Codonopsis Cultivation Techniques and Field Management Methods
The Chinese medicinal herb Codonopsis (Codonopsis pilosula) uses its root as medicine and grows at forest edges or in thickets. It is distributed in western Sichuan, Gansu, Shanxi, Henan, Inner Mongolia, Hebei, Shaanxi, Northeast China and other places. It is cultivated in most provinces and cities across the country. Its taste is sweet, and its nature is neutral. How is Codonopsis cultivated and managed in the field?
Morphological characteristics of Codonopsis
Perennial herbaceous vine. The cut surface of the whole plant has white milky juice and a peculiar odor. The root is long and cylindrical, sparsely branched, fleshy, with a surface ranging from grayish yellow to brown; the upper part has fine dense ring lines, while the lower part sparsely bears transverse elongated lenticels. The root head is swollen and bears numerous wart-like stem scars, commonly called “lion's mane head”. The stem is slender and much branched, with fine white hairs on the young parts. Leaves are alternate, opposite or pseudo-whorled; the leaf blade is ovate or broadly ovate, with a nearly heart-shaped base, hairy on both sides, entire or slightly wavy. Flowers are solitary, axillary; the calyx is 5-lobed, green; the corolla is bell-shaped, 5-lobed, yellow-green with purple spots. The capsule is conical; seeds are numerous, small, elliptical, brown, and glossy. The flowering period is August to October, and the fruiting period is September to October.
Cultivation
1. Land selection and preparation. For the seedling-raising land, a semi-shaded slope is preferable, with loose and fertile soil, rich in humus, and well-drained sandy loam. Apply 2000--3000 kg of barnyard manure per mu, 20--30 kg of diammonium phosphate, and 30--50 kg of superphosphate, then plow, harrow finely, and level to make flat beds. The width is 3---5 m, and the length depends on the terrain. The transplanting and permanent planting land should face shade. When planting on hillside land, beds are mostly not made; simply level along the slope.
2. Propagation methods. Seed propagation is used, often by raising seedlings and then transplanting, and direct sowing is seldom used.
(1) Seedling raising. Select current-year seeds and sow around White Dew; the germination rate can reach 85%. Current-year seeds can also be sown in the two seasons of spring and summer of the following year, but the germination rate is lower. Seeds stored for more than one year have a germination rate of less than 10% and cannot be used. Choose fertile, shaded plots for the seedling land, deeply plow, level, and harrow finely, then water thoroughly. Evenly scatter the seeds on top, give one pass with a 3--5 cm nail rake for fine raking, and cover with wheat straw for shade. The seedbed should be sprayed with water frequently to keep the soil moist. Use 2--3 kg of seeds per mu. Codonopsis seedling fields are not topdressed, to prevent excessive vegetative growth. After the seedlings emerge completely, remove the covering material; when the seedlings are about 6 cm tall, thin them appropriately to prevent overcrowding from affecting growth, and weed promptly.
(2) Transplanting. Lift the seedlings in late autumn or after the soil thaws in spring; do not injure or break the seedling roots, remove diseased and damaged plants, and tie them into small bundles. Autumn planting can increase the survival rate. On the prepared land, open furrows at a row spacing of 25--30 cm and a depth of about 15 cm, then place the Codonopsis seedlings along the furrow at a plant spacing of 10 cm, and cover with 5 cm of soil. Use 40--50 kg of seedlings per mu.
3. Field management
(1) Intertillage, weeding and topdressing. For Codonopsis after seedling raising or transplanting, carry out the first weeding when the seedlings are 6--10 cm tall, and when the seedlings are 15--18 cm tall, carry out the second weeding together with topdressing. During the growing period, Codonopsis should not receive excessive water; when drought is severe, water moderately, and apply urea or phosphate fertilizer at 10--15 kg/mu for topdressing.
(2) Trellising and seed collection. When Codonopsis seedlings are 30 cm tall, insert bamboo poles or branches between the rows so that the stems and vines can twine around them. Where the stems and vines are too dense, thin the branches appropriately to improve ventilation and light penetration. When the fruit turns from green to yellow-white and the seeds inside turn yellow-brown, cut down the stems and vines and dry them in the sun, shake out the seeds, remove impurities, store them in cloth bags, and place them in a dry, ventilated place for later use. If seeds are not being collected, trellising is not necessary; when the stems and vines exceed 30 cm, cut them off at any time to favor root growth.
4. Pest and disease control
(1) Rust disease. It occurs easily in rainy and humid seasons. Control method: after Codonopsis seedlings wither, clean the garden promptly and burn the diseased, withered, and residual leaves. In the early stage of the disease, spray 500--600 times diluted zineb solution; or 600--800 times diluted triadimefon solution.
(2) Root rot. It occurs easily in low-temperature and rainy seasons. Control: pay attention to drainage. In the early stage of the disease, drench the root area with 500 times diluted 50% carbendazim wettable powder.
(3) Underground pests. Mainly including white grubs, cutworms, wireworms, etc., which damage the roots. Poison bait can be used for trapping and killing with 3911, phoxim, and the like. The method is: use 0.50 kg of 3911 or phoxim per mu, mix with 5 kg of water, mix into 10--20 kg of oil residue, spread it before plowing, and plow as it is spread to prevent reducing the pesticide effect.