Latest Technical Guide for High-Yield Cultivation and Management of Coptis chinensis

Coptis chinensis, also known as Wanglian, Xuanlian, Chuanlian, Jizhualian, etc., is a plant of the Ranunculaceae family. The main cultivated species are Coptis chinensis (Weilian) and Coptis deltoidea (Yalian), with the rhizome used as medicine. It has the effects of clearing heat and drying dampness, purging fire and detoxifying, cooling blood and improving vision, eliminating damp-heat and stopping diarrhea and dysentery, and treating heart fire and liver heat, dizziness, red eyes, irritability, and heat toxin. It is mainly produced in Sichuan, Hubei, Shaanxi, Yunnan, Hunan, Guizhou, Fujian, Jiangxi, Anhui, Guangxi and other provinces and regions, where it grows wild or is cultivated in small quantities.

Plant Characteristics

Perennial herb. The underground rhizome is mostly branched, with a rough, yellowish-brown surface and many fine, slender fibrous roots. Leaves are clustered, with long petioles; leaflets number 3 to 5, with margins deeply cleft into pinnate lobes and serrated, light green and glossy. Flower stems emerge in late spring, reaching 100 cm in height, with terminal paniculate cymose inflorescences; flowers are small and yellow-green. The follicle fruits split open when mature; seeds are small and yellowish-brown. Coptis chinensis prefers cool, moist conditions and avoids high temperatures and dryness.

Growth Characteristics

Coptis chinensis prefers to grow in high mountain shady, moist and cool conditions, with a light transmittance of 30% to 40%, and avoids strong light, high temperatures, dryness, and waterlogged areas. It requires deep, fertile soil with good drainage and soil moisture of about 50% to 60%. The seeds have a post-embryonic after-ripening stage and can only germinate after low-temperature treatment; especially at the seedling stage, light tolerance is poor, and the larger the seedling, the stronger its light resistance becomes.

Cultivation Techniques

1. Land preparation and shading

In the past, frame shading was always used, which caused too much damage to forests. Now, understory planting, intercropping with corn, or simple sheds are used, keeping light transmittance at about 40%, with good drainage and soil moisture of about 50% to 60%. It fears waterlogging and direct light, so semi-shady, semi-sunny slopes of 15 to 25 degrees are best.

Land preparation: First clear residual debris, stones and other impurities from the ground surface outside the shed, pile them up, and burn them into black soil. Then dig and turn twice, break the soil fine and rake it level. Then, following the slope direction, make raised beds (boxes) 130 to 150 cm wide and 10 cm high, with ditches 16 to 26 cm wide, and make the bed surface tile-backed in shape, and dig drainage ditches around the shed. After the beds are prepared, apply 60,000 to 75,000 kg of decomposed cow and horse manure per hectare; crush it and spread it evenly on the bed surface, then shallow-dig to mix it evenly with the topsoil, and then cover with about 6 cm of burned soil.

Shading: Frame sheds and simple sheds are mostly used. For frame sheds, cut bamboo clumps and trees are used as shading material; length is 216 cm, post spacing is 200 to 230 cm, row spacing is 160 cm, posts are buried 30 to 50 cm deep, and all posts are 160 cm high. Then purlins and crossbars are placed on top, and shading material is covered over them. The shade density should be uniform, about 60% to 70%.

Simple shed: Use wooden forks 3 to 5 cm thick as supports; the shed height is 80 to 100 cm. Build as you plant; after planting one bed, build one shed.

2. Propagation methods

Two methods are used: seed seedling propagation and cutting propagation.

(1) Seed propagation method

Seed collection: Around the beginning of summer, collect seeds from healthy plants that have been transplanted for more than 3 years. When the seeds turn yellow-green, they should be harvested. On sunny days, pick the fruiting branches and pile them indoors for 1 to 2 days, then thresh. Avoid sun exposure, keep them moist, and treat them at low temperature to complete seed embryo after-ripening. In production, a hotbed is used, or humus is mixed evenly and buried in a pit 3 cm thick, then covered with 3 to 6 cm of sand or humus soil, and then covered with branches to retain moisture; check frequently.

① Fine seedling raising: Choose a semi-shady, semi-sunny, moist and fertile mixed forest or secondary wasteland, cut away weeds and unnecessary branches and burn them into charcoal as fertilizer, build a shade shed about 80 cm high and fence the edges, and deep-plow the land about 23 cm. Make raised beds 130 cm wide, with bed ditches 30 cm wide. The bed surface should be level, arched in shape, free of crushed stone and tree roots, and the soil fine. Apply 15,000 to 22,500 kg of decomposed cow and horse manure per hectare, and cover the bed surface with 1.5 cm of burned soil. Around November, take the stored seeds, mix them well with 20 to 30 times their volume of humus soil, and evenly sprinkle them on the bed surface (about 37.5 kg of seed per hectare), then sprinkle cow dung powder or plant ash 0.6 cm thick. In the spring of the second year, when the seedlings have grown 3 leaves, combine weeding with topdressing of clear manure water or urea. Chemical fertilizer should be applied in multiple small doses; apply ammonium sulfate at 75 to 112.5 kg per hectare, preferably on sunny days when there is no dew on the leaves, broadcasting it and then gently sweeping with a small bamboo branch to make the fertilizer fall off and prevent burning the seedlings. In June, apply humus soil to earth up and protect the seedlings. In November, apply 11,250 kg per hectare of fine cow manure or horse manure mixed with plant ash to help the seedlings overwinter.

