Scientific name: Dioscorea opposita

Other names: Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, Sweet Potato, Sweet Potato and Yuyan.

Smell: (root) sweet, warm, flat and nontoxic.

Distribution of origin

It is distributed in North China, Northwest China and various provinces in the Yangtze River Basin.

The planter calls it domestic yam, and the wild yam; Chinese herbal medicines are called Dioscorea opposita, Dioscorea opposita and so on.

Because of its rich nutrition, it has been regarded as a good tonic with good quality and low price since ancient times. It can be used as a staple food, a vegetable, and a snack such as candied haws.

China is mainly produced in Bo 'ai, Qinyang, Wuzhi, wen county and other places in Henan Province, and it is also cultivated in Hebei, Shanxi, Shandong, Central South and Southwest China. After the stems and leaves wither in winter, dig, cut off the roots, wash and dry.

There are two main types of yam cultivated in China: common yam and sweet potato. Ordinary yam tubers are smaller, among which "Jiaoban Potato" from Sichuan and other places, Huai Yam from Huai County, Shanxi Province, and Huai Yam from Nancheng, Jianghan are the most famous.

morphological character

The rhizome is thick and straight, and the length can reach 1 m. Leaves alternate, opposite to the middle or above, rare or 3 whorls, often with bulbils (Reiyoshi) between the axils, with varied leaf shapes, ranging from triangular ovoid to triangular broadly ovoid, often 3-lobed to deeply lobed. The flowers are dioecious, very small, green and white, all in spikes, the male inflorescence is erect, and the female inflorescence is below. Capsule has 3 wings.

Growth habit

Cold-resistant, light-loving. It is suitable to grow in loam with good drainage and loose fertility. Avoid flooding. Underground stems are cylindrical, fleshy and hypertrophy. The stem is cylindrical, and egg-shaped bulbils are inserted between the axils of leaves. Leaf blade triangular-ovate to triangular-broadly ovate, base halberd-shaped. The male inflorescence is spike-shaped, not pendulous, the long axis is mostly zigzag, the male flowers are nearly sessile, the bracts are triangular-ovate, shorter than the perianth, the perianth segments are 6, ovate, and stamens are 6, developing; The female inflorescence is similar to the male inflorescence, and the ovary stigma is 3-lobed. Capsule has 3 wings, the fruit wings are several times as long as wide, with short stalks, and 2 seeds in each room, which are placed in the center; The seeds are ovoid, surrounded by chestnut shell-colored thin wings, which are about 6 mm wide and unequal in width. The flowering period is June-August, and the fruiting period is August-1October.

Garden use

Dioscorea opposita can be used as a vertical greening material for climbing fences in gardens. Tubers are often eaten as vegetables. Tubers (yam) and bulbils (Reiyoshi) can be used for medicine and can strengthen the spleen.

Saponin extracted from Dioscorea zingiberensis is the starting material of steroid hormones. It can be used to synthesize and produce more than 60 kinds of 6-grade steroid hormone drugs with anti-inflammatory, analgesic, anesthetic and contraceptive functions, which are widely used to treat many diseases such as heart disease, anti-tumor, rheumatoid disease and serious infection, with thorough treatment, no recurrence and no toxic side effects. Dioscorea zingiberensis is a wild plant. With the wide application of saponin in medicine, the wild resources are decreasing year by year, which is far from meeting the market demand. In Kaixian County, improved varieties of Dioscorea zingiberensis were introduced from 200 1 year for artificial cultivation, and now it has grown to more than 2,000 mu, and in 2004 it can grow to 1 10,000 mu. There are sufficient pre-resources of Dioscorea zingiberensis, so it is necessary to invest and introduce advanced processing technology and equipment, and then process the hydrolysate on the spot to extract saponin. In order to develop Dioscorea zingiberensis as an industry, it is necessary to invest in a leading processing enterprise to promote the development of Dioscorea zingiberensis.

cultivation techniques

Variety selection

At present, the main varieties of yam planted are fine-wool long yam, Ermao yam and Japanese "Daiwa taro" yam. Fine-wool long yam and Ermao yam belong to long-column varieties of common yam. Japanese yam is a variety with strong adaptability, good quality, strong disease resistance, high yield and promising development. Peng Juntian is the Japanese "Yamato taro" yam variety.

