Gastrodia: Low-Altitude Substitute-Material Cultivation Method for a Precious Chinese Medicinal Herb
Gastrodiais a rare and precious Chinese medicinal herb. In the past it relied on wild sources, growing in mountain forests above 500 m in elevation, and was extremely scarce and difficult to dig up; it now faces extinction. The development of artificial cultivation of gastrodia has saved this precious species, but technically it still cannot break away from cultivation in high-altitude areas, and the raw material cannot be separated from log segments (oak). This makes gastrodia cultivation greatly limited by region. Second, it is limited by the felling of forest resources. These two major drawbacks have long plagued the development of gastrodia, and it has never been possible to achieve modernized, standardized cultivation of gastrodia.
This method addresses the shortcomings of the above existing techniques. Through long-term research and experimentation, we have worked out a new cultivation method for gastrodia that is not limited by regional altitude or raw materials. In areas below 300 m in elevation, it can use straw and corn cobs to cultivate Armillaria and produce high-yield, high-quality gastrodia. Through improvements in elite variety selection and breeding, cultivation environment, cultivation materials, substrate formulation, and cultivation methods, low-altitude substitute-material cultivation of gastrodia has been achieved. The specific contents are introduced as follows:
1. Material selection and treatment: To cultivate gastrodia, Armillaria must first be well cultivated. In the past, Armillaria was mainly cultivated with log segments (oak species). With the protection of ecological balance, the state prohibits the felling of forests, so the raw materials for cultivating Armillaria with log segments have been affected. In order to find a way out, we conducted experiments with straw, and after repeated exploration and practice, it has been proved that whole corn cobs are the ideal material for cultivating Armillaria.
There are certain special requirements for materials used to cultivate Armillaria with substitute materials. Corn cobs may be used either dry or fresh, but whole kernels that are free of mildew and rot are best. If fresh corn cobs cannot be used in time, they must be placed under the sun to dry thoroughly before they can be stored. Otherwise, if there is moisture, they will become moldy during storage. In particular, green mold and yellow mold are very likely to occur and will affect the growth of Armillaria in the future. If any moldy ones are found, they must be picked out, or quicklime water may be sprayed on them, or they may be soaked to eliminate the mold. However, when used, they must be rinsed with clean water to avoid excessively high alkalinity affecting the growth of Armillaria.
2. Selection of gastrodia seed: The quality of gastrodia seed is very closely related to gastrodia yield. There are two sources of gastrodia seed: one is sexual reproduction; that is, after gastrodia completes its physiology, it bolts, flowers, and sets seed, producing pollen seed, or pollen seed after artificial cross-pollination. After 3-5 months of cultivation with germination fungi and Armillaria, pollen seed can be dug out as first-generation seed the size of a peanut, called "zero-generation seed," also known as the hybrid seed of sexual reproduction. This variety is conducive to high and stable yields of gastrodia. In particular, after distant hybridization from wild black-stem and red-stem gastrodia, the selected "TC828 variety" has become the first-choice high-yield variety for current gastrodia cultivation.
The other is asexually propagated gastrodia seed, namely the small gastrodia seed that appears each time gastrodia is harvested. This small gastrodia is then cultivated again, and after one year it becomes commercial gastrodia. The continuous cyclic cultivation of small gastrodia is called an asexually propagated variety, but after 3-4 years of asexual reproduction, degeneration is likely to occur. Whether degeneration is fast or slow is related to environmental conditions and techniques. In order to achieve high quality and high yield in gastrodia, it is best to choose sexually hybridized gastrodia seed.
3. Selection of cultivation site: In the past, gastrodia generally grew in mountain forests at 500-1500 m in elevation, with areas at 800-1200 m being more suitable. Later, artificial cultivation also selected these high-altitude mountain forests. The main reason is that gastrodia belongs to the medium- and low-temperature varieties and is afraid of high temperatures. To solve this problem, in addition to selecting and breeding gastrodia seed and domesticating varieties with higher temperature adaptability, the key is to take corresponding measures in the selection of cultivation sites and artificial cooling so that gastrodia cultivation in low-altitude areas can be fully achieved.
