Detailed Explanation of Cultivation and Processing Techniques for the Chinese Medicinal Herb Coptis chinensis
Coptis chinensis is a perennial evergreen herbaceous plant of the Ranunculaceae family. Its rhizome is used as medicine; it is cold in nature and bitter in taste, and has the effects of purging fire, drying dampness, and detoxifying. It is mainly produced in Hubei, Sichuan, Yunnan, Shaanxi, Hunan, Zhejiang and other provinces in China. It is mainly used to treat indigestion, stop diarrhea and relieve pain, and has anti-inflammatory effects. Due to differences in production areas and species, commercial Coptis chinensis can be divided into Weilian, Yalian, and Yunlian. Among them, Weilian has the largest planting area, mainly distributed in eastern Sichuan, western Hubei, and southern Shaanxi; Yalian is mainly produced in Hongya County and Ya'an City in Sichuan; Yunlian is mainly distributed in northwestern Yunnan.
Coptis chinensis generally grows in high-cold mountainous areas at an altitude of 1200-1800 m, and prefers a shady, humid, and cool climate. In winter, it can overwinter normally within minus 8 °C. It has relatively high water requirements and is not tolerant of drought. Because its rhizome is shallow and its leaf area is large, it needs more water, but it cannot tolerate waterlogging; therefore, drainage must be carried out in time during the rainy season. Coptis chinensis is a shade-loving plant and avoids strong direct light. It prefers weak light, and seedlings are most afraid of strong light. Therefore, shade frames must be built for cultivating Coptis chinensis, with about 50% light transmission.
Cultivation Techniques for Coptis chinensis
1. Land selection and preparation. Choose fertile soil with deep humus and good drainage, sandy loam, with a slope within 20°. Dig out the weeds on the ground, plow, turn, and rake level, and make raised beds 1.3 m wide.
2. Propagation methods. Coptis chinensis is propagated by seeds and cuttings, but seed propagation is mostly used in production. In early May, the seeds are harvested immediately after they mature. The embryos of the harvested seeds have not yet differentiated, so the seeds must be treated before sowing. The seeds are treated by sand storage. By November, the sand-stored seeds begin to crack and can then be sown.
3. Building shade frames. Coptis chinensis seedlings are afraid of sunlight, so shade frames must be built for shade. The shade frame is 70-80 cm high, and covering it with pine branches is sufficient.
4. Sowing and seedling raising. In October-November, after the sand-stored seeds have cracked, they can be sown. The sowing rate is about 1.5-2.5 kg per mu, covered with 1 cm of dry fine soil, and then a layer of decomposed cow or horse manure is sufficient.
5. Seedling field management. Coptis chinensis seedlings grow slowly, so weeds must be removed in time, and quick-acting nitrogen fertilizer should be applied as a top dressing. By late May, Coptis chinensis seedlings can produce three true leaves. In the third year after sowing, they can be lifted from the nursery for transplanting. Generally, 1 kg of seeds can raise 100,000-200,000 Coptis chinensis seedlings.
6. Transplanting. Vigorous seedlings with more than 4 true leaves and a plant spacing of more than 6 cm should be selected. Transplanting time is mostly in spring and autumn. Spring planting has a high survival rate and vigorous growth. Autumn planting is inferior to spring planting. At transplanting, the spacing is 10 cm × 10 cm, and about 60,000 seedlings are planted per mu, with a planting depth of 3-5 cm, leaving 3-4 large leaves above the ground. After transplanting, follow conventional field management and work management. Be sure to remove weeds in the field in time, apply top dressing in time, and at the same time earth up the soil, which is beneficial for increasing yield.
7. Pest and disease control. Coptis chinensis has relatively few diseases. Powdery mildew occurs more often in the rainy season and can be controlled by conventional methods. When cultivating Coptis chinensis in mountainous areas, wild animals and rats cause relatively great damage to Coptis chinensis fields, so guards should be assigned.
Harvesting and Processing of Coptis chinensis
Coptis chinensis can only be harvested in the 5th year after transplanting, making it a medicinal plant with a relatively long growth period. The most suitable harvesting period for Coptis chinensis is early October and late November before freezing. Use a four-tooth rake to dig out Coptis chinensis according to the row and plant spacing, cut off the fibrous roots and leaves, and about 500 kg of fresh roots can be produced per mu. After the fresh roots are dug out, it is best to dry them with a heated bed. When drying, the firepower should not be too strong; turn them while drying until they are dry. Generally, the yield is about 100 kg of finished dried Coptis chinensis rhizomes per mu.