Cultivation techniques of Polygonatum odoratum

Polygonatum odoratum is a perennial herb of Liliaceae. The rhizome is transverse, fleshy yellow-white, dense and mostly fibrous roots. The leaves are green and gray below. Flowers axillary, usually 1-3-fascicled. It is native to southwest China, but it is widely distributed in the wild. Cold-resistant, shade-resistant, like wet environment, suitable for growing in loose soil rich in humus. The rhizome of Polygonatum odoratum can be used for medicinal purposes, and the traditional Chinese medicine is also known as Polygonatum odoratum. It is picked in autumn, washed, sunburned and softened, kneaded repeatedly, dried in the sun, or steamed through, kneaded to translucent, sun-dried, and cut into thick slices or sections.

Growth habit

The seed of Polygonatum odoratum belongs to the type of epicotyl dormancy. The post-embryonic ripening stage requires a temperature of about 25 ℃, and the epicotyl needs a low temperature stage to break dormancy. After the seeds were sown, they only grew roots in the first summer and did not grow seedlings until April of the following year.

The rhizome of Polygonatum odoratum survives for 3 or 4 years, after which it will rot. Polygonatum odoratum planted in autumn sprouts from March to April of the following year. During the period from germination to emergence, the growth is relatively slow and the stem is weak. From May to June, the temperature gradually rises, the stems and leaves grow rapidly, and can bud and blossom. In the high temperature season in July, the growth of aboveground part weakened, while the growth of rhizome accelerated. In the second year after planting, the plant grew weakly and had poor adaptability to the environment, so it could not stand the direct sunlight in the high temperature season. In the third year, the plant grew tall, the stem increased, the rhizome developed rapidly and the growth ability was strong. In the fourth year, the aboveground stems increased, grew rapidly, the canopy density increased, and the rhizomes crisscross in the ground.

Cultivation techniques

1. Land selection and preparation

Polygonatum odoratum is resistant to cold, shade and dampness, and avoid bright light and windy. Like the wet and cool climate, the planting land should choose sandy loam with leeward to the sun, good drainage, fertile and loose soil and deep soil layer. Do not cultivate in areas where the soil is heavy, barren, low-lying and prone to stagnant water. Avoid continuous cropping to prevent the occurrence of diseases and insect pests. The previous crop had better be legumes. After selecting the land, first apply organic fertilizer as base fertilizer, the amount of organic fertilizer per mu is 2500 kg-3000 kg, spread evenly on the ground, turn the soil 30 cm deep, fine rake to make a border, the width of the border is 1.0-1.30m, the width of the ditch is 25cm-30cm, and the depth is 15cm. Clean up the weeds and expose them to the hot sun.

2. Planting method

Polygonatum odoratum propagates with seeds and rhizomes, and the propagation rate is very fast. Propagation with rhizome, because its heredity is more stable than seeds, can ensure high yield, and the growth cycle is short, so this method is used in production at present. During harvest, the hypertrophic rhizomes with no insect pests, no black spots, no hemp spots, no damage, yellow and white color, full terminal buds, many fibrous roots, neat buds and slightly concave buds were selected from the stout plants. The branches that are thin and small and the bud tip is sharp and protruding outward and the old branches can not germinate and should not leave seeds; otherwise, the nutrition is insufficient, the vitality is not strong, affect the offspring, the quality is poor, the yield is low. It is not suitable to keep seeds with the main stem; because the main stem is large and long, the cost is too high, at the same time, the removal of the main stem will seriously affect the quality and is not easy to sell. To dig, choose, and plant as you wish. When you can't plant in time in case of weather changes, you must put the roots and buds in the leeward and cool place indoors. Generally every 667 square meters with 200,300 kilograms of seed stem. Soak the selected seed stem in a bucket containing more than 50% carbendazim 500 times the solution, soak the seed stem for 30 minutes, remove it and dry it. It is usually planted from July to November. Hole planting or strip planting. Hole planting: the border is planted in 3-4 rows, the row spacing is 30-40 cm, the plant spacing is 30-40 cm, and the hole depth is 8-10 cm. Each hole crosses, planting 3-4, the bud head crosses around, not in the same direction. Strip planting: open a ditch with a depth of 6 cm to 15 cm on the border surface according to the row spacing of 15 cm-30 cm. When planting, cut the rhizome of Polygonatum odoratum to grow about 3 cm-7 cm, arrange longitudinally according to the plant distance of 7 cm-17 cm at the bottom of the ditch, put the bud head in the same direction, and cover pig manure or soil fertilizer. The amount of rhizome is 250 kg-300 kg per mu.

