Detailed Explanation of Green Organic Cultivation Techniques for Changbai Mountain Shiitake Mushrooms
The edible mushroom industry is a very important development project. It is one of the three major industries of modern large-scale agricultural production (namely crop farming, livestock farming and edible mushroom cultivation). It is a green food on which humanity depends for survival and has enormous development potential.
Baishan City has dense forests, abundant rainfall and large day-night temperature differences, making it highly suitable for the growth and reproduction of edible and medicinal fungi, with shiitake mushrooms as the main type. By establishing a green (organic) shiitake mushroom production demonstration base, it is possible to further adjust the industrial structure of forestry and agriculture, enabling part of the forestry workers and farmers to separate from traditional logging and grain growing and engage in standardized production of green (organic) shiitake mushrooms. This can both develop the regional economy and help local farmers and idle social labor become wealthy, and it is also a broad path for accelerating the adjustment of the regional agricultural industrial structure.
I. Development Prospects of Green (Organic) Shiitake Mushrooms in Changbai Mountain
At present, in the major international shiitake mushroom consumption countries and regions, demand for fresh mushrooms is increasing day by day. However, as production increases, resources in the south are becoming increasingly depleted, and influenced by many factors such as climatic conditions and labor costs, shiitake mushroom production bases in the south are gradually shifting to the north. At present, the main shiitake mushroom production areas have shifted to various parts of Liaoning and Jilin. As far as Liaoning and Jilin are concerned, some have resources but no technology, and some have technology but no resources. Therefore, the development of shiitake mushroom production is constrained, and shiitake mushroom products far cannot meet the demand of domestic and international markets. Baishan City, however, has dense forests, with a forest coverage rate of 78%. Forest by-products such as treetops and branches are very abundant. It has superior natural conditions, strong technical capacity, low unit costs and excellent product quality. Green (organic) shiitake mushrooms in Baishan City have broad development prospects.
II. Cultivation Methods of Green (Organic) Shiitake Mushrooms in Changbai Mountain
(I) Production and selection of mushroom spawn.
Shiitake mushroom spawn is divided into mother spawn, stock spawn and cultivation spawn. The unit producing mother spawn must be a designated production unit with qualifications certified by the higher agricultural administrative department, having obtained a production license and possessing the corresponding technical level as a professional research unit. Ordinary cultivators can purchase stock spawn from these units and produce cultivation spawn for production.
A. Stock spawn: this is the granular spawn that we transfer from mother spawn.
1. Preparing the culture medium: first wash the glass bottles with limewater, then rinse them clean with clear water and dry them. Wash corn kernels clean and boil them until tender but not mushy, cool them, mix in a little sawdust culture medium, fill the bottles up to the shoulder, cover with a 1 cm thick layer of sawdust culture medium and press flat, then seal the opening with a cotton plug and cover with double-layer kraft paper. Place in an autoclave for sterilization, keep at a constant temperature under 1.5 kPa pressure for 1.5-2 hours, cool, and wait for inoculation.
2. Inoculation: place the bottles into a sterilized inoculation box, then put the surface-disinfected alcohol lamp, cotton plugs, inoculation spatula, inoculation rake, tweezers and matches into the box together, then seal the box, sterilize with an oxygen atom sterilizer for half an hour, and carry out inoculation. Inoculation means dividing the test-tube spawn into small pieces and placing them into the bottles, covering with cotton plugs, and culturing.
3. Culturing: place the inoculated spawn bottles into the culture room and culture at a constant temperature of 24+2°C and 24-2°C for 30-35 days, by which time the bottles will be fully covered.
B. The production of shiitake mushroom cultivation spawn mainly includes the process steps of ingredient mixing, bagging, sterilization, inoculation and spawn culture management.
1. Preparation of culture material
(1) Formula: (mixed sawdust culture medium formula) mixed sawdust 94%, bran 4%, gypsum 1%, sugar 1%, material-to-water ratio 1:1-1.2.
(2) Mixing the material: according to the formula, mix the dry materials of mixed sawdust, bran and gypsum evenly, then dissolve the sugar in water, add it to the dry materials and mix well. After leaving it for half an hour, when the material is held in the hand, a small amount of water seeps out between the fingers, which is sufficient; the water content reaching 60% is sufficient.
2. Bagging
(1) Selection of spawn bags: for normal-pressure sterilization, low-pressure polyethylene bags are often selected. They can withstand pressure below 0.1 MPa and have relatively poor transparency but good toughness. The commonly selected specification is 14 cm x 27 cm x 0.004-0.005 cm gusseted bags.
(2) Filling material: this refers to promptly filling the prepared culture material into the spawn bags. Each bag is filled with 0.4-0.6 kg of wet material, and after compaction the material height is 10-12 cm. If, after filling is completed, a wooden stick with a diameter of 1-1.5 cm, thick at the top and pointed at the bottom, is used to make a hole 6-8 cm deep in the middle of the material, it helps speed up spawn running and facilitates inoculation.
