Detailed Explanation of the Key Technical Points for Cultivating and Planting Astragalus membranaceus
MongoliaAstragalus membranaceusAlso known as Astragalus membranaceus, it is a perennial herb, 40-150 cm tall or slightly more, with a straight, long, cylindrical main root, 25-75 cm long, slightly woody, the root crown 1.5-3 cm in diameter, and the surface pale brownish-yellow or dark brown. The stem is upright, much branched, and covered with long soft hairs. Odd-pinnate compound leaves, alternate; the base of the petiole has lanceolate stipules, about 6 mm long; 25-37 leaflets, the leaflets broadly elliptic, 4-9 mm long, the apex somewhat obtuse with a short mucro, the base cuneate, entire, with white long soft hairs on both surfaces. Racemes axillary, with 10-25 flowers, loosely arranged; the pedicels short, bearing black stiff hairs; bracts linear-lanceolate; the calyx tubular, about 5 mm long, with 5 calyx teeth and long soft hairs; the corolla yellow, papilionaceous, less than 2 cm long, the standard triangular-obovate, without a claw, the apex slightly emarginate, the wings and keel both with long claws; stamens 10, diadelphous; the ovary stalked, smooth and hairless, the style hairless. The pod membranous, inflated and air-filled, ovate-oblong, 11-15 mm wide, the apex beaked, with obvious reticulate veins. Seeds 5-6, kidney-shaped, black. Flowering period June-July, fruiting period August-September.
Cultivation Techniques for Astragalus membranaceus
Astragalus membranaceus is a perennial herbaceous plant of the Fabaceae family. Its dried root is used as medicine, and the medicinal name is Huangqi; it has the functions of tonifying qi and consolidating the exterior, promoting diuresis, drawing out toxin and discharging pus, and promoting tissue regeneration.
1 Botanical Characteristics and Environmental Requirements
1.1 Botanical Characteristics
The main root is long and robust, the stem upright, 40-80 cm tall. Odd-pinnate compound leaves, with 12-18 pairs of leaflets; the leaflets broadly elliptic, elliptic or oblong, with short stalks, the leaf 5-10 mm long and 3-5 mm wide, both ends nearly rounded, hairless above and covered with soft hairs below; stipules lanceolate. Racemes axillary, bearing 5-20 flowers; the calyx bell-shaped, densely covered with short soft hairs, with 5 calyx teeth; the corolla disc-shaped, yellow to pale yellow, 18-20 mm long, the standard oblong-obovate, the wings and keel both with long claws; 2-body stamens; the ovary smooth and hairless, the pod membranous, inflated, semi-ovate, the apex with a short beak, the base with a long ovary stalk, all hairless. Flowering period June-July, fruiting period July-September.
1.2 Environmental Requirements
It likes sunlight, is drought-tolerant, fears waterlogging, likes a cool climate, has strong cold resistance, and can tolerate low temperatures below -30°C; it fears heat and has strong adaptability. It mostly grows on dry, sunny grasslands in mountainous or semi-mountainous areas at an altitude of 800-1300 m, or among tree clusters at sunny forest edges; the vegetation is mostly coniferous-broadleaf mixed forest or mountain miscellaneous woodland; the soil is mostly mountain forest soil. It is unsuitable for continuous cropping, and should not be continuously cropped with potato, chrysanthemum, Atractylodes macrocephala, etc.
2 Cultivation
2.1 Site Selection and Land Preparation
Astragalus mongholicus is a deep-rooted plant. For flatland cultivation, a high-lying, well-drained, loose and fertile sandy loam should be selected; for mountainous areas, deep soil, well-drained, wind-sheltered and sunny hillside land or wasteland should be selected for planting. After selecting the land, carry out land preparation, with autumn plowing being preferable. Generally, the plowing depth is 30-45 cm, and base fertilizer is applied together with plowing, applying 2000-2500 kg of farmyard manure and 25-30 kg of superphosphate per mu; for spring plowing, attention should be paid to soil moisture conservation, then rake fine and level, and make beds and ridges, generally with a ridge width of 40-45 cm and a height of 15-20 cm.
