Pollution-free cultivation techniques of mini sweet potato

Mini sweet potato is a small vegetable sweet potato with a mass of 50g and 150g, fine texture and strong flavor. Mini sweet potato is suitable for microwave baking or whole cooking in modern small families, and coarse grains are eaten together. The price of mini sweet potato in supermarkets in Hangzhou and Shanghai is 4 times higher than that of ordinary sweet potato. It is deeply loved by consumers and its planting area is rising rapidly. 1. Environmental selection: the planting site is selected according to the environmental conditions standard of pollution-free food-vegetable producing area. At the same time, the soil is required to be loose Xinkai red soil, yellow soil or sandy flood-drought rotation land, and the soil is somewhat acidic. 2. Variety selection: Jinyu (formerly Zhe 1257). Bred by Zhejiang Academy of Agricultural Sciences, the skin color is pink, the flesh color is pure yellow, the potato pieces are short and round, the skin is smooth, the taste is pink, sweet, waxy, delicate texture, no crude fiber (gluten), strong flavor, drying rate 30% 32%, 7 potatoes per plant, uniform size, good early maturity, can be harvested in about 110 days, suitable for planting in different seasons, the commodity potato rate can reach 85% 50g or less also has its own characteristics. It is suitable for consumption in hotels and restaurants. This variety has good seedling emergence and general drought tolerance, and its main disadvantage is that it is susceptible to vine cutting disease. the effective measure to avoid the disease is to choose disease-free seed potato, high-cutting seedlings and taboo continuous cropping, and the control effect of flood-drought rotation is better. Liangyuan (formerly known as AIS). Varieties introduced from abroad. The skin is golden, the flesh is red, the potato is round, the skin is smooth, the taste is soft, sweet and waxy, the quality is excellent, and the flavor is strong; the drying rate is 25% 26%, which is suitable for cooking or baking, 5 to 6 potatoes per plant, and the potato pieces are uniform in size. The sprouting is good and the growth period is about 130 days. Heart incense. A new variety selected by Zhejiang Academy of Agricultural Sciences. Purple-red skin and yellow meat, oval potato pieces, smooth epidermis, pink taste, delicate texture, sweet, drying rate 27%-29%. The underground part of the tuber is shallow and concentrated, which is suitable for mechanized harvesting. There are 6 to 7 tubers per plant, and the size of tubers is uniform. This variety has good early maturity and high yield. it can be harvested in 90 days by plastic film mulching from late April to early May. Its yield and maturity are similar to that of high-yielding variety Sushu 8, and it can be planted for two seasons a year in Zhejiang Province. Zhejiang potato 6025. Purple red tangerine red meat, potato oval, smooth skin, just harvested, taste powder, after storage (November), starch degradation; taste soft, waxy, sweet, good flavor. The supply market is better since November, with a small amount of crude fiber at both ends and a drying rate of 28% to 32%. There are 5-7 tubers per plant with good seedling emergence, semi-erect aboveground parts, vigorous growth, dark green leaves, medium vines, medium maturity, growing period of more than 120 days, and better planting in the first and middle of June. Zhejiang Shu 78. Red skin orange red meat, round potato pieces, smooth skin, soft, sweet, waxy taste, a small amount of crude fiber at both ends, good flavor, drying rate of 25%-26%, good early maturity, suitable for early planting and early harvest, and decline in quality after October harvest. 3. Seedling raising: early-maturing varieties should adopt greenhouse + small arch greenhouse + plastic film three-layer heat preservation to raise seedlings. After early emergence, plastic film mulching is used to supply the market, while conventional cultivation can use small arch shed and plastic film two-layer thermal insulation to raise seedlings. The nursery bed is about 1.0m wide and deep 15~20cm. The bottom of the bed is covered with organic fertilizer and then watered and covered with soil. The selection of seed potato is required to have the typical characteristics of this variety, no diseases and insect pests, 100g and 250g. The planting density is about 3cm between tubers. After the seed potatoes are arranged, cover the soil with a thickness of 2~3cm, which should not exceed 5cm, so as not to affect the emergence of seedlings. Remove the plastic film when 60% of the potatoes sprout. When the temperature is more than 20 ℃ on a sunny day, ventilation should be opened at both ends of the arch greenhouse film and the greenhouse film to prevent high temperature from burning seedlings, and the bed temperature should be kept at 25: 30 ℃. The humidity should be based on the dry and wet soil of the bed. When potato seedlings grow 20~25cm and have 6 or 8 intact leaves, they can be cut and planted in the field. 4. Soil preparation and fertilization: soil preparation should be carried out on a sunny day, and the soil should be broken and broken. After leveling, the fertilizer strip is applied at the bottom of the ridge, the distance from the ridge is 80cm, and the height of the ridge is about 20cm. Special organic compound fertilizer can be used for fertilizer. when the planting area is large, soil N, P, K and organic matter should be determined. In the south, soil pH value, hydrolyzed nitrogen 40~60mg/kg, available phosphorus 20mg/kg, available potassium 100mg/kg, organic matter 1% and pH5.0~6.5 should be determined. According to the soil fertility level and the fertilizer requirement characteristics of sweet potato, prepare N, P, K and organic fertilizer. The use of common compound fertilizer is not recommended. 5. Planting: the seedlings can be cut and planted in the field when the average temperature is more than 10 ℃. Because of the low temperature in the early stage (from late April to mid-May), plastic film mulching can be used. When planting, the four nodes were inserted horizontally or obliquely into the soil, the two leaves were exposed to the ground in case of drought, and the rest of the leaves were buried in the soil, so as to make the potato seedlings survive and spread evenly, increase the commodity rate and yield, plant density 4000 plants / 667m2, plant spacing 20cm. 6. Field management: sweet potato diseases mainly include black spot and soft rot, and underground pests mainly include grubs and golden needle insects. The selection of loose Xinkai red and yellow soil or the implementation of flood-drought rotation can effectively avoid diseases and underground pests. The main aboveground pests are Spodoptera litura and sweet potato wheat moth, which are damaged from July to September. In the 1-2-year-old stage of the pest, 5% Yitaibao or 5% carbazem 1000 × 1500 times solution is applied to control the pests. After planting, Acetochlor was used for chemical weeding, and in the middle stage of sweet potato growth, artificial weeding was carried out for 1 or 2 times, so that there was no need to turn the vine. 7. Harvest: there is no obvious ripening period of sweet potato. The harvest time should be determined by field sampling, 10 plants are dug continuously, and the yield and commodity potato rate are determined. When the commodity rate reaches 65% to 70%, it can be harvested. Heart incense can be harvested 90 days after planting, and the earliest harvest time is in late July. The harvest time can be determined according to the local climate characteristics and market demand. Collect it before the frost at the latest. It should be noted that sweet potatoes can not be harvested on rainy days, lest there is more soil on the potato pieces, affecting the appearance of the goods; when harvesting, they should be dug, loaded, transported and unloaded lightly to prevent bruising of potato skins and pieces, and harvested and stored separately according to varieties. If the temperature reaches 32 ℃ during harvest, sweet potatoes should be sent into the house within 2 hours so as not to burn the skin and affect the appearance and storability. 8. Transport, storage: use plastic turnover boxes to transport into the warehouse. Short-distance transport to prevent the sun, rain, long-distance transport to prevent freezing, heat preservation or cooling. The optimum storage temperature of sweet potato is 10: 15 ℃, the relative humidity is 85% and 90%, pay attention to prevent frostbite and reduce water evaporation, pay attention to ventilation and heat dissipation, prevent pollution of toxic and harmful substances, and prevent injury caused by extrusion.