3. Sterilization
Cultivation spawn often uses two methods: high-pressure sterilization and normal-pressure sterilization. For high-pressure steam sterilization, keep it for 1.5-2 hours when the steam pressure in the pot reaches 0.15 MPa and the material temperature is 126°C; for normal-pressure steam sterilization, it should be kept for 10-12 hours when the material temperature reaches 98-100°C.
4. Inoculation
This is generally carried out in an inoculation box and inoculation room. Use an ozone atom sterilizer for half an hour of sterilization, use 75% alcohol for surface disinfection, then according to aseptic operating procedures transfer the stock spawn into the material bags and plug the cotton plugs. Generally, each bottle of stock spawn can inoculate 40-50 bags of cultivation spawn.
5. Spawn culture management
Cultivation spawn culture is generally carried out in a culture room. The spawn culture room is required to be clean and dry, with good ventilation and temperature control conditions. During the entire management period, the main management work includes temperature regulation, humidity adjustment, ventilation, checking spawn running and promptly removing contamination.
(1) Temperature adjustment: when adjusting temperature, pay attention to the difference between material temperature and room temperature. Mycelium generates heat during growth, and the material temperature is often higher than the room temperature. As the culture time lengthens, the gap between material temperature and room temperature also increases. According to this principle, the temperature of the culture room should be relatively high in the initial stage, preferably controlled at 24-26°C. After 15 days of inoculation, the room temperature should preferably be controlled at 20-22°C.
(2) Humidity adjustment: the relative air humidity of the culture room is preferably controlled at 60-70%. If humidity is too high, the spawn is easily contaminated by miscellaneous bacteria; if humidity is too low, the surface culture material of the stock spawn easily loses water, causing difficulty in colonizing the material or slow spawn running.
(3) Ventilation: ventilation helps reduce the carbon dioxide concentration in the culture room, increase oxygen, and regulate the culture room temperature. When the temperature is high, ventilation should be carried out from evening to early morning; when the temperature is low, it should be carried out at noon when the temperature is high.
(4) Avoiding light: shiitake mushroom mycelium does not require light for growth. Under dark conditions, the mycelium grows vigorously and is thick and white, while strong light instead inhibits mycelial growth. Therefore, spawn culture should be carried out under light-avoiding conditions, especially avoiding strong light.
(5) Observation of spawn running and inspection for miscellaneous bacteria: during the culture process, inspections for miscellaneous bacteria contamination and spawn running should be carried out frequently. To ensure the purity of cultivation spawn, the period from 7 days after inoculation until the mycelium covers the surface of the culture material is the key period for inspecting miscellaneous bacteria. Once miscellaneous bacteria are found, they should be removed promptly. Spawn running inspection should be carried out at any time throughout the entire culture period, and when abnormal mycelial growth is found, the cause should be investigated promptly.
Under suitable culture conditions, after 35-40 days of culture, the mycelium can cover the entire bag, and the cultivation spawn can be used for production. If the spawn that has already been cultivated cannot be used for production for the time being, it should promptly be stored in a cool, dry, ventilated and light-avoiding place. If conditions permit, moving it to low-temperature cold storage is even better.
(II) Operating procedures for producing mushroom sticks
1. Material mixing formula: sawdust 95%, wheat bran 4%, gypsum powder 1%. First sieve the sawdust well, sprinkle on the wheat bran and gypsum powder, mix for a while in a mixer, then mix in water. Material-to-water ratio 1:1-1.2, water content 58-60%, pH 6-6.5.
2. Bagging: use a bagging machine with a group of 5-8 people, one person filling material, one person making bags, one person bagging, and the rest sealing the openings. The material should be filled with moderate tightness, and the bag opening must be tied tightly with tear film.
3. Sterilization: place the material sticks into a normal-pressure sterilization pot for sterilization. When arranging the material sticks, the upper and lower bags should form straight lines, and space should be left in the middle of the front and back stacks so that airflow can pass smoothly from bottom to top and avoid "dead corners." Ignite the fire promptly to raise the temperature so that it rises to 100°C in the steaming pot as quickly as possible within 5 hours, and keep it at constant temperature for 18 hours.
4. Inoculation: after sterilization, take the material sticks out of the pot and stack them in a "well" shape to cool. Inoculation is done with a group of 7 people. First sterilize the cooled material sticks with an oxygen atom sterilizer for 1 hour. In the inoculation tent, in front of the sterilizer, one person makes holes, three people place spawn, two people put on bags, and one person ties the openings.
5. Culturing: stack the inoculated mushroom sticks in a "well" shape, with a stack height of 13 layers, and culture at a constant temperature of 24+2°C or 24-2°C. When the spawn ring grows to 6-8 cm, begin removing the bags; when the spawn ring is above 8 cm, begin "small air" release, piercing 8-10 holes in the mushroom sticks with toothpicks; when the mycelium covers the entire stick, release "large air" in the early stage of color turning, piercing about 120 holes on all four sides. Entering the color-turning period, the piles must be turned several times until all have turned color; in the early fruiting stage, pierce the overly heavy mushroom sticks with holes again, so that the water inside the mushroom sticks evaporates to reach the water content for the fruiting stage.