3. Field management

The seedlings did not emerge in the same year after planting, and the weeds in the field should be cleared in time after emergence in the next spring. Pull out the soil by hand when it is dry, do not use a hoe, so as not to damage the rhizome and cause rot. It is not suitable to pull grass after rain or when the soil is too wet. After that, the weeds were cut once in May and July respectively. In the third year, weeds should only be pulled out by hand. Apply sufficient base fertilizer, combined with land preparation every 667 square meters into 2000-3000 kg of rotten farm manure. After planting and covering soil, 200 kg of coke mud ash or 30kg of compound fertilizer was applied to each mu of the cave. Fertilization is carried out before sprouting in spring to promote stem and leaf growth. When the seedling height is 7 to 10 centimeters, 667 square meters should be irrigated with 800 to 1000 kilograms of rarefied human feces or 10 kilograms of urea. Fertilization was carried out when Polygonatum odoratum entered dormancy, rotten pig manure and phosphate fertilizer were applied, and the soil was 5 cm-7 cm thick after application. After growing for 2 years, the rhizome of Polygonatum odoratum has many branches and crisscross, which is easy to be exposed to the surface and turn green, which affects the appearance and quality of goods and is vulnerable to freezing damage, so it is more necessary to cover the soil in time. Polygonatum odoratum most avoid stagnant water, before the arrival of rainy season, to dredge ditches to facilitate drainage. Soil cultivation is combined with fertilization every winter, and the soil is collected from the furrow to cultivate 3.0cm to 4.5cm. Polygonatum odoratum should be covered with straw, leaves or thatch. Every year in early winter, the stems and leaves of Polygonatum odoratum should be covered with grass and covered with a layer of soil.

Pest control

1. Disease

① leaf spot

Brown round disease spots grow on the leaf surface, and the edges are purplish red, which often occur in summer and autumn.

[prevention and treatment methods] before or at the initial stage of the disease, spray 1 rig 120 Bordeaux solution or 50% desenamine 800 times, once every 10 days, 2-3 times in a row.

② rust

There are yellow round disease spots on the leaf surface and yellow annular grains on the back.

[prevention and treatment methods] the diseased plants were pulled out and burned in time, and the acupoints were disinfected with quicklime.

③ root rot disease

When the disease occurs, the rhizome decays, which eventually leads to plant death.

[prevention and control methods] do a good job of drainage, reduce soil moisture and control the spread of diseases.

2. Insect pests

Mainly brown beetles, black beetles, red feet and green beetles, mainly harmful to the roots. Control method: apply fully mature organic fertilizer as base fertilizer or topdressing fertilizer; make poison bait with rice or wheat bran and spread it on the border in the evening; when the pest is serious, pour the root with 1000 times liquid of trichlorfon.

Harvesting and processing

1. Harvest

It is generally harvested in the third year after planting. It is harvested in autumn in the south and in spring in the north to link up with the planting time. After the aboveground part withered, it was harvested on sunny days and when the soil was relatively dry before sprouting in spring. When digging, first cut off the stem on the ground, dig up the rhizome, shake off the soil to prevent it from breaking. The rhizomes reserved for seed are stacked separately.

2. Processing

The dug-out rhizomes were graded according to length, short, thickness and fineness, and dried respectively. At night, add mulch after the Polygonatum odoratum is cool. Do not bag the uncooled Polygonatum odoratum so as not to heat up and deteriorate. Generally, after 2-3 days, the rhizome of Polygonatum odoratum will be very soft and not easy to break. Then remove the fibrous root and sediment, and then rub the rhizome on the slate or wood. When rubbing, it should be slow first and then fast, from light to heavy, until the rough skin is clean, the rhizome of Polygonatum odoratum has no hard heart, showing golden translucent shape, press by hand when there is syrup oozing, and then dry. In the northeast region, the wild Polygonatum odoratum was kneaded first and then dried, repeated 3-4 times until it was dried. Some people also adopt the processing method of combining steaming and kneading, that is, the fresh Polygonatum odoratum is softened and then steamed for 10 minutes, then the sugar juice is oozed with high temperature, and then packed in an airtight plastic bag. After about 30 minutes, rub with hands or the whole bag trample with feet, until Yuzhu is yellow and translucent, and then take out the sun. When processing, it is necessary to prevent excessive kneading, otherwise the color will become darker or even darker, affecting the quality of the goods.