1-2 hours after watering the film, to prevent the production of aerial roots.

③ Post-management: keep the temperature at about 25℃, wait until about 3 days before seedling picking, the temperature will be lowered to 20℃, and the temperature will be the same as the air temperature at the time of seedling picking; pouring water once in 5-6 days before seedling picking, and then no more watering.

④ Post-seedling management: seedlings can be picked when they grow to 20-25cm; on the day of seedling picking, it is not advisable to water to prevent the invasion of germs; on the second day after seedling picking, watering and fertilizer, applying 100g ammonium sulphate per square metre; after seedling picking, combined with watering and fertilizer (fertilizer is applied when there is no dew on the leaves of the seedling), nitrogen fertilizer is the main fertilizer, such as cake fertilizer, nitrogen fertilizer, human and animal manure and urine, etc., directly spreading or fertilizer, and then watering the seedlings. The main nitrogen fertilizer, such as cake fertilizer, nitrogen fertilizer, human and animal feces and urine, and so on, directly sprinkled or diluted with water and poured.

(5) strong seedling

Seedling age of 30-35 days, leaf spreading fat, moderate size, color green, 100 seedlings weighing about 750-1000g, seedling length 20-25cm, stem thickness of about 5mm, seedling stems have no aerial roots, no disease spots, the overall upright and sturdy.

2, land organization

(1) choose a deep layer of soil, loose and fertile soil, better permeability of the plot of land for planting.

(2) Before sowing, deep plowing and deep turning about 30cm, improve soil aeration.

(3) If the target mu yield is 1500-2000kg, apply 2000-2500kg of rotted organic fertilizer per mu. If the target mu yield is 2000-2500kg, apply 2500-3500kg of well-decomposed organic fertilizer per mu. If the target yield is 2500-3000kg per mu, apply 4000-5000kg of organic fertilizer per mu. If the target yield is 4000-5000kg per mu, apply 7500-10000kg of well-aged organic fertilizer per mu. At the same time, 25-40kg of calcium superphosphate and 25-40kg of potash fertilizer should be applied.

(4) Single row planting on high ridges, 25-30cm in height, 70-80cm in width, 60-90cm in distance between ridges; double row planting on high ridges, 25-30cm in height, 100-120cm in width, 80cm in distance between ridges.

3. Transplanting

(1) Transplanting should be carried out when the local air temperature stabilizes at more than 15℃, and the temperature of shallow soil reaches 17-18℃, so that the soil can be transplanted at a higher temperature than the local air temperature. ℃ when transplanting, to cloudy days is preferred.

(2) If it is planted in single rows on high ridges, the spacing between plants should be controlled at 20-30cm. if it is planted in double rows on high ridges, the spacing between rows should be 40-50cm, and the spacing between plants should be 26-33cm.

(3) Transplanting methods include slanting cuttings, straight cuttings, horizontal cuttings, and boat-bottom type cuttings.

4, fertilization

(1) seedling fertilizer: about 3-5 days after transplanting, 10kg of ammonium sulfate per mu.

(2) Potato fertilizer: about 30-40 days after transplanting, apply 3.5-4.5kg of urea and 10kg of potassium sulphate per mu (if the plant grows well, the amount of fertilizer will be reduced by half).

(3) Potassium fertilizer: 90-100 days after transplanting, apply 10kg of potassium sulfate or 100-150kg of grass ash per mu.

(4) extra-root fertilizer: 90-140 days after transplanting, use 1% potassium phosphate solution, or 2-5% calcium superphosphate solution, or 5-10% grass ash filtrate, or 0.3% potassium dihydrogen phosphate solution for spraying, each time per mu of land spraying 75-100kg, every 15 days after the next continue to spraying, a *** spraying 2 times.

Second, sweet potato how to manage to high yield

1, planting methods

(1) planting, to high ridge double row planting is appropriate, than high ridge single row planting 24% yield increase.

(2) transplanting, there are mainly oblique insertion method, straight insertion method, horizontal cuttings, boat bottom cuttings, of which the boat bottom cuttings have a higher yield, compared to the oblique insertion method to be about 30% higher.

(3) In the appropriate transplanting time period, the earlier the transplanting, the more fully play the advantages of infinite propagation and growth of sweet potato, improve the yield of sweet potato.

(4) Before transplanting, the seedlings are dipped in the roots according to the soil condition. Plots with more serious underground pests, use 50ml of 18% thiamethoxam suspension diluted with 7.5-10kg of water to dip the roots. If the root rot is more serious, use 20-30ml of 30% methomyl to 15kg of water. The root is dipped in 20-30 ml of 30% methomyl and 15 kg of water.

2, management

(1) select good potato seeds for seedling, and choose strong seedlings for transplanting.

(2) early plowing, weeding, to ensure that the soil is loose, increase the permeability of the soil.

(3) For the potato field with more branches and more vigorous growth, use scissors to cut off 2-3 branches. When the potato seedling grows to 40-60cm or when the branch growth is too strong, remove the tender tip.

(4) In July-August, lift the vines 1-2 times to prevent the stem and leaves from growing in vain and consuming a lot of nutrients and water.

(5) Long-term rainy weather, timely drainage.

(6) When encountering the attack of sweet potato moths and other pests, use pyrethroids for control.