Detailed Explanation of Key Techniques for High-Yield Cultivation of Codonopsis pilosula

Codonopsis pilosula gets its name from its place of origin, "Shangdang Commandery," and is a perennial herbaceous vine of the Campanulaceae family. Its root is used as medicine. It is distributed across various provinces in the Northeast, Northwest and other regions. At present, the largest area under artificial cultivation is Weiyuan County in our province, which enjoys the reputation of "China's Hometown of Codonopsis pilosula." Pharmacological experiments have shown that Codonopsis pilosula has a blood-sugar-raising effect, can increase red blood cells and hemoglobin levels, raise blood concentration and reduce white blood cells, and also has blood-pressure-lowering and coagulation-promoting effects. Its taste is sweet, and its nature is neutral. It has the functions of tonifying qi, enriching blood and promoting fluid production. It is used for spleen deficiency, poor appetite with loose stools, fatigue of the limbs, shortness of breath and coughing, weak speech, dizziness due to blood deficiency, palpitations, and dry mouth and thirst due to fluid depletion.

I. Plant Characteristics and Variety Introduction

1. Plant characteristics. The root is conical, fleshy, with an enlarged top bearing numerous stem scars, commonly known as a "lion's head." The twining, trailing stem is much branched and can reach about 2 m in height. The young tender parts bear fine white hairs. The leaves are alternate, opposite or falsely whorled; the leaf blade is ovate or broadly ovate with a nearly heart-shaped base. All parts have milky sap in cross-section and a distinctive foul odor. The flowers are light green and stalked. The capsule is conical, and the seeds are numerous, small, brown and glossy. The flowering period is August to September, and the fruiting period is September to October.

2. Variety introduction. At present there are many production areas for Codonopsis pilosula, and the varieties and names are complex. Based on regional proximity and quality, the products are divided into five types: Xidang, Dongdang, Ludang, Tiaodang and Baidang, among which Xidang and Dongdang are wild products, while the rest are cultivated varieties.

II. Biological Characteristics

1. Growth and development. Codonopsis pilosula prefers a cool climate, and high mountain regions at an altitude of 1800--3000 m are more suitable for its growth.

2. Requirements for environmental conditions. High temperatures are unfavorable to its growth. It has strict requirements for light: seedlings prefer shade, while mature plants prefer sunlight. Codonopsis pilosula is not suitable for continuous cropping, as continuous cropping readily leads to pests and diseases. Potato is the best preceding crop for Codonopsis pilosula.

III. Cultivation Techniques

1. Land selection and preparation. For the seedling nursery, a semi-shaded slope is preferable, with loose, fertile soil rich in humus and well-drained sandy loam. Apply 2000--3000 kg of barnyard manure, 20--30 kg of diammonium phosphate and 30--50 kg of superphosphate per mu, 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 site should face shade. When planting on hillside land, beds are mostly not made; simply level the land along the slope.

2. Propagation method. Seed propagation is used, commonly by raising seedlings and then transplanting, and direct sowing is rarely used.

(1) Raising seedlings. Select current-year seeds and sow them 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 until the year after next have a germination rate of less than 10% and cannot be used. Choose a fertile, shaded plot for the seedling nursery, deep-plow, level and harrow finely, and water thoroughly. Evenly scatter the seeds on top, give one pass with a 3--5 cm rake to scratch them in lightly, 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. Fertilizer is not applied to Codonopsis pilosula seedling fields 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 excessive density from affecting growth, and weed promptly.

(2) Transplanting. Lift the seedlings in late autumn or after the soil thaws in spring, taking care not to damage or break the seedling roots. Remove diseased and damaged plants and tie the seedlings into small bundles. Autumn planting can improve 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 seedlings in the furrows 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 pilosula after seedling raising or transplanting, carry out the first weeding when the seedlings are 6--10 cm tall, and carry out the second weeding together with topdressing when the seedlings are 15--18 cm tall. During the growing period, Codonopsis pilosula should not receive excessive water; water moderately when drought is severe. For topdressing, use urea or phosphate fertilizer at 10--15 kg/mu.

(2) Trellising and seed collection. When the Codonopsis pilosula seedlings are 30 cm tall, insert bamboo poles or tree 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 facilitate ventilation and light penetration. When the fruits turn from green to yellow-white and the seeds inside become yellow-brown, cut down the stems and vines and sun-dry them, shake out the seeds, remove impurities, and store them in cloth bags in a dry, airy 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 is prone to occur in rainy and humid seasons. Control method: after the Codonopsis pilosula seedlings wither, clean the field promptly and burn the diseased, withered and residual leaves. In the early stage of the disease, spray with zineb 500--600 times dilution, or triadimefon 600--800 times dilution.

(2) Root rot. It is prone to occur at low temperatures and in rainy seasons. Control: pay attention to drainage. In the early stage of the disease, drench the roots with 50% carbendazim wettable powder 500 times dilution.

(3) Underground pests. These mainly include 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, blend into 10--20 kg of oil residue, and scatter it before plowing, scattering and plowing as you go to prevent reducing the pesticide efficacy.

IV. Harvesting and Processing

Generally, 1 year after transplanting, dig out the roots, shake off the soil, sort them by thickness and size, and sun-dry them until soft; then grasp and bend them by hand and sun-dry again, repeating 3--4 times until dry. In Codonopsis pilosula production areas, there is also a method of grading the roots by size, threading them with nylon rope into strings 3--5 m long, and hanging them on racks set up in advance to sun-dry. The advantage of this method is that it saves drying space and facilitates ventilation and drying. Roots that are thick and large, with tight skin and flesh, a soft and moist texture, and a sweet taste are considered best. The dry-to-fresh ratio is about 2:1. The yield per mu is 300--400 kg.