How is large-scale cultivation of Dendrobium officinale carried out? A detailed explanation of the methods
Dendrobium officinale (scientific name: Dendrobium officinale Kimura et Migo): stems erect, cylindrical, 9-35 cm long, 2-4 mm thick, unbranched, with many nodes; leaves distichous, papery, oblong-lanceolate, margins and midrib often tinged with pale purple. Racemes often emerge from the upper part of the old leafless stems, bearing 2-3 flowers; floral bracts dry membranous, pale white, ovate, 5-7 mm long; sepals and petals yellow-green, nearly similar, oblong-lanceolate; lip white, with 1 green or yellow callus at the base, ovate-lanceolate, slightly shorter than the sepals, reflexed in the middle. Column yellow-green, about 3 mm long, with 1 purple dot on each side at the apex; anther cap white, long ovate-triangular, about 2.3 mm long, apex nearly acute and 2-lobed. Flowering period March-June.
Because Dendrobium officinale has good pharmacological effects, wild Dendrobium officinale has been over-harvested by local villagers for a long time, and wild Dendrobium officinale itself has a long growth cycle. Therefore, relying solely on naturally growing Dendrobium officinale cannot fully meet the needs of the social market, and the use of batch cultivation is particularly important, and its cultivation techniques have received attention from all sectors of society.
How is large-scale cultivation of Dendrobium officinale carried out?
Selection of planting materials
To carry out batch cultivation of Dendrobium officinale, the selection of planting materials cannot be overlooked. Whether the planting materials are selected well or not directly determines whether Dendrobium officinale can grow normally. Under normal circumstances, batch cultivation of Dendrobium officinale mainly uses tissue-cultured seedlings, and the proliferation culture generation should be selected at generations 6-8, so that the offspring crops can grow better and the product quality can be improved.
There are corresponding index parameters for Dendrobium officinale tissue-cultured seedlings, such as high-quality grade: crop height above 5 cm, number of crop leaves above 4, crop stem thickness above 0.3 cm, crop root number preferably 3-5, and crop leaf color preferably dark green. Qualified grade: crop height about 2-5 cm, number of crop leaves 2-4, crop stem thickness above 0.2 cm, crop root number mainly 2-3, and crop leaf color tender green.
Selection of planting substrate
Dendrobium officinale is one of the orchid family plant varieties. It mainly relies on mycelium for the absorption of water and inorganic substances, and collects organic nutrients such as glucose and amino acids through the decomposition by symbiotic fungal hyphae of attached moss and bark and other organic combinations. Because of its unique growth mode, Dendrobium officinale has strict requirements for the growth substrate. If the planting substrate is not selected appropriately, it may affect the healthy growth of Dendrobium officinale, and in severe cases may cause all of it to die.
At present, there are many choices for its substrate, and different combinations give the crop different quality. Among them, the following several all have corresponding planting effects:
The first combination is peat soil plus coconut coir;
The second combination is wood blocks plus moss;
The third combination is sawdust plus pine bark.
Because the following 3 substrate combinations each have their own characteristics, this article, on the basis of drawing on their advantages and in combination with local conditions, selects a substrate best suited to the growth of Dendrobium officinale. A ratio combination of 5:3:2 is used for pine bark plus coconut coir plus peat soil. After the mixed substrate undergoes a series of treatments (such as composting, boiling, and high-temperature disinfection), laying it at a thickness of 10-15 cm is optimal.
Planting management
1. Fertilization management
After Dendrobium officinale is planted, its later-stage planting management is equally important. Fertilization management, as an indispensable step in the later growth of Dendrobium officinale crops, mainly uses a combination of organic minerals and foliar spraying. After the crop sprouts and grows leaves, and the leaves gradually turn green, part of the crop's new roots may be exposed to the air and need to be covered with substrate. At the same time, at this stage, semi-decomposed cow dung can be used to fertilize the crop.
At present, its main fertilization process is roughly as follows: first, foliar fertilizer is applied by spraying, mainly for crops 7 d after planting; then, according to the actual situation of the crop, farmyard manure is applied each time, preferably about 50-100 kg/667 m²; in mid-to-late October, potassium dihydrogen phosphate is applied once, and about 20 kg/667 m² is more appropriate; after the beginning of spring the following year, farmyard manure is applied once again, with 50-100 kg/667 m² being most appropriate.
2. Pest and disease control
During the growth process, Dendrobium officinale is often attacked by pests and diseases. Therefore, correct and timely control can reduce the damage of pests and diseases to the crop. Dendrobium officinale mainly has the following diseases: root rot, black spot, and anthracnose, etc. Different control measures are taken for different diseases. For example, root rot mainly occurs in rainy seasons, first causing its roots to rot, and then slowly causing the upper part to wither; its corresponding control method: before planting the crop, soak the species with 25% carbendazim 100-fold wettable powder for an appropriate time.
Black spot mainly prevails under conditions of low temperature and rain, and its main harm lies in the crop's leaves and leaf stalks, thereby causing the leaves to wither; its corresponding control method: use 51% carbendazim 1,000-fold solution to spray Dendrobium officinale. Under normal circumstances, spraying 1-2 times can basically control it. The main harm of anthracnose lies in the leaves and fleshy stems. When the leaves first develop the disease, they appear black, and later slowly cause the entire leaf to scorch and fall off, finally leading to the death of the crop; its corresponding control method: in the early stage of the disease, it can be removed by pruning, or a 1:1:200-fold Bordeaux mixture can be used to spray the crop for control.
Harvesting
The best time to harvest Dendrobium officinale is about 2-3 a after planting, and the most suitable harvest time is in the 3rd a. Under normal circumstances, the harvesting principle adopted is to “remove three and keep two”, that is, stems of Dendrobium officinale that are 3 a or more are harvested, and stems below 3 a are reserved for later propagation and growth. After harvest, attention should be paid to promptly spraying protective fungicides to prevent the occurrence of disease.