How to grow Asarum sieboldii? Detailed field cultivation techniques
Asarum sieboldii, aliases: Asarum sieboldii, Asarum sieboldii, Latin name: Asarum sieboldii Miq. Aristolochiaceae, Asarum genus perennial herb; rhizome erect or creeping horizontally, diameter 2-3 mm, internode length 1-2 cm, with multiple fibrous roots. Leaves usually 2, leaf blade cordate or ovate-cordate, apex acuminate or acute, base deeply cordate, apex rounded, sparsely short-hairy on the upper surface, denser on the veins, hairy on the lower surface only on the veins; stamens inserted at the middle of the ovary, filaments nearly equal to or slightly longer than anthers, connective prominent, short conical; ovary semi-inferior or nearly superior, globose, relatively short, stigma lateral. Fruit nearly globose, diameter about 1.5 cm, brownish-yellow. Flowering period April-May.
Morphological characteristics of Asarum sieboldii
Perennial herb; rhizome erect or creeping horizontally, diameter 2~3 mm, internode length 1~2 cm, with multiple fibrous roots. Leaves usually 2, leaf blade cordate or ovate-cordate, length 4~11 cm, width 4.5~13.5 cm, apex acuminate or acute, base deeply cordate, lateral lobes 1.5~4 cm long, 2~5.5 cm wide, apex rounded, sparsely short-hairy on the upper surface, denser on the veins, hairy on the lower surface only on the veins; petiole 8~18 cm long, smooth and hairless; bud scale leaves reniform-orbicular, both length and width about 13 mm, margin sparsely pubescent. Flowers purple-black; pedicel 2~4 cm long; perianth tube campanulate, diameter 1~1.5 cm, inner wall with distant longitudinal ridge wrinkles; perianth lobes triangular-ovate, about 7 mm long, about 10 mm wide, erect or nearly spreading; stamens inserted at the middle of the ovary, filaments nearly equal to or slightly longer than anthers, connective prominent, short conical; ovary semi-inferior or nearly superior, globose, style relatively short, apex 2-lobed, stigma lateral. Fruit nearly globose, diameter about 1.5 cm, brownish-yellow. Flowering period April~May. Rhizome irregularly cylindrical, with short branches, 1-20 cm long, 1-4 mm in diameter; surface grayish-brown, with annular nodes, internodes 1-10 mm long; roots slender, densely borne on nodes, 5-20 cm long, about 1 mm in diameter. Surface grayish-yellow, with slender branch roots; roots brittle, easily broken, fracture smooth, yellowish-white or white. Odor aromatic and strong, taste pungent, numbing to the tongue.
Field cultivation techniques of Asarum sieboldii
1. Site selection and land preparation Asarum sieboldii prefers loose, fertile soil rich in organic matter, with pH preferably neutral or slightly acidic. It is intolerant of strong light and afraid of drought, so the main production areas in Northeast China mostly choose understory cultivation; when using old ginseng land or farmland for planting, a shade shed must be built. Understory cultivation has strict requirements for tree species, but broadleaf forest is best, mixed coniferous-broadleaf forest second. Slope aspect is best east or west, and slope preferably within 10 degrees.
Land preparation should be carried out in spring and summer; early land preparation helps soil maturation, making Asarum sieboldii grow well with light disease. Before digging, remove small shrubs or overly dense branches in the forest land to maintain 50%-60% light transmittance under the forest. Dig to a depth of 15-20 cm, remove stones and tree roots, rake the soil surface level, and make high beds 1-1.2 m wide, 10-20 m long, and about 20 cm high; the working path is 50-100 cm wide. Where the soil layer is thick, the working path can be slightly narrower; where the soil layer is thin, the working path should be wider, to ensure the bed surface has sufficient total amount.
2. Propagation methods Mainly seed propagation, but also root division propagation.
1) Seed propagation The seed treatment method is to dig a shallow pit in a shady place under the forest, about 15 cm deep, size depending on the amount of seed, mix 1 portion of seed with more than 5 portions of sand and place in the pit, cover with about 5 cm of sand, then cover with leaves or rice straw. Check frequently, pay attention to keeping warm and not waterlogged; after about 45 days, sow in time to avoid germination.
