What kind of environmental conditions does Codonopsis pilosula cultivation require?

Codonopsis pilosula is also known as three-leaf vegetable, single leaf, and stinking codonopsis. It is a perennial climbing herbaceous plant of the Campanulaceae family. Codonopsis pilosula is a commonly used traditional Chinese medicine, originally from Shangdang, Shanxi; its root resembles ginseng, hence the name codonopsis. The root is used medicinally and has the functions of tonifying qi and nourishing blood, harmonizing the spleen and stomach, promoting fluid production and clearing the lungs. There are many varieties of codonopsis medicinal material, such as Western codonopsis, mainly produced in Gansu, Shanxi, Sichuan and other provinces; Eastern codonopsis, mainly produced in the northeastern provinces; Lu codonopsis, mainly produced in Shanxi, Henan and other provinces. The Tai codonopsis among the Western codonopsis is especially the best in quality. Codonopsis is a deep-rooted plant that prefers a cool and moist climate. It likes to grow on deep, loose-textured, fertile fill soil; waterlogged, low-lying, saline-alkali land and black clayey soil are not suitable for planting, and continuous cropping is taboo.

Cultivation techniques:

Codonopsis pilosula is propagated by seeds, and freshly harvested seeds must be used, because seeds from the previous year have a very low germination rate or lose their germination capacity. Seedling raising followed by transplanting is often used. The seedling plot should be chosen on a semi-shaded, semi-sunny slope, with loose and fertile sandy loam soil, close to a water source; apply about 1500 kg of manure or compost per mu, then plow, harrow fine, and level to make flat beds or raised beds. The sowing period can be from after the soil thaws in early spring to before the soil freezes in early winter; it is generally sown in the rainy season of July and August or before freezing in autumn and winter, which gives a high emergence rate and strong seedlings. Spring sowing often suffers from spring drought, making emergence difficult or uneven; where irrigation conditions exist, spring sowing may be used. To make the seeds germinate earlier, warm-water soaking treatment may be used. That is, use warm water at 40-50°C, add the seeds while stirring, and when the water temperature is about the same as hand temperature, let them sit for another 5 minutes; then place the seeds in gauze, wash them several times with clean water, and place them on a sand pile indoors at 15-20°C, rinsing once with clean water every 3-4 hours; after 5-6 days the seeds will crack open and can be sown.

Broadcast sowing or drill sowing is used.

For broadcast sowing, scatter the seeds evenly over the bed surface, cover with a little thin soil, just enough to cover the seeds, then press lightly so the seeds are firmly combined with the soil to favor emergence; the sowing rate is about 1 kg per mu;

For drill sowing, open furrows 1 cm deep at a row spacing of 10 cm, scatter the seeds evenly in the furrows, and likewise cover with thin soil; the sowing rate is 0.5-1 kg per mu. After sowing, cover the bed surface with corn stalks, millet straw, or pine and fir branches to retain moisture; afterward, water appropriately and keep the soil moist regularly to favor emergence. When the seedlings are about 5 cm tall, gradually remove the covering grass, but do not remove it all at once, to prevent the seedlings from being scorched to death by the hot sun. When the seedlings are about [X] cm tall, they have gradually been hardened and their adaptability to light has increased, so all the covering can be removed. They can also be intercropped with corn, @#@245@#@ and other crops. Corn should not be planted too densely; if too dense, the lower leaves of the corn should be removed. When the seedlings are about 10 cm tall, excess dense and weak seedlings can be thinned to maintain a plant spacing of 1-3 cm. The seedlings grow slowly, so timely loosening of the soil and weeding should be noted, to avoid large weeds with deep roots harming the codonopsis seedlings when pulled, or pulling out nearby seedlings as well. The seedling plot generally does not need fertilizer, and moisture should be properly controlled; during the seedling stage, water little but often, and after the seedlings grow larger, reduce the number of waterings; pay attention to drainage during the rainy season.

Codonopsis seedlings can be transplanted after growing for one year. The field production site should be chosen as loose, fertile sandy loam with a sunny aspect. When preparing the land, apply 3000 kg of barnyard manure or compost per mu, or add 30-50 kg of superphosphate, then deep plow 25-30 cm, harrow fine and level, and make beds about 120 cm wide; hillside fields generally do not need beds, and can simply be leveled along the slope direction. After the land is prepared, transplant from mid-October to before freezing in November in autumn, or after the soil thaws in early spring and before the seedlings sprout. Open furrows 15-20 cm deep at a row spacing of 20-30 cm; on hillside fields, open furrows horizontally along the slope, place the root stocks obliquely in the furrows at a plant spacing of 6-10 cm, then cover with about 5 cm of soil; about 25 kg of seed roots are used per mu. After planting, follow general management; codonopsis is a herbaceous vine, so trellises should be set up to let the stems and vines climb and grow. Set up the trellis when the seedlings are 30 cm tall; generally bamboo poles can be used to build an inverted-V-shaped trellis, with the aim of improving ventilation and light penetration, increasing the photosynthetic area, promoting growth, and according to reports, increasing disease resistance and raising codonopsis yield.

Harvesting and processing:

Codonopsis is generally harvested in autumn two years after transplanting, though some are harvested after 3 or 4 years. For the dug-out codonopsis, cut off the vines, shake off the soil, spread it on the drying yard, and sun-dry until it is 30-40 percent dry and soft; then according to thickness and size, grasp it into bundles by hand, place on a wooden board, rub with the hands and then sun-dry again, repeating this 3-4 times until dry. In the rainy south, a charcoal fire bed may be used; control the temperature in the bed at about 60°C, turn frequently, and when the roots are soft, take them out and rub, then dry again, similarly repeating several times until fully dried. The purpose of rubbing is to make the roots straight, dry evenly, and have tight skin and flesh with a soft, moist texture. Generally 2 kg of fresh codonopsis can be processed into 1 kg of dried goods; the yield of dried goods is 250-400 kg per mu, and high-yielding plots can reach 500 kg.

Disease control:

1. Rust disease

On infected leaves, the underside is slightly raised (summer spore pustules), and later ruptures to release orange-yellow powder (summer spores); in severe cases the leaves die, affecting growth; the disease is generally more serious in autumn.

Control method: after harvest, remove dead plants and diseased leaves and burn them in a centralized manner; at the early stage of disease, spray 50% dinitro dispersible 200-fold solution or 25% triadimefon 1000-fold solution, once every 7-10 days, for 2-3 consecutive sprays.

2. Downy mildew

Irregular brown lesions appear on the leaf surface, and gray mold-like matter appears on the underside of the leaves (conidiophores and conidia), often causing the plant to die.

Control method: remove diseased plants and withered residual leaves and burn them in a centralized manner; during the disease period, spray 40% shuangyiling 300-fold solution or 70% chlorothalonil 1000-fold solution, once every 7-10 days, for 2-3 consecutive times.