How is Amomum villosum cultivated? A detailed guide to the cultivation techniques of the Chinese medicinal herb Amomum villosum
Planting techniques:
1. Site selection and land preparation
For the seedling nursery, choose newly cleared land with good shade conditions and convenient drainage and irrigation, preferably moist, fertile, loose sandy loam. For the transplant site: in mountainous areas, choose evergreen forest land on both sides of valleys and stream gullies, preferably with a south- or southeast-facing slope; in plains, choose land with drainage and irrigation conditions, avoiding heavy clay. Appropriate environmental selection favors nesting and reproduction of pollinating insects such as nomia bees (Nomia spp.), providing good conditions for pollination and fruit set.
The seedling nursery should be cleared 1 month before sowing to allow the soil to fully mature, then plowed before sowing, leveled, harrowed fine, and made into beds. The transplant site needs to be cleared 1 month before planting: cut down weeds and low shrubs, retain a certain number of shade trees, and replant where they are lacking. In mountainous areas, terraces should be built according to the terrain and topography, with full reclamation; in hilly and plain areas, plow and make beds about 2 m wide, with drainage and irrigation ditches at regular intervals. Trees around the transplant site should be retained, and where insufficient, replanted; some fruit trees that flower and fruit earlier than Amomum villosum can be planted to attract pollinating insects.
2. Propagation of planting material
2.1 Seed propagation: mostly used for variety improvement; it can produce a large number of seedlings in a short time, but they must be planted the following year and flower and fruit 1 year later than plants from division propagation.
Seed selection and seed treatment: From high-yielding populations, select mature fruit spikes or fruits that bear many fruits, have large grains, and are free of pests and diseases as seed. Place the selected fresh fruits in relatively soft sunlight for 2-3 hours each day, for 2 consecutive days, then peel off the fruit skin, add an equal amount of fine sand and a small amount of clean water, and pound and rub until a distinct aroma appears, then rinse away impurities with clean water, take out the seeds, dry them slightly, and sow.
Sowing: Generally sown in autumn. After seed collection, sow at the end of August or the beginning of September of the same year, and seedlings can be transplanted and established before May-June of the following year. If sowing in spring of the following year, the seeds need to be stored in damp sand. The germination rate of spring sowing is relatively low. Sow by dibbling or drilling at a plant-row spacing of 7×13 cm, cover with 0.5-1 cm of fine soil after sowing, then cover with a layer of Dicranopteris fern or thatch to help preserve soil moisture and prevent rain from washing away the seeds.
Field planting: Field planting is generally best in April-May. For planting in August-September, attention should be paid to watering. When planting, it is best to take seedlings from nearby, cut off about 2/3 of the leaves on the lower part of the plant, and plant immediately after cutting. If seedlings must be transported over long distances, they should be kept in a shady, moist place and watered frequently to prevent wilting. For field planting, generally dig holes at a plant-row spacing of 0.6-1 m, with hole depth and diameter of 30 cm each, apply decomposed organic fertilizer such as human and livestock manure, cover with 6-7 cm of soil after planting, let the tips of new stolons emerge above the soil surface, firm the base by treading, and keep the hole surface lower than the ground. Generally, 400-1500 seedlings are used per mu. After planting, cover the hole surface with grass, and in dry weather, water or irrigate promptly.
2.2 Division propagation: It is best to select young seedlings bearing 1 or 2 newly sprouted stolons as planting material, as they have a strong ability to produce tillers. Strong old seedlings can also be used as planting material. In some areas, the method of "growing seedlings from seedlings" is used to propagate planting material, that is, first raise seedlings from seed, then plant them in a seedbed, and the following year dig up the tiller seedlings from the seedbed for field planting. The planting method is the same as for seedling-grown plants.