Sowing methods: broadcast sowing, drill sowing, and hole sowing are all acceptable. For broadcast sowing, mix the seed with 10 times fine sand or soil and scatter on the bed surface, sowing about a few grams of seed per square meter. For drill sowing, make rows on the bed at 10 cm row spacing, sowing width 4 cm, sowing about 130 seeds per row. For hole sowing, row spacing 13 cm, hole spacing 7 cm, sowing 7-10 seeds per hole. After sowing, cover with humus soil or sieved fine soil, about 2.5 cm thick, then cover with grass or leaves about 3 cm. Keep the soil moist.
Asarum sieboldii can be direct-sown and grown in place for 3-4 years before harvesting the product. This can be adopted when seeds are abundant. At present, production areas, in order to fully utilize seeds and expand planting area, mostly use seedling transplanting. Transplanting 2-3 year old seedlings is best, carried out in late autumn or early spring each year after the aboveground part withers or before the seedlings move. The planting method is to open horizontal furrows on the bed with sufficient basal fertilizer applied, row spacing 17-20 cm, plant spacing 7-10 cm, place the seed roots well in the furrow, let the roots spread out, cover with soil to a thickness such that the bud scales are about 5 cm from the soil surface, and cover with grass or leaves on top. It can also be planted by digging holes at 15 cm row spacing, planting 7-10 holes per row.
2) Root division propagation Using harvested plants, cut off a 4-5 cm long section from the upper part of the rhizome; each section must have 1-2 bud scales and retain root strips, then dig holes at 20 cm x 20 cm plant and row spacing, planting 2-3 rhizome sections per hole.
3. Field management
1) Watering and weeding Asarum sieboldii has a shallow root system and is not tolerant of drought, especially in seedling beds, where the seeds are tiny and the soil cover is shallow; soil moisture must be checked frequently, and watered promptly when the soil is dry, to ensure full and vigorous seedlings. Attention should be paid to timely weeding; there should be no weeds on the bed or in the furrows.
2) Regulating light Before May, temperatures are low, and Asarum sieboldii seedlings require relatively more light, so shading is not needed. From June onward, light should be controlled at 50%-60% transmittance; when using old ginseng land to plant Asarum sieboldii, a shade shed must be built well, and for interforest cultivation, sheds should also be added or branches trimmed according to the light requirements of Asarum sieboldii.
3) Fertilizing and earthing up Asarum sieboldii is a fertilizer-loving plant; when planted in poor soil, if not fertilized, it grows extremely slowly. According to experience in Liaoning, pigpen manure is best for basal fertilizer, smoked soil fertilizer (tiger manure) second, and superphosphate is good as chemical fertilizer. In May and July each year, superphosphate 1 kg can be mixed with 50 kg clear water, stirred and dissolved, then the supernatant taken and poured onto the bed surface with a watering can, using superphosphate 1 kg per 20 sq m.
After winter begins, use pigpen manure 4000 kg per mu mixed with superphosphate 40 kg for fermentation together, then mix the fermented fertilizer with about 5 times humus soil and spread it over the Asarum sieboldii bed, which both serves to fertilize for the coming year and protects the bud scales for safe overwintering. Because the rhizome of Asarum sieboldii grows upward one node each year, if its bud scales are not protected, they are prone to frost damage.
4) Removing flower buds Perennial plants bloom and set seed every year, consuming a large amount of nutrients and affecting yield, so except for seed-saving plots, all flower buds should be removed when they emerge from the ground.
4. Pest and disease control
1) Disease control Asarum sieboldii has relatively few diseases; at present the more serious damage is from sclerotinia, which occurs from early spring to summer each year and damages the whole plant. Control methods: strengthen field management, no water accumulation or hardening in the bed, pay attention to ventilation, and adjust light to 50%-60% transmittance. Harvest in good time or change land for planting. For chemical control, use 50% carbendazim 500-1000 times solution to spray leaves or drench roots. When diseased plants are found, they should be thoroughly removed, and lime should be scattered in the diseased holes or 5% formalin used for soil disinfection.
2) Pest control The main pests are cutworms, black hairy caterpillars, locusts, and Asarum sieboldii swallowtail butterflies, etc. Black hairy caterpillars, locusts, and Asarum sieboldii swallowtail butterflies bite and eat leaves; in severe cases most leaves are eaten. Cutworms cause the most serious damage, biting young buds and cutting off petioles and rhizomes. Cutworms can be controlled by mixing trichlorfon with fried fragrant soybean cake or wheat bran to make poison bait for trapping and killing, or by using poison soil. Other pests can be controlled by spraying the leaf surface with trichlorfon 1000 times solution.