Selecting land, ditching and leveling the border

The planting of yam should try to avoid repeated cropping, generally rotate once every three years, and avoid planting peanuts and red taro stubble. It is better to choose a plot with deep, loose and fertile soil layer, and the soil quality should be consistent from top to bottom. The lower layer has sticky soil layer and Baishagang soil layer, which should be completely broken when trenching. At least1~1.2m soil layer can not have interlayer such as clay, soil and sand. Otherwise, it will affect the appearance and quality of tuber. The soil should be neutral. At present, mechanical ditching is generally used. Yam cultivation should be in the north-south direction, and it can be planted in two rows or in a single row (you can widen the row spacing according to the needs of individual plots). When planting in two rows, the large row spacing1.7 ~1.8 meters, the small row spacing (the row spacing of yam twice in the ditch) is 40 cm, the plant spacing is 20 ~ 25 cm, and the ditch depth is 85 ~/. Leveling shall be carried out during land preparation and border leveling to prevent uneven watering. In addition, drainage design should be done well to ensure that there is no water in the field border. When planting in a single row, the row spacing is 80 ~100 cm, the ditch width is 30 cm, the ditch depth is 90 ~100 cm, and the plant spacing is 20 ~ 25 cm.

Suitable sowing time

Generally, Chinese yam is planted in greenhouse around New Year's Day. Generally, it is required that the ground temperature of 5cm on the surface should be stable over 9 ~10℃. Dry the yam seedlings in the air before sowing, which can activate the seed potatoes and play a role in sterilization and high germination rate. If yam stems are cut off to make seed potatoes, lime powder can be dipped in the incision in time to disinfect it. When planting seeds, the buds should be planted under a piece with buds, and the buds should be planted under a piece with a general size, so that the buds will be uniform. In addition, the seeds should be soaked for 3-5 minutes with 500 times of carbendazim, 1000 times of triadimefon and 72% of chlorothalonil 1000 times, and then the seeds can be planted after drying.

Yam is mainly made of organic fertilizer (such as decomposed cake fertilizer, chicken manure, duck manure or human and animal manure, etc.), supplemented by inorganic fertilizer. Generally, the dosage can be 2000 ~ 4000 kg per mu, plus 40 ~ 60 kg of high-potassium compound fertilizer, or 200 ~ 300 kg of special bio-organic fertilizer for yam, which is fully and evenly mixed with soil to prevent seedling burning.

field management

1, shallow topdressing. If the base fertilizer is used more, less or no topdressing is needed. In order to ensure the high yield of yam, topdressing is usually 2 ~ 3 times, topdressing is once when the aboveground plants grow to about 1 m, and topdressing is once every other week or so, and then it can be done for 3 times. In the swelling stage of Chinese yam, multi-element compound fertilizer with high phosphorus and potassium content is the main ingredient (the demand ratio of Chinese yam to nitrogen, phosphorus and potassium is1.5: 2: 5), and it is about 30 kg per mu, so it is best to apply it by flushing. 0.2% potassium dihydrogen phosphate and 1% urea can be sprayed on the leaves in the late growth stage to prevent premature aging. In particular, it should be noted that the absorption root system of yam is shallow, occurs early, and extends horizontally. When fertilizing, shallow soil layer should be applied for yam root system absorption.

2, the frame should be firm. Chajia and weeding yam are covered with 6 ~10 cm of floating soil after sowing, then sprayed with "special herbicide for yam"150 ~ 200 g of water 100 kg evenly, then covered with plastic film, and erected in time after seedling emergence. The height of the frame is about 2 meters, and the front side is in a "human" shape, and the sides are diagonally crossed.

3. Water skillfully. Yam is afraid of waterlogging and should not be too dry. If it is too dry, it will seriously affect the swelling of yam, especially in the tuber swelling period, which lasts from mid-April to late May. During this period, it is usually watered once every 10 day, and after late May, it should be watered appropriately according to the soil moisture.

4, pest control should keep up. Pests and diseases are more serious in the continuous cropping plots, and the plots planted in the first year are less serious. After the yam vines are put on the shelves, spraying drugs is started to control them.

The main disease of yam is anthracnose, which belongs to fungal disease. The common people call it defoliation, which shows that the leaves are yellow in the early stage, and the leaves appear small spots, and finally the stems fall off. This disease is mainly prevented. Do a good job in crop rotation, choose disease-free potatoes, soak the seeds with 25% carbendazim powder 500 times before sowing for 25-30 minutes for disinfection, and strengthen field management after cultivation to enhance plant disease resistance.