2.2 Seed Treatment
2.2.1 Warm water seed soaking After spring rain, immediately place Astragalus mongholicus seeds in a container, add an appropriate amount of boiling water and stir continuously for about 1 minute, then add cold water to adjust the water temperature to 40°C, leave for 2 hours, pour out the water, cover the seeds and keep them sealed for 8-10 hours; when the seeds swell or the outer coat cracks, they can be sown after rain.
2.2.2 Sand grinding Place dry seeds together with dry fine sand amounting to 2/3 of the seed volume on a stone mill and grind them, turning them while pressing; when the seed coat has been ground from brown-black to gray-brown, they can be sown. In production, combining the 2 methods is better.
2.3 Direct Seeding
Sowing can be done in the 3 seasons of spring, summer and autumn. In spring, sowing can be done when the ground temperature reaches 5-8°C; keep the soil moist, and seedlings emerge in about 14 days; summer sowing is carried out in June-July when the rainy season arrives. If the soil moisture is sufficient and the temperature is high, seedlings can emerge 7-8 days after sowing; autumn sowing is carried out when the ground temperature is stable at 1-6°C.
The sowing method adopts drilling or hole sowing. For drilling, the row spacing is about 20 cm, the furrow depth 3 cm, and the sowing rate is 2-2.5 kg per mu. When sowing, mix the seeds with methamidophos or pyrethroid pesticides to prevent underground pests, then after sowing cover with soil 1.5-2 cm and compact, and apply 8-10 kg of diammonium phosphate and 5-7 kg of potassium sulfate as base fertilizer per mu. From sowing to emergence, keep the soil moist or add mulch to promote emergence. For hole sowing, holes are mostly opened at a spacing of 20-25 cm, 5-10 seeds are sown per hole, covered with 1.5 cm of soil and leveled by treading, and the sowing rate is 1 kg per mu.
2.4 Field Management
2.4.1 Thinning and final thinning Thinning is carried out when the seedlings are 6-10 cm tall, after the appearance of 5 compound leaves. When the seedlings are 15-20 cm tall, final thinning is carried out at a plant spacing of 20-30 cm. For hole planting, final thinning is carried out at 1-2 plants per hole.
2.4.2 Loosening soil and hoeing weeds After the seedlings emerge completely, the first loosening of soil and hoeing of weeds can be carried out. At this time the seedlings are small and the roots shallow, so shallow hoeing should be the main method. Afterwards, hoe weeds 2-3 times according to field conditions.
2.4.3 Topdressing After final thinning, nitrogen fertilizer and phosphate fertilizer should be applied as topdressing, generally applying 15-17 kg of ammonium sulfate or 10-12 kg of urea, 7-8 kg of potassium sulfate, and 10 kg of superphosphate per mu. At the flowering stage, apply 6-10 kg of superphosphate and 7-10 kg of nitrogen fertilizer per mu to promote seed setting and seed maturation. On fertile plots, apply as little chemical fertilizer as possible.
2.4.4 Irrigation and drainage It "likes water yet fears water"; in management, attention should be paid to "irrigation and drainage". It has 2 peak water-demand periods, namely the seed germination period and the flowering and pod-setting period. During the seedling stage, irrigation should be small in amount and frequent; during the flowering and pod-setting period, water appropriately according to precipitation conditions. During the growing season's rainy period, attention should be paid to drainage at any time.
3 Harvesting and Processing
3.1 Harvesting
In terms of quality, 3-4 year old plants are the best. In current production, harvesting is generally done at 1-2 years, which affects the quality of the medicinal material; it is recommended to harvest at 3 years. Harvesting should be done during the dormant period and the sprouting period; at this time the content of the active ingredient astragaloside IV in Astragalus mongholicus is relatively high, so harvesting should be done in the two seasons of late April to early May and late October to early November. When harvesting, the aboveground part can first be cut off, and then the root dug out. Take care not to break the root, so as not to affect yield and quality.
3.2 Processing
For the dug-out roots, remove the soil, and when sun-dried to 70-80% dry, remove the lateral roots and fibrous roots, grade them, tie them into small bundles and then dry them in the shade. Those with thick and robust root strips, a pale yellow surface, a white outer layer in cross-section, a pale yellow center and a sweet taste are considered the best; the dried product is stored in a ventilated, dry place.