3. Field management
3.1 Seedling stage management: After sowing, water according to weather conditions to keep the seedbed moist. After the seeds germinate, set up movable shade frames in time, about 1 m high, with 70-80% shade, and remove the covering grass on the seedbed. When the seedlings grow 4-5 leaves, combine weeding with fertilization, frequently applying dilute decomposed human manure and urine. Before overwintering, apply decomposed cow dung, plant ash, etc. In areas with low winter temperatures, windbreak frames should be set up in windy places. After the seedlings grow 7 leaves, gradually reduce the shade level to harden the seedlings, but it must not be less than 50%.
3.2 Replanting and stem cutting: After field planting, replant promptly where seedlings are missing to ensure a sufficient population. To improve ventilation and light penetration, reduce nutrient consumption, ensure robust plant growth, prevent flower and fruit rot, and increase the fruit-setting rate, cut stems at the appropriate time according to the overall growth of the population. During the flowering and fruit-setting period, less stem cutting is appropriate; for populations that have fruited for many years and are declining, more stem cutting is appropriate, which helps renewal and rejuvenation. Usually, stems are cut twice a year; the first cutting should be light to favor flowering and fruiting. In mid-to-early February, cut off dead and diseased stems about 10 cm above the ground and burn them in a centralized manner. The second cutting should be heavier to favor the growth of new seedlings. In August-September, cut off dead and diseased stems as well as old or weak seedlings with only 6-8 leaves. Generally, in mountainous areas, keep 25,000 plants per mu, and in hilly and plain areas, keep about 30,000 plants per mu.
3.3 Weeding, drainage and irrigation, and topdressing: In the first 1-2 years, weed frequently; after flowering and fruiting, weed twice a year and spread the cut weeds over the ground. After heavy rain, drain accumulated water promptly. Where conditions permit, irrigate at the appropriate time. According to analysis, Amomum villosum plants require the most potassium, accounting for 58.42-79.04%, followed by nitrogen, and the least phosphorus. Generally, fertilize in February-March, mainly with phosphorus and potassium fertilizers, such as superphosphate, plant ash, burned soil, organic fertilizer, etc., which favors flower bud development; in April-May during the bud and flowering stage, apply more burned soil; in May-June during the young fruit formation stage, apply fruit-preserving fertilizer; in August-September after fruit harvest and stem cutting, apply organic fertilizer, such as decomposed human and livestock manure and urine, farmyard manure, etc., to promote seedling growth, and at the same time do a good job of replanting to restore the population's vigor as soon as possible, promote flower bud differentiation, and create conditions for more flowering and fruiting the following year.
3.4 Earthing up and cold protection: Exposed stolons should be earthed up promptly. During autumn management, shade trees should not be thinned too much; before cold waves and frosts strike, cover the plants with rice straw and use smoke at the same time. In low-temperature dry winds, water or irrigate at the appropriate time and in the appropriate amount.
3.5 Regulating shade level: The shade level has a great influence on flowering and fruiting. When selecting suitable shade tree species, be sure to adapt to local conditions, use local materials, and consider comprehensively according to local factors such as tree species, altitude, and topography. At present, the shade trees widely used in production with relatively good results include Albizia chinensis, Macaranga denticulata, Macaranga sampsonii, red milk fruit, Saurauia tristyla, Schefflera octophylla, Acacia confusa, etc. In Gaozhou, Guangdong, and other places, economic crops such as lychee, mango, Canarium pimela, and banana are also used with good results. When clearing mixed forests, retain leguminous tree species and other evergreen tree species with small leaves, sparse branches and leaves, open crowns, and deep roots. If artificial afforestation is needed, first plant banana and Tephrosia candida, then plant long-term shade trees.
3.6 Artificial supplementary pollination: Because of the special morphological structure of Amomum villosum flowers, there are very few insect species that can pollinate them well. Therefore, in places lacking pollinating insects, especially in newly planted areas, the natural fruit-setting rate of Amomum villosum is very low. At present, artificial supplementary pollination is an effective way to increase yield. Two methods are commonly used in production.