Yam: Curly spherical buds will grow between the leaf axils of its stems. It is an aerial tuber, specifically called Lingyuzi, also known as yam eggs. The skin of yam eggs is earthy yellow and the flesh is white. It tastes sweet and smooth when cooked, and tastes the same as stems. The granular shape is like sheep dung eggs. Jin writers call themselves yam egg pie because they are yam eggs instead of potatoes.
The name of yam is Sushu, which is the name of the clan in the Tang Dynasty. It is taboo to change the name of yam into potato medicine. In the Song Dynasty, Emperor Shenzong of the Song Dynasty tabooed potato and replaced it with yam. The name of sweet potato is sweet potato. "The Classic of Mountains and Seas" says: "Jingshan looks to the north of Shaoze, and there are many sweet potato grass there." "Compendium of Materia Medica" contains: "The seedlings spread in April, with purple stems and green leaves, and the leaves have three tips, five or six The moon blossoms into ears, light red. "On the way to Qizhou Bolian Temple, I saw a yam climbing on a water bamboo pole. Its stems and leaves were as delicate as an artistic brushwork. "Compendium of Materia Medica" records: yam has ears, eyes, intelligence, lightens the body, prevents hunger, and prolongs life. It is mainly used to treat wind in the head and face, dizziness, low breath, relieve back pain, cure fatigue, replenish the five internal organs, and remove irritability and heat. In addition, it can replenish the five labors and seven injuries, open up the heart holes, strengthen the muscles and bones, cure semen and forgetfulness, replenish kidney qi, strengthen the spleen and stomach, and moisturize the skin.
[Origin Distribution] It is mainly produced in Henan, Shanxi, Shaanxi and other provinces; it is also cultivated in Shandong, Hebei, Zhejiang, Hunan, Sichuan, Yunnan, Guizhou, Guangxi and other places.
Dioscorea opposita Thunb (D. batatas. Decne) (see Figure 8-6), also known as yam, yam, and vegetable yam, is a perennial twining herb of the Dioscoreaceae family. The roots are used as medicine. Mainly produced in Henan , Shanxi, Shaanxi and other provinces; it is also cultivated in Shandong, Hebei, Zhejiang, Hunan, Sichuan, Yunnan, Guizhou, Guangxi and other places. The tubers contain saponins, mannan, phytic acid, allantoin, choline, dopamine, and yam. Vitamin I, arginine, amylase, protein, fat, starch and iodine, etc. It is sweet in taste and neutral in nature. It has the functions of strengthening the spleen and relieving diarrhea, nourishing the lungs and nourishing the kidneys. It is used for chronic diarrhea, chronic enteritis and lung deficiency. Cough and asthma, chronic nephritis, pityriasis, spermatorrhea, leucorrhea and other diseases.
(1) Plant characteristics and species introduction
1. Plant characteristics: Yam is a perennial herb with long stems. It can reach 2 to 3 meters. The roots are upright, fleshy, rod-shaped, 30 to 35 cm long, with few branches and many fibrous roots. The leaves are opposite and the shape of the leaves is variable, often heart-shaped or arrow-shaped. , palmate leaves with 6 to 9 veins, and aerial tubers (called Lingyuzi, also called yam beans and yam eggs) between the leaf axils, which can be used for reproduction or consumption. The flowers are unisexual, dioecious, with spadix inflorescences, male flowers upright, and female flowers. The order is drooping. The capsule is triangular and wing-shaped. The seeds are broad-winged and nearly oval (Figure 8-6). 2. Variety introduction: Botanically, yam includes many species. , there are medicinal and vegetable seeds, and there are three main types cultivated in my country: one is domestic yam, also called common yam, which is native to my country and is the northernmost species in the Dioscoreaceae family. It is characterized by rounded stems and no ribs; The second is field potato, also called big potato. It is native to India. It is cultivated more in southern my country and less in northern China. It is the species with the oldest cultivation history and the largest area. It is characterized by square stems, ribbed wings, and tubers up to 30 kilograms. ; Third, it is wildly distributed in South my country, East China and other places. The roots are cylindrical and about 40 cm long.
(2) Biological characteristics
1. Growth and development of yam in the ground temperature. When the temperature reaches 13°C or above, the seedlings can germinate and emerge. After planting, they will sprout first and then take root; when they are planted, they will first take root and then take root. From early July to early August, aerial tubers will appear in the leaf axils. The period from mid-to-late September is the period of rapid growth and development of underground stems. After the frost, the stems and leaves wilt and the roots enter the dormant period.
2. Requirements for environmental conditions: Yams do not have strict requirements for climate conditions and like warm weather. Cold-resistant. It can grow well in sunny and warm plains or hilly areas. Sichuan can still grow normally and obtain medium yields when planted in mountains with an altitude of 1,600 meters. Since yam is a deep-rooted plant, it requires deep soil and good drainage. Yams can be planted in loose and fertile sandy loam soil with a pH of 6.5 to 7.5. Yams have strong fertilizer absorption and require a lot of potassium fertilizer.
