What are the key cultivation techniques for figwort (Xuanshen)?
Figwort, also known as Yuanshen, Heishen, or Zhejiang figwort. It is a perennial herb, with its roots used as medicine. It has the effects of nourishing yin and reducing fire, moistening dryness and promoting fluid production, reducing swelling and detoxifying. Its nature is slightly cold, and its taste is sweet, bitter, and salty. It is used to treat conditions such as yin deficiency with excessive fire, restlessness and insomnia, tidal fever, night sweats, sore and swollen throat, red eyes, lymphatic tuberculosis, carbuncles and sores, and constipation due to fluid deficiency. It is mainly produced in Zhejiang, Chongqing, and other areas along the Yangtze River basin.
Morphological Characteristics
Perennial herb. Roots long cylindrical or spindle-shaped. Stems four-angled, with grooves. Lower leaves opposite, upper leaves sometimes alternate, ovate to lanceolate, 10-15 cm long, margins finely serrate, teeth revolute, bony, with protruding tips. Cymes paniculate, large and loose, axis with glandular hairs; calyx 5-lobed, lobe margins membranous; corolla brown-purple, upper lip longer than lower lip; staminodes nearly round. Capsule ovate. Flowering period July-August, fruiting period August-September.
I. Growth Habits
Figwort has wide adaptability, prefers a warm and humid climate, and has a certain tolerance to cold and drought. Loam soil with deep, fertile, loose, and well-drained soil is preferable. It is not suitable for continuous cropping.
II. Site Selection and Land Preparation
Figwort is not suitable for continuous cropping. A field with a previous crop of grasses or legumes, good drainage, deep soil, and humus-rich sandy loam can be selected for planting. A sunny, wind-sheltered, low-slope site is preferable. Heavy clay soil and sites prone to waterlogging are not suitable for planting. When deep plowing and leveling the land, remove residual plant debris and fallen leaves, pick out stones, and make the soil loose. Apply 1500-2500 kg of barnyard manure or compost per mu as base fertilizer. After fine raking and leveling, make beds about 1.3 m wide, 20-25 cm high, with 40 cm wide furrows. On hillside land, make beds across the slope to prevent soil erosion, and also pay attention to opening drainage ditches around the perimeter.
III. Planting
Figwort is generally propagated asexually by adventitious buds. It can also be propagated sexually or by division.
1. Daughter bud propagation
Seed bud selection and storage: When harvesting figwort in late autumn and early winter, select white adventitious buds that are disease-free, robust, have few lateral buds, and are 3-4 cm long, and twist them off from the rhizome head to keep as propagation material. Buds that are red-purple or bluish, or flowering buds (with cracked bud scales), thin buds, and diseased daughter buds should not be kept for seed use. After collection, spread the seed buds indoors for 1-2 days to avoid heating and rotting after being put into pits. Choose a high, dry, well-drained place to dig a storage pit 30-40 cm deep; the length and width should not be too large. Place the seed buds into the pit to a thickness of about 33 cm, pile them into a steamed bun shape, cover with 7-10 cm of soil, and later, depending on the drop in temperature, gradually add more soil or cover with rice straw to prevent the seed buds from freezing. Generally, about 100 kg of seed buds are placed in each pit. Drainage ditches should be opened around the pit. During the storage period of seed buds, check promptly and turn the pit in time if mildew, sprouting, or rooting is found. Before early spring, as the weather warms, gradually remove the covering soil to prevent the seed buds from elongating. Indoor cellar storage can also be used; during storage, keep the temperature below 5°C and be careful not to let it heat up and burn the pile, causing the seed buds to elongate or dry out. Planting time and method: Generally, planting from December to March of the following year is better the earlier it is done. In Zhejiang, planting is generally done from late December to mid-January. On the prepared bed surface, open holes at a row spacing of 35×35 cm, place 1-2 seed buds in each hole with the bud tip facing upward, cover with a handful of burnt mud ash, and cover with soil about 5 cm thick. Use 40-80 kg of seed per mu. After planting, water to keep the soil moist.
In Nantong, Jiangsu, the seed buds are taken directly when harvesting figwort and planted immediately.
