Yam is a dry root of the yam of the yam family, which is a commonly used traditional Chinese medicine. Originally published in "Shen Nong's Herbal Classic", formerly known as "yellow yam", the name "yam" was first seen in "Materia Medica". Yam is flat, sweet, into the spleen, stomach, lung, kidney, can make up the spleen and stomach, benefit lung and kidney, attending spleen and stomach weakness, eating less sugar, long-term diarrhea, lung deficiency cough, kidney deficiency, low back pain, slippery essence.
Yam is a perennial entwined herb with a short stem, erect roots, thick meat, cylindrical stick shape, length of up to 1 meter, diameter of 2-7 cm, outer skin gray-brown, most of the roots, crisp, white section Sticky. Stems slender, usually purple, ribbed, smooth and glabrous. The leaves are opposite or three-piece, and the leaves of the leaves are often "zero surplus", commonly known as "yam bean." The shape of the leaf is varied, triangular-oval or triangular-shaped, broadly ovate, 3.5-7 cm long, usually three-lobed, laterally lobed rounded, apex acuminate, and 7-9 veins from leaf base. Flowering from June to August, flowers are dioecious, flowers are yellow-green, all spikes, male inflorescences erect, female inflorescences drooping, flowers milky white. The seeds are oblate and have wide wings.
The yam is not strict with the climate, and it is generally not cultivated in areas that are too cold, but the choice of soil is stricter. Since yam is a deep-cultivated plant, it is advisable to choose a sandy loam with deep, fertile, loose and well-drained soil.
In the area where the yam is infested, it cannot be continuous. After two years of planting, it must be planted with other crops for one year to avoid lack of seedlings and ridges. Because yam is easy to infect the virus, it is especially important not to rotate with a virus crop. In addition, the land with nodulopathy is not suitable for cultivation. Due to infection, the roots of yam roots are poorly grown and difficult to process, affecting yield and quality.
First, there are many cultivars for breeding yam, and good varieties should be selected for breeding. Propagation materials can be used with bead buds and reed heads. The bead bud is mainly used for seedling raising, providing reed head for the next year's production; the reed head is used to produce yam, and the reed head is easy to cause degradation after continuous use for many years, so it needs to be updated once every 2-3 years.
Bead bud reproduction: When the yam stem leaves are sallow in late October, the buds are harvested, and the large and round beads buds without damage and pests are selected, and they are stored in the house with dry sand to prevent freezing damage in the winter; in the spring of the next year, the climate warms up and is used as a cockroach. In the middle and the middle of the month, the row spacing is 18~24cm, 2-3 seeds per 10cm, and the planting depth is 6-9cm. After planting, the seedlings can be unearthed. After half a month, the seedlings can be unearthed. Planted, also known as round head.
Reed head reproduction: When digging yam in winter, choose the yam with a short neck, full of buds, and no disease and insects. Choose a length of about 12-18 cm, and the wound of 4-5 angels will heal and store it with sand. The storage method is to first lay a layer of river sand in the house, about 15 cm thick, and then lay a layer of reed head, 15 cm thick, and then cover the sand 9-12 cm, with this layer of sand, a layer of reed, when the pile When it is 60-90 cm high, cover the river sand, and finally cover the grass to pass the winter. However, the room temperature should not be too high, generally about 5 ° C is good. When the spring is frozen, it can be planted without frost at night.
Second, when planting and planting, apply enough base fertilizer, deep turn 24-30 cm, squat fine and flat, made flat. The planting method is divided into single row and double row, the row spacing is 30-45 cm, the plant spacing is 15-18 cm, the ditch is planted, the ditch depth is 15 cm, the width is 18 cm, the reed head is placed in the ditch, or each ditch is double-row, and the adult is placed. The glyphs make the heads on both sides of the ditch line, each separated by a distance of 3 cm, and the matured dung soil is applied and soiled, slightly suppressed, and watered after planting.
Third, topdressing and watering, drainage
When the seedling height is 30 cm, the bracket can be erected to make the vine grow upward, maintain good ventilation, and reduce pests and diseases. Due to the strong growth in summer, attention should be paid to the topdressing and topdressing. Fertilization can be applied or watered in combination with watering; in summer, drainage should be paid attention to. Otherwise, soil over-wetting is unfavorable to root growth, and it is easy to grow into fork roots, affecting roots. The yield; however, the dryness of the soil will also reduce the yield, so pay attention to timely watering and drainage in the growing season.
Fourth, pests and diseases The main pests and diseases of yam are anthracnose, brown spot, etc., generally in the rainy season, serious damage, should pay attention to prevention and treatment.
Anthrax: Harm the stems and leaves. The affected stems and leaves produce brown spots that are slightly sunken, with irregular wheel patterns and small black spots.
Control methods: (1) After harvesting, the residual diseased leaves are burned intensively; (2) immersed in 1:1:150 Bordeaux mixture for 10 minutes before transplanting; (3) Spraying 65% of sensitized zinc 500 times solution during the onset period or 50% antibacterial 800-1000 times liquid, once every 7 days, 2-3 times in a row.
Brown spot: harms the leaves. Leaf spot lesions are irregular, brown, scattered small black spots, and sometimes perforated. Rainy and mantle are serious.
Control methods: (1) Regular rotation, and clean the pastoral, clearing the source of overwintering bacteria; (2) spraying 65% of sensitized zinc 500 times liquid or 50% dinitrogen absorbing 200 times liquid at the beginning of the disease, once every 7 days, continuous 2 - 3 times.
5. Harvesting and processing After the end of October, when the shoots in the upper part of the ground are yellow, the pearl buds are harvested first, then the scaffolds are removed, the vine leaves are removed, and then excavation is carried out, taking care not to dig. When harvesting, remove the top of the head and plant it. The roots of the small part are washed and fresh, and the outer skin is shaved with a bamboo knife. It is smoked in the wolf for 12-24 hours, and the yam is softened and then taken out. Or dry until the outer skin is dry, then stop drying, stacking and sweating, and then repeatedly drying and sweating several times until it is completely dry, that is, hairy yam.
Choose coarse and straight hairy yam, soak it in clear water and put it on the plate. Press it on the yam with a wooden board to make it into a cylindrical shape. Then cut both ends, and moisten it with sulfur. When dried, it is a light yam. Choose large and then use sulfur to smoke for 12-24 hours, dry or dries, then pack in wooden box or sputum, store in a ventilated and dry place, to prevent rats from eating and damp and mildew.
Sixth, quality identification
Mao yam is slightly cylindrical, slightly curved and slightly flat, generally 10-25 cm long, 1-3 cm in diameter 澌8, white surface, some with longitudinal groove wrinkles, some slightly flat, not rooted with cork There are light brown patches or small spots at both ends, the ends are not flush; the material is solid, the section is white, rich in powder, granular, no lignocellulosic structure, sweet and slightly acidic.
The light yam is cylindrical, generally 10-20 cm long and 1-3 cm in diameter. The surface is white and smooth, the ends are flat, and the other is the same as Mao Yam.
Both kinds of yam are well-dried, solid, powdery, and white. The quality is loose, the powder is small, and the color is yellow and white. If you do not go to the skin, the quality is loose, and the color brown is not suitable for medicine.