(3) Cultivation techniques
1. For land preparation, it is better to choose sandy loam with deep soil, loose fertile soil, sunny location, smooth drainage, and appropriate acidity and alkali.
The roots of yam are relatively deep in the soil, and some can reach 1 meter, so the land needs deep plowing.
Plow the land deeply in winter, and apply basal fertilizer before planting the next year. Apply 75 kilograms of manure, compost, etc. per hectare, then plow the soil to a depth of about 50 centimeters, and then rake it flat. In the south, where there is more rain, a 1.3-meter-high border should be opened before planting to facilitate drainage. In the north, where there is less rain, a 10- to 15-centimeter-high border should be created immediately after planting 4 to 5 rows to facilitate irrigation. Ridge planting is also used in the north. Some people think that different cultivation methods have an impact on yield. For large-area cultivation, planting with shallow ditches has higher yields than planting with drilling methods.
2. Propagation method
(1) Faucet propagation The faucet is also called yam mouth, which is the upper part of the rhizome when yam is harvested. It is the main propagation material for yam field production. Each yam plant only produces one faucet every year, and there are various losses, so the number of faucets is getting smaller and smaller year by year, especially as the faucets become thinner and longer during cultivation, the tissue ages, and the yield decreases, so it can no longer be used as propagation material. Replace with a new faucet bred from scraps.
(2) Lingyuzi propagation Lingyuzi sowing is carried out in April. Before sowing, the stored seeds should be sorted to select the ones that are fat, plump, neat in shape, free of damage and dryness, with white outer skin and green inner skin. Sow in furrows with row spacing of 20 to 25 cm, plant to plant spacing of about 7 to 10 cm, and covering with soil of about 6 cm. Field management is as usual. The grown dragon head can be used for planting the following spring.
In field cultivation, the yield of dragon heads cultivated from leftover seeds is average in the first year, the highest in the second year, and then decreases year by year. Therefore, in the fourth and fifth years, all faucets need to be updated, which means that the faucets cultivated by Lingyuzi are often used in production for no more than 5 years.
3. Field management
(1) Scaffolding to induce vines: Yam stems are long, slender and fragile, and are easily broken by the wind. The height of the seedlings is about 20 cm, so a scaffolding should be set up to induce the vines to twine and grow upward. The scaffolding method is " The herringbone frame is stronger, and this method has better ventilation and light transmission.
(2) Topdress three fertilizers. Before and after the yam is put on the shelf, apply "seedling-strengthening fertilizer" in combination with shallow cultivating to promote root growth and seedling growth. After the yam vines are halfway up the trellis, apply a "long-potato fertilizer" once between the rows to promote the seedlings to grow vigorously; before and after the summer solstice, apply a "long-potato fertilizer" to the yam, at a rate of 37,500-45,000 kilograms per hectare.
(3) Reasonable drainage and irrigation. In the north, there is generally drought in the early stage. Pay attention to irrigation during the seedling stage. Timely drainage is required when the rainy season starts from July to August. In the south, it is generally rainy in the early stage, so attention should be paid to drainage during the seedling stage.
(4) Pruning to control seedlings. After the yam seedlings are put on the shelves, if side branches appear at the base, they should be removed in time to facilitate concentration of nutrients and increase root tuber yield.
4. Pest and disease control
(1) Anthracnose (Gloeosporium pestis Massee) damages stems and leaves. Harvest time occurs from mid-June. Often causes stems to wither and leaves to fall. Prevention and control measures: clear the garden and burn the diseased plants to reduce the source of overwintering bacteria; soak the planting in 1:1:150 times Bordeaux mixture for 4 minutes to eliminate the bacteria; spray 65% ??zinc wettable powder 500 times at the beginning of the growth period Or 50% sterile wettable powder 800 to 1000 times liquid.
(2) Brown spot disease (Cylyndrosporium dioscoreae Miyabe et lto.), also called leaf spot disease, damages the leaves and begins to appear in late July. Prevention and control methods: clean the fields, treat diseased leaves of residual plants; rotate crops; spray control with 58% mancozeb wettable powder 1000 times during the onset period.
(3) Rust damages the leaves, occurs from June to August, and is severe in autumn. Use 500 times 50% carbendazim wettable powder, spray once every 7 days, and apply 3 to 4 times continuously.
(4) Root rot is a bacterial disease that damages adult plants that are two years old or above. The disease begins in May and peaks in July and August. Crop rotation or 500 times of 65% Zinc wettable powder spraying can be used Or root irrigation.
(5) The yam sawfly (Senoclidea decorus Konow) is a specialized pest that damages yam. In the early stages of pest occurrence, 90% trichlorfon original drug can be used to control the pests in 1,000 times solution.
(4) Harvesting and processing
Harvest can be done when the above-ground parts die in October of the year of planting.
First, pull up the pillars and vines together, shake off any loose ends on the vines, and collect the loose ends that fall on the ground. Starting from one end of the border, dig a deep trench and carefully dig out the yam tuber roots one by one to prevent breakage; care should also be taken to protect the faucet from damage. After digging, break off the faucets used for seeding on the spot and transport them back separately. If the rainwater flows smoothly, 3,750-7,500 kilograms of leftover seeds and 18,000-33,000 kilograms of fresh yam can be harvested per hectare.