Low altitude refers to plain areas below 300 m. Cultivation can be carried out in cool indoor spaces, outdoors under forest, or under artificial shade sheds. A site should be chosen that avoids both direct sun exposure and flood scouring. A shady, moist slope with good drainage is best. In terms of environment, it is best to have large areas of natural shade forest or artificial shade forest. As for soil quality, fertile, relatively loose, breathable soil that does not easily become compacted is suitable. Sandy soil or humus soil may also be used. The soil moisture content should be between 50%-60%. A soil moisture level at which soil forms a ball when squeezed by hand and scatter immediately when dropped is suitable. Clay or compacted soil is generally not suitable.
4. Cultivation of Armillaria: There are many kinds of Armillaria. Not all Armillaria are suitable for gastrodia growth, and not all those that can be suitable for gastrodia growth are superior Armillaria varieties. Armillaria also differ in quality. Only high-quality Armillaria can grow together with gastrodia and be nutritionally complementary. At present, the superior Armillaria variety "XB-9" has been selected from several Armillaria varieties. It is most compatible with the superior gastrodia variety "TC828" and is the foundation for high-yield cultivation of gastrodia at low altitude.
Cultivating Armillaria with corn cobs has the advantages of abundant raw material sources, low cost, fast growth, and good results. The shortcoming is that it can only be used for one year and must be replaced every year, unlike log-segment Armillaria, which can be used for 2-3 years. The method for cultivating Armillaria with corn cobs is: first soak the corn cobs in water for 12-24 hours (they must be thoroughly soaked), take them out and drain off the excess water, first spread a layer of corn cobs on the ground about 10 cm thick, sprinkle on Armillaria mother culture, using 750 g/bottle per square meter, then spread a second layer of corn cobs, sprinkle on Armillaria spawn again, and in the same way add a third or fourth layer, then cover with soil 10-15 cm and let it spawn. Another method is to spread each layer of corn cobs, sprinkle on Armillaria spawn, fill the gaps between the corn cobs with fine soil, then spread the second layer of corn cobs, sprinkle on Armillaria spawn, and fill the gaps between the corn cobs with fine soil; generally no more than four layers.
After cultivation at 18°C-22°C for 2-3 months, the Armillaria rhizomorphs run through the entire corn cob material, and it can then be used for gastrodia cultivation. If there is not enough Armillaria material, Armillaria can also be expanded and cultivated further. This method is to add uncultivated corn cobs to corn cobs that have already been cultivated with Armillaria, in a ratio of 50% each, with the same operation as above, and finally cover with soil to spawn. This method is simple and easy to carry out and does not require mother culture. As long as it is not affected by high temperature, pests, or diseases in the environmental conditions, causing Armillaria degeneration or variation, it can be used in long-term cyclic use.
5. Cultivation method for gastrodia: Low-altitude cultivation of gastrodia may be carried out indoors or outdoors, and the cultivation method is basically the same. First spread a layer of loose soil 10 cm thick and 1 m wide on the ground, place the corn cob fungal material on it, and spread it flat on the soil. Each layer of corn cobs should be spaced 10-12 cm apart. Then place one small gastrodia on the left and right of each corn cob. The distance between small gastrodia should preferably be 10 cm, and they should not be too sparse or too dense. After the gastrodia is planted, immediately cover with soil 10 cm thick, then continue to plant the second layer in the same way, and finally cover with soil 15 cm thick, then compact the soil surface and around the edges. Make one box 1 m wide, leave a walkway in the middle, and the length is unlimited and can be determined according to the site. After planting, the height is generally between 30-35 cm. The sides of the box may be retained with bricks or left exposed. In short, it must not be too wide: first, for ease of management, and second, to facilitate ventilation for gastrodia growth.