Detailed Explanation of the Key Points of Artificial Cultivation Techniques for Asarum heterotropoides
Asarum heterotropoides, the whole plant can be used as medicine, mainly containing essential oil, asarone, palmitic acid, asarum alkali, methyl eugenol and other components. It is a good medicine for dispelling wind-cold and promoting the movement of water qi, with effects such as pain relief, sedation, sweating, and phlegm removal. It is also used to extract insect repellent.
Biological Characteristics
Asarum heterotropoides seeds have a short lifespan. After sowing, germinated seeds can quickly take root, but they do not emerge from the soil that year; they must wait until the spring of the 2nd year to sprout. Naturally matured seeds have embryos that are not yet fully mature and require 45 ~ 60 days of after-ripening in soil or sandy soil with a moisture content of 30% ~ 70% before they can germinate. Asarum heterotropoides is a shade-loving plant and is afraid of direct midday sun in summer, so shading must be provided when cultivated on flat land. However, excessive shading is also detrimental to its growth. According to observations, before May 20th (Xiaoman), no shading is needed; after late May, shading must be provided. Asarum heterotropoides grows well in slightly acidic or neutral soil with high humus content, and it requires moist, loose soil with good drainage.
Cultivation Techniques
Land Preparation
For artificial cultivation of Asarum heterotropoides, select plots in front of or behind houses or with fertile soil, high organic matter content, no water accumulation, and convenient management and guarding, because Asarum heterotropoides has a relatively long life cycle, requiring at least 5 years from planting to harvest and sale of large goods. Therefore, it is necessary to manage both the Asarum heterotropoides and the materials, and a fence or courtyard wall must be built to prevent damage from nature and humans and livestock.
Soil Preparation, Fertilization, and Bed Making
After the Asarum heterotropoides plot is selected, soil preparation, fertilization, and bed making should be carried out before planting. First remove the stubble of the previous crop, apply 2 000 kg of fully decomposed high-quality manure per mu, spread it evenly, then deep plow 20 cm, make beds 1.2 m wide, with a length of 15 ~ 20 m or depending on the terrain, leaving a 30 cm wide walking path ditch.
Seedling Raising
The method for making the sowing bed is the same as for the planting bed. Sowing methods include drilling and broadcasting. For broadcasting, sow 150 g per square meter, cover with 1 cm of sifted humus soil, then sprinkle a layer of dry leaves or spread a thin layer of rice straw on top to keep the seedbed moist. For drilling, open furrows at horizontal intervals of about 10 cm, with a furrow depth of 2 ~ 3 cm, sow 75 ~ 100 g per square meter, cover with 1 ~ 1.5 cm of soil, and also cover with dead leaves or rice straw on top. In the spring of the 2nd year after sowing, Asarum heterotropoides begins to emerge. Shading must be carried out from the beginning of emergence, and frequent hoeing and loosening of the soil should be done. By the autumn of the 3rd year, planting can be carried out.
Planting
Planting Time
Planting can be done in both spring and autumn. In spring, carry it out in mid-to-late April when the buds have not yet sprouted. In autumn, carry it out from late September to early October.
Planting Density
After making the planting bed, plant at a spacing of 20 cm ×20 cm. To harvest one year earlier, when seedlings are sufficient, the density can be increased by planting at a spacing of 20 cm ×10 cm. Dig furrows 10 cm deep, and plant 2 ~ 3 plants per hole. When planting, spread the root system, lift the seedlings upright, place the rhizome (bud) 3 cm below the soil surface, press firmly, then water, and after the water settles, earth up and close the hole. Then, scatter a layer of half-decomposed dead branches and fallen leaves or chopped rice straw between the plants and rows to prevent heavy rain from washing away the bed surface and sun exposure from causing hardening.
Planting
When planting during the growing season, place rice straw under the leaves after planting to prevent the leaves from being burned by high temperatures on the soil surface, which would cause the leaves to dry up and rot. Planting, watering, and shading should be done together to prevent the leaves from drying up and to shorten the recovery period. Once the leaves of Asarum heterotropoides seedlings dry up, new leaves cannot develop that year, causing the entire plant to die from failure to produce leaves, resulting in missing plants and broken rows.
Field Management
Building Shade Structures
There are currently 2 shading methods. One is to build a frame with wooden poles and cover it with corn stalks. The frame is as wide and as long as the bed, with a height of 80 cm. The other is to use steel wire or bamboo strips to make an arched frame at intervals of 2 m, covered with black plastic shade netting. The light transmittance of the shade netting and corn stalks should be adjusted according to the season and the age of the Asarum heterotropoides seedlings. In the 1st ~ 2nd years after planting, the seedlings are small and the canopy density is poor, so a light transmittance of 40% is suitable. After 3 years of planting, the seedlings are larger and the canopy density is high, so the light transmittance should be appropriately greater, with 50% being suitable. To increase the irradiation of scattered light in the morning and evening, when using plastic shade netting, leave 20 ~ 30 cm uncovered at the lower corners.
Fertilization and Irrigation
Asarum heterotropoides is a perennial herbaceous plant that grows very slowly. It can only be harvested 4 ~ 5 years after transplanting. To make Asarum heterotropoides grow quickly and achieve high yield, sufficient base fertilizer must be applied, and before freezing each year, topdressing manure should be applied over the surface, and irrigation should be carried out during dry weather.
Loosening Soil, Hoeing, and Earthing Up
During the growth process of Asarum heterotropoides, soil should be loosened and weeds hoed 3 ~ 4 times each year. After irrigation, soil should be loosened in a timely manner to prevent the bed surface from cracking. While loosening soil and hoeing weeds, the beds should also be tidied and soil earthed up.
Overwintering Management
In autumn before freezing, after the leaves of Asarum heterotropoides dry up, the shade netting can be removed, and in combination with autumn fertilization, apply "surface manure" 1 ~ 2 cm thick and earth up for cold protection.
Seed Harvesting and Storage
After planting, Asarum heterotropoides begins to bloom and bear fruit in the 3rd year, and seeds can be harvested. Asarum heterotropoides seeds mature in early June, and the mature fruits naturally split open, causing the seeds to fall to the ground. Harvest in stages when the fruit surface changes from green to white, the fruit flesh is powdery, that is, when the fruit feels slightly soft when pinched by hand and is about to split, and the seeds have not yet fallen off. After harvesting, rub off the seed coat, wash out the seeds with clean water, and sow immediately. If sowing cannot be done temporarily, mix the seeds evenly with 5 times their volume of fine sand, maintain 30% ~ 50% moisture, and sow after 45 days of after-ripening.
Harvesting and Processing
Asarum heterotropoides can be harvested 4 ~ 5 years after planting. Harvesting is generally carried out during the peak growth period from late July to mid-August. During harvesting, use a pickaxe to dig out the whole plant, shake off the soil, and do not wash with water in order to preserve the aroma of the roots. Dry by baking or place in a ventilated and cool place to air-dry, then it can be stored in a warehouse or sold.
Precautions
The spacing of the arched frame for the shade netting must not exceed 2 m, and it should be fixed in a tunnel shape to prevent the shade netting from being damaged by strong winds and losing its shading function.
In the early stage of planting, when the Asarum heterotropoides seedlings are small, field weeds should be removed in a timely manner to prevent the seedlings from being overwhelmed.