After the roots are transported back, they should be processed in time. Wash the tubers, soak them in water, and scrape off the skin with a bamboo knife or glass piece. After scraping the skin, put it into a fumigation stove and fumigate it with sulfur. Use 0.5 kilograms of sulfur for every 100 kilograms of fresh yam and smoke it for 20 to 30 hours. When the tubers become soft, take them out and dry them in the sun or on the kang until they are completely dry, which is called tops. The appropriate drying temperature is 40~50℃. In the south, 6 kilograms of fresh yam can yield 1 kilogram of tops; in the north, 3 to 4 kilograms of fresh yam can yield 1 kilogram of tops. Generally, the yield of tops per hectare is 3,000 to 3,750 kilograms, and high yielders can produce 5,250 to 6,000 kilograms.
Key points of yam cultivation technology
1. Germination of seed potatoes
Select disease-free and healthy yam or leftover seeds with a diameter of more than 1.5 cm for seeding. Before sowing, Use wet sand or fine soil to accelerate germination in an environment of about 25 degrees Celsius, and germinate after 2 to 3 weeks.
2. Sowing
Yams are generally planted in spring and can be sown when the local temperature is 10 degrees Celsius. Single-row drills are planted in the center of the border, while double-row drills are planted in trenches on both sides of the border with a trench depth of 10 cm. After fertilization, the seed potatoes are placed flat in the trench with a plant spacing of 15 to 20 cm, and then covered with soil. If the soil moisture is insufficient, water first and then sow.
3. Stretching and pruning
Yam is a vine plant, and the young stems are fragile and easy to break. Therefore, support should be set up as soon as possible when the seedlings are about 30 cm high to promote stem vines. Robust growth. When the plant grows vigorously and has many side branches, remove the side vines at the base to reduce nutrient consumption and increase wind and light penetration. When a large number of leftover seeds occur, some should be removed to avoid consuming too much nutrients and affecting the growth of the tuber.
4. Fertilizer and water management
Yams have shallow roots, so fertilizers should be applied to the upper layer of the tillage layer. Stem fertilizers are mainly organic fertilizers. Generally, 100 kilograms of cake fertilizer, 6,000 kilograms of gray fertilizer, 5,000 kilograms of manure, and 30 kilograms of carbon ammonia are applied per 666.7 square meters. In the early stages of tuber growth and at the peak of tuber growth, top dressing can be applied. Human excrement and cake fertilizer can be used, and no more fertilizer is applied after September. If there is a drought during the peak growth period of the tubers, irrigation should be strengthened and carried out in the evening. The depth of irrigation should only reach half a ditch of water. When there is too much rain, water should be drained in time.
5. Harvesting and saving seeds
Start harvesting when the stems and leaves are all withered. Harvesting too early will result in lower yields. In areas where the winter is not very cold, the tubers can be left in the soil. , collected and supplied at any time. Seed potatoes are harvested before frost, and the tissue is not abundant enough when harvested too early. For seed potatoes, high-yielding plants with large pedicles and smooth skin should be selected with the characteristics of this variety. Do not damage the potato skin when digging. Seed potatoes can be hung with the base of the plant in a ventilated place or beside the stove for smoke, or they can be hidden in the cellar with sand.
Habits of yam
After years of practice, the author has concluded that yam has a strange temperament of "six joys and six taboos".
Like "strong" soil and fields. Brown soil and loess are better. Generally, rice is planted in the first year, and then wheat is planted as interplanting. Avoid vegetable garden soil and soaking soil.
I like planting at the right time. Winter is the dormant period of yams, and it is necessary to wait until early April after the yams have sprouted eyes before planting. Avoid early planting, as the wounds of early planting are easily infected with germs and will cause many tree losses.
Prefers fertilizers rich in phosphorus and potassium. Such as vegetable cake, compound fertilizer, manure, plant ash, etc. Yams generally use base fertilizer as the main fertilizer, and top dressing should be compound fertilizer, vegetable cake, etc. Avoid applying immature soil fertilizers, pig manure, etc.
Likes dryness. Yams should be cultivated in narrow fields and deep ditches beside mountains. Avoid fields with high water content and shallow ditches.
Likes cold soil and resists drought. Although it is drought tolerant, it still needs to resist drought if there is no rain for dozens of days. It is advisable to irrigate in cold soil ditches in the latter half of the night with a moderate amount of water. Avoid high temperatures and drought during the day, as this can cause physiological disorders in Ayahuasca.
It likes to "cover" grass. Generally, after the budding crops are harvested, the yam is lightly hoeed once, and then a bracket is inserted to allow the vines to stand. Cover the compartment surface with thatch, wheat, and rapeseed shells. Avoid weeding too much, because weeding will loosen the soil and increase the water content; if it is not suitable for its dry habit, it will easily rot the roots of the ayahuasca.
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