2. Seed propagation
This can be used in newly introduced planting areas. In the north, use a cold frame for seedling raising in early spring in March. First water the prepared seedbed thoroughly, and after the water seeps down, evenly broadcast or drill the seeds, sift some fine soil to cover the seeds completely, cover the bed surface with a layer of rice straw to keep warm and moist, and remove the covering straw when seedlings emerge. Thin seedlings 2-3 times; if the seedlings are weak, apply a small amount of fertilizer. In early to mid-May, when the seedlings are 5-7 cm tall, they can be transplanted. The plant and row spacing and field management are the same as for asexual propagation. In the south, seed propagation mostly uses autumn sowing for seedling raising; plants grow faster, and yield and quality are also better than with spring sowing.
IV. Field Management
1. Topdressing: Generally, topdressing is applied 3 times during the growing period. Apply the first fertilizer after the seedlings are fully established, applying 500-1000 kg of human and animal manure per mu to promote seedling growth. When the seedlings are about 35 cm tall and figwort growth is about to enter the vigorous period, carry out the second topdressing, applying 1000-1500 kg of human and animal manure and 1500 kg of barnyard manure per mu to promote vigorous aboveground growth. At this time the temperature is relatively high, so a layer of leaves or tender grass should be spread between the rows to lower the soil temperature and maintain soil moisture. In early to mid-July, at the early flowering stage of figwort, carry out the third topdressing, mainly with phosphorus and potassium fertilizers, applying 50 kg of superphosphate and 300 kg of plant ash per mu in furrows, then covering with soil, to promote the expansion of figwort root tubers.
2. Intertillage and weeding: After the seedlings emerge, carry out timely intertillage and weeding. The first time is in mid-April, after the seedlings are fully established; the second time is in mid-May; the third time is in mid-June. Intertillage and weeding should not be too deep; the degree should be to loosen the surface soil without damaging the root tubers.
Hilling: Hilling is generally carried out after the third fertilization, banking soil from the bottom of the furrow beside the plants. This protects the growth of the rhizome area and increases the number of white seed buds.
3. Irrigation and drainage: Figwort is relatively drought-tolerant and generally does not need irrigation. If there is a long drought, water before the sun comes out. In the rainy season, open ditches for drainage to prevent waterlogging from causing root tuber rot.
4. Bud removal: From the formation of flower buds on the upper part of the topped plant to the early flowering stage, remove the flower stalks in time to reduce nutrient consumption, so as to promote the expansion of underground root tubers and improve yield and quality.
V. Pest and Disease Control:
1. Figwort leaf spot blight: Caused by a type of imperfect fungus. It occurs easily under high temperature and high humidity, is more severe from June to August, and can continue until October. When the disease is severe, the entire plant turns brown and dies. Control methods: After harvesting figwort, promptly remove residual plants and diseased leaves from the field and burn them in a centralized manner; choose grass crops for rotation, and try to avoid rotation with crops such as Atractylodes macrocephala, sweet potato, peanut, Rehmannia glutinosa, and white peony; apply organic fertilizer after it is thoroughly decomposed, and frequently carry out intertillage and weeding to promote robust plant growth and enhance disease resistance; pay attention to opening ditches for drainage, reduce field humidity, and increase ventilation and light penetration; promptly remove diseased leaves at the early stage of the disease. Spray 1:1:100 Bordeaux mixture every 7-10 days for protection, continuously 3-4 times. From mid-May, spray 500-800 times diluted amobam solution, once every 10-14 days, continuously 4-5 times.
2. Figwort leaf spot disease: This disease damages leaves, begins to occur in mid-April, is more severe before June, and gradually lessens after July. For control methods, refer to leaf spot blight.
3. Figwort southern blight: Mainly damages roots and rhizomes, and occurs more in the south. It begins to occur in mid-April, with the peak period from late June to early August during the hot and humid season, and can continue until September. Poor soil drainage and application of undecomposed organic fertilizer can both worsen the disease. The affected figwort roots rot, and diseased plants quickly wilt and die. Control methods: Rotate with grass crops, avoid continuous cropping, and do not rotate with susceptible crops such as Rehmannia glutinosa, aconite, white peony, Pseudostellaria heterophylla, and peanut; during land preparation, apply 1.5 kg of 30% phygon or 50 kg of lime per mu and turn it into the soil for soil disinfection; soak planting stock in 1000 times diluted 50% thiophanate-methyl (or 50% Tuzet) for 5 minutes, then dry before planting; strengthen field management, pay attention to ditch drainage and ventilation with light penetration, and use high beds for planting in rainy areas; when diseased plants are found, pull them out promptly, remove and burn them, remove the soil from the diseased holes, and scatter lime powder in and around the diseased holes for disinfection.