Generally, 70% mancozeb 500 ~ 600 times solution and 50% thiophanate methyl 700 ~ 800 times solution can be sprayed alternately at the initial stage of the disease. When the disease is severe, the special formula pesticide for Japanese "Daiwa taro" yam can be sprayed every 7 ~10 days at the initial stage of the disease, and it can be sprayed continuously for 2 ~ 3 times.

harvest

The harvest period of yam in the normal open field is very long. From August 20th to April and May of the following year, yam does not rot or deteriorate in the ground. Generally, it is a concentrated harvest period around first frost for the Spring Festival market. But the yam in greenhouse is different. Because the harvest time is around June 20th, the yam itself has low starch content and high moisture content, so it can't be stored for a long time. The yam in greenhouse should be sold in time after harvest. In addition, due to factors such as planting scale, the yam in greenhouse is now mostly dug manually. Because the yam skin is very thin, it is necessary to prevent mechanical damage when digging yam, and the yam is piled with mud foreskin for sale.

cure

(Note: It is the rhizome of Dioscorea opposita of Dioscoreaceae. )

1, heart distension, hand and foot syncope, not thinking about diet. Stir-fry Dioscorea zingiberensis for half a lifetime. Two yuan each time, the rice soup will be closed. Take it twice a day.

2, forbidden mouth dysentery. The treatment is the same as above.

3. More urine. Divide yam (boiled with alum) and Poria into powder. It costs two yuan each time, and the water is delivered.

4, phlegm wind and shortness of breath. Use half a bowl of raw yam (mashed), add half a bowl of sugarcane juice, mix well, and drink at one time.

5, the spleen and stomach are weak, not thinking about diet. Use one or two of Dioscorea zingiberensis and Atractylodes macrocephala, seven and a half dollars of ginseng, grind them into powder, add water and paste to make balls as big as adzuki beans. Take forty to fifty pills each time, and send rice soup.

6, damp and heat deficiency. Divide Dioscorea opposita and Rhizoma Atractylodis equally, and add rice to make meatball rice soup for service.

7, swollen poison at the beginning. Divide yam, castor bean and glutinous rice with mud into equal parts, soak them in water, grind them and spread them.

8, hand and foot frostbite. There is a piece of yam, which is ground and applied.

Roots are used as medicine to nourish and strengthen the body, treat spleen and stomach deficiency, etc., and can also be used as non-staple food and raw materials for brewing wine.

Dioscorea zingiberensis, a plant of Dioscoreaceae, has a horizontal rhizome and looks like ginger, also known as Dioscorea zingiberensis. Take root as medicine.

The rhizome of Dioscorea zingiberensis is mainly used to extract diosgenin, which is a good raw material for synthesizing adrenocortical drugs. At present, 60 to 70 kinds of steroid hormone drugs are produced from diosgenin at home and abroad, which are widely used to treat cancer, cardiovascular and cerebrovascular diseases, respiratory diseases, contraceptives and so on.

Nutritional analysis

1. Spleen, stomach and digestion:

Yam contains amylase, polyphenol oxidase and other substances, which is beneficial to the digestion and absorption function of the spleen and stomach. It is a dual-purpose product of medicine and food that blindly tonifies the spleen and stomach. Both spleen yang deficiency and stomach yin deficiency can be eaten. Clinically, it is commonly used to treat spleen and stomach weakness, anorexia, fatigue, diarrhea and other diseases;

2. Nourishing kidney and benefiting essence:

Yam contains a variety of nutrients, which have the functions of strengthening the body, nourishing the kidney and benefiting essence. Generally, symptoms such as nocturnal emission due to kidney deficiency, frequent urination, etc. can be taken;

3. Benefiting lung and relieving cough:

Yam contains saponin and mucilage, which has lubricating and moistening effects, so it can benefit lung qi, nourish lung yin and treat lung deficiency, phlegm and cough for a long time;

4. Reduce blood sugar:

Yam contains mucin, which has the function of lowering blood sugar, can be used to treat diabetes, and is a good diet for diabetics.

5. prolong life:

Yam contains a lot of mucin, vitamins and trace elements, which can effectively prevent the deposition of blood lipids on the blood vessel wall, prevent heart disease, and achieve the effects of benefiting the mind, calming the nerves and prolonging life.

6. Anti-hepatic coma

In recent years, it has been found that yam has sedative effect and can be used to resist hepatic coma.

Edible crowd

It can be eaten by the general population.

1. Suitable for patients with diabetes, abdominal distension, weakness after illness, chronic nephritis and long-term diarrhea;

2. Yam has astringent effect, so people with dry stools should not eat it; In addition, those who are evil should not eat yam.