② Forest seedling raising: Choose woodland with a shade density above 80% and tree height below 300 cm. After the land is prepared, sow about 75 kg of seed per hectare. The sowing method is basically the same as fine seedling raising. From mid-to-late February, before seedling emergence, clean fallen leaves once. After emergence and before transplanting, carry out 2 to 3 rounds of weeding and fertilizing. This method saves labor.

Transplanting: Transplant in the spring of the second year after emergence, at a row spacing and plant spacing of 10 cm * 10 cm and a depth of 3-5 cm. In addition, Coptis chinensis can also be planted in forests, using about 70% shading as a natural canopy, with the same method as above. It can also be intercropped with early-maturing tall-stem crops such as corn. First sow corn, open holes at a plant spacing of 30 cm, and insert them on both sides of the bed, with 3-4 seeds per hole; when thinning, keep one seedling. In July, when the corn canopy closes, plant Coptis chinensis seedlings in the bed between the corn rows at a row spacing and plant spacing of 10 cm * 10 cm. After the corn is harvested, build 100 cm high frames on both sides of the bed and place the corn stalks evenly on the frames for shade. Re-sow corn every year; in the second year the plant spacing is 40 cm, in the third year 50 cm, in the fourth year 60 cm, and in the fifth year 60 to 100 cm.

(2) Cutting propagation

This method can be used in areas lacking seeds or seedlings. That is, after Coptis chinensis has been cultivated for 5 years, harvest early in August to September. After harvesting, remove the Coptis chinensis plant together with stems and leaves from 0.1 to 0.13 cm below the top of the rhizome (cut off) for use as cuttings, planting immediately after cutting. When planting, the petiole should be buried entirely in the soil, leaving only the leaf blade outside, and then pressed firm. The land preparation, bed making, and fertilizing for this method are the same as above, and it also takes 5 years to harvest.

Field Management

The key to achieving high yield and high quality in Coptis chinensis lies in field management. Attention should be paid to topdressing and weeding. Within 3 to 5 days after planting, fill any gaps immediately, and apply fertilizer, clear manure water or pig manure water to help the seedlings grow. One month after rooting, apply 7.5 to 10 kg of ammonium sulfate. In October to November, apply 30,000 to 37,500 kg of decomposed cow and horse manure per hectare. In the early stage, nitrogen fertilizer is the main type; in the later stage, spread a thin layer of burned soil. Thereafter, fertilize and earth up once each in spring and autumn every year. In spring, apply 112.5 to 150 kg of ammonium sulfate per hectare or 15,000 to 22,500 kg of human excrement or humus per hectare. For winter fertilizer, apply 37,500 to 60,000 kg per hectare of decomposed cow and horse manure, or cake fertilizer, superphosphate, lime, etc. After applying winter fertilizer, burned soil must be earthed up. After 3 to 4 years, apply less or no nitrogen fertilizer, focusing mainly on phosphorus and potassium fertilizers. Note that no topdressing should be applied before harvest. For Coptis chinensis, weeding from small seedlings to harvest is very important; remove weeds as soon as they appear. In the seedling stage, pull them out by hand to achieve complete weeding, removing them while small and thoroughly. While weeding, pay attention to earthing up, first thin and then thicker year by year: 1.5 cm thick in the second year, and 1.5 to 3 cm thick in the third and fourth years. During management, attention should be paid to adjusting the shade density. Within 3 years, shading should be checked frequently; where shade is missing, cover it quickly. Shading decreases year by year. If frame sheds are used, in the harvest year after the seeds are collected, remove the shading material and let Coptis chinensis grow in sunlight, so that nutrients are transferred to the rhizome and the roots become firm. If Coptis chinensis is used as cutting propagation material, the shed can only be pulled down at harvest. If Coptis chinensis is planted in forests, begin pruning branches in the third year after planting, with 50% shade, 30% in the fourth year, and 20% in the fifth year.

Disease and Pest Control

(1) Powdery mildew

It mostly occurs on new leaves of the current year, forming snow-white powder, then becoming water-soaked, and the leaves gradually turn red and dark brown. At this time, pig manure water can be applied as topdressing to make the seedlings turn green again, and then 0.3 to 0.5 degrees Baume lime-sulfur mixture can be sprayed for control.

(2) Rodent damage and animal damage

Coptis chinensis has many animal enemies, such as deer, golden pheasants, and rodents. They damage the young leaves, flower stems, and seeds of Coptis chinensis, and some also damage the rhizome. This generally occurs in the cold season from December to April of the following year. To prevent rodents, zinc phosphide and corn flour can be mixed at 1:20 into poison bait and scattered in the field or in rodent holes.

Harvesting and Processing

Harvest in October to November of the fifth year after planting. Dig out the whole Coptis chinensis plant, shake off the mud and sand, then cut off the fibrous roots and the aboveground parts together. Dry the fibrous roots and leaves separately for veterinary use. Dry the rhizome separately. When drying over a heated bed, the heat should be even; at the beginning, the heat should not be too strong and should be increased gradually. Generally, when the rhizome breaks easily and the cross-section is licorice-colored, it can be removed from the bed. While hot, put it into a trough cage and push and rub it to remove remaining mud, sand, fibrous roots, and petioles, yielding the finished product.