Food phase grams

Yam and kansui should not be eaten together; Nor should it be taken with alkaline drugs.

Production instruction

1. yam should be soaked in salt water immediately after slicing to prevent oxidation and blackening.

2. When fresh yam is cut, there will be mucus, which is easy to slide and hurt your hand. You can wash it with water and a little vinegar first, which can reduce mucus.

3. Yam is delicate in texture and sweet in taste. However, the skin of yam is easy to cause skin allergy, so it is best to peel it, and don't touch your hands after peeling yam. Wash your hands several times immediately, otherwise you will scratch and itch.

4. Good yam skin is harmless, with mucus, white fault, more mucus and less water. The skin can be fried fresh, or dried in the sun to make soup or porridge. Peel and eat, so as to avoid abnormal taste such as hemp and thorns.

5. Fresh yam is mostly used for fatigue cough and diabetes, and fried cooked food is used to treat spleen and stomach and kidney deficiency.

Dietetic therapy

Yam is sweet and flat, and enters the lung, spleen and kidney meridians; Not dry or greasy;

Has the effects of invigorating spleen and lung, invigorating stomach and kidney, strengthening kidney and essence, improving hearing and eyesight, helping five internal organs, strengthening bones and muscles, calming nerves, and prolonging life;

Indications are spleen and stomach weakness, listlessness, anorexia, chronic diarrhea, lung qi deficiency and dryness, phlegm and cough, kidney qi deficiency, soreness of waist and knees, weakness of lower limbs, thirst and frequent urination, nocturnal emission and premature ejaculation, leukorrhagia, skin swelling and obesity.

Other related

"Compendium of Materia Medica" summarizes five functions: benefiting kidney qi, strengthening spleen and stomach, stopping diarrhea, resolving phlegm and saliva, moistening skin. Cooking porridge with yam or taking it after cooking with crystal sugar has curative effects on chronic diseases such as poor health, enteritis and kidney deficiency.

1. tonify spleen and stomach: treat spleen and stomach weakness, diarrhea, body fatigue, anorexia and sweating.

2. Benefiting lung and nourishing kidney: This product is cold and not dry, and it tastes sweet and moist. It can treat thirst, nocturnal emission and leukorrhagia due to lung and kidney deficiency.

Cultivation of Chinese yam

First, it is suitable to grow in the cavity tube. In addition to hole tube cultivation, reasonable fertilization or complete application of decomposed organic fertilizer can improve the yield and quality of yam. Organic fertilizer can improve soil composition, provide sufficient nutrition, prolong the release and utilization time of nutrients, enhance root respiration and provide sufficient water. Yam plants that have just begun to grow new buds come from their mother potatoes. Yams that enter the early stage of development need more nitrogen fertilizer to promote their growth, and potassium fertilizer is particularly important at the beginning of potato block formation. It seems that Chinese yam can easily absorb phosphate fertilizer from soil. In addition, if magnesium fertilizer can be added, it will also contribute to the increase of yield.

The second type: to cultivate yam, sandy soil with fertile soil, deep soil layer, strong water and fertility conservation, good ventilation and convenient irrigation and drainage must be turned over 35-45 cm. When turning over the land deeply, the topsoil layer of 20-30 cm above should be turned aside first, and then it should be turned over to 35-45 cm. It is forbidden to turn over the soil layer. After the land is deeply ploughed, a cultivation ditch is formed, and base fertilizer can be applied into the cultivation ditch. 20 kg of superphosphate, 3,000 kg of decomposed organic fertilizer and 200-300 kg of plant ash are applied to the base fertilizer. When applying fertilizer, the bottom of the planting ditch can be filled with the original topsoil with a thickness of15cm, then the base fertilizer is applied on the soil layer, and finally the soil is covered with15cm.

Top dressing of yam is mainly in the middle and late stage of growth, and less fertilizer is needed in the early stage. Apply 20% human excrement and urine fertilizer 1 time after the yam emerges neatly, and then apply 1 time every 20-30 days. Fertilization can be done by digging 1 6-10 cm deep fertilization ditch 30 cm away from the plant, and applying 700-1000 kg of human excrement and urine per mu. When underground tubers enter the peak period of vigorous growth, they should be topdressing again 1 time. 20-30 kilograms of compound fertilizer and 40-60 kilograms of cake fertilizer are applied in holes or ditches, and the soil is covered after fertilization to ensure that the tubers are elongated and expanded with sufficient nutrients. Whether or not topdressing will be determined later depending on the plant growth.

It is usually found in the food market.