Detailed Explanation of Key Points for Lightweight Cultivation Technology of Substitute-material Shiitake Mushrooms
Since the 1990s, the substitute-material flower shiitake cultivation technology successfully researched by the Qingyuan County Edible Fungi Research Center has been rapidly promoted and applied nationwide, making major contributions to poverty alleviation and prosperity in rural areas and to the transformation of shiitake production from quantity-oriented to quality-oriented. However, in substitute-material shiitake production, processes such as substrate log sterilization, inoculation operations, and manual bag cutting require large labor inputs, and problems such as low substrate log success rates, uneven fruiting, and deformed fruiting bodies have long constrained the development of shiitake production, especially creating major obstacles for intensive production. For this reason, our center conducted years of research on labor-saving, low-consumption, high-yield, and high-quality cultivation technology for substitute-material shiitake, completed four key technical improvements, and summarized and formed a set of lightweight cultivation technology for substitute-material shiitake. The technical improvements are described below.
1 Semi-raw material sterilization technology
Substitute-material shiitake logs must first undergo heating sterilization before inoculation. The sterilization temperature is required to reach 98-100°C and be maintained for more than 12h. Conventional sterilization requires continuous operation for 30-40h, causing high labor intensity for mushroom farmers. Even so, due to uneven temperature inside the sterilization stove, incomplete sterilization still often occurs, affecting the economic benefits of shiitake cultivation. Semi-raw material sterilization technology uses the non-toxic sterilizing agent "Kemeiwang", organically combining physical sterilization and chemical sterilization, and can achieve thorough sterilization in the medium temperature range of 60-80°C. Both sterilization energy consumption and sterilization time are reduced by more than 50%, and the mycelium growth speed, mycelial competitive ability, and survival rate are all greatly improved. Its application effect is very significant, and it has now been promoted and applied over large areas nationwide.
To produce 1000 shiitake logs (15cm x 55cm bags), that is, 0.85t of dry culture material, add 4kg of the new generation "Kemeiwang" powder. First evenly dissolve the "Kemeiwang" powder in water to prepare a medicinal solution, then add the solution to the culture material and repeatedly stir thoroughly to make it uniform. A dry-mixing method may also be used: first add the "Kemeiwang" powder together with gypsum directly to wheat bran and mix well, then mix the bran containing the agent with sawdust, and finally add water and repeatedly mix thoroughly. However, with this dry-mixing method, clumped powder must be completely crushed before use. The culture material must be mixed evenly; making all culture material contain the same concentration of the agent is the key to this process. If the culture material contains cottonseed hulls, the cottonseed hulls should first be pre-soaked with the prepared medicinal solution, then mixed with the other culture materials. After the culture material is mixed evenly, it should be bagged promptly and heated for sterilization; bagging follows conventional operations. Temperature control for semi-raw material sterilization: when the material temperature in the lowest-temperature zone inside the stove reaches above 80°C, maintain the fire steadily and hold for 4-6h, then stop the fire, use the residual heat inside the stove to sweat-stack for more than 12h, and then remove from the stove.
Advantages of semi-raw material sterilization technology: (1) It avoids the most difficult heating process between 80-100°C, saving labor, time, and fuel: compared with the conventional method, sterilization time is shortened by half and fuel is saved by more than 50%. (2) Improved survival rate: the finished product rate of substrate bags can stably reach 95%-100%. (3) Good fruiting performance: test and production application results show that it is basically equal to or slightly higher than the conventional method, while individual mushroom weight is significantly increased.
2 Application technology of shiitake capsule spawn
Shiitake capsule spawn is a new type of spawn suitable for inoculating substitute-material substrate logs, developed through further innovation based on advanced log inoculation technology from Japan and South Korea and combined with China's actual production conditions. Each sheet contains 600 conical spawn pellets. The design is scientific and the standard is standardized, making transportation, storage, and inoculation all very convenient. In particular, the spawn has a fixed shape, making spawn removal extremely convenient, with short air exposure time and few contamination opportunities; during inoculation operations, the mycelium is not damaged, can directly feed on the substrate, and preferentially occupies the medium; it comes with a sealed breathable cover, which can both prevent contamination by foreign microorganisms and maintain moisture in the spawn block, promoting mycelial growth. The finished product rate can generally be increased by 5%-10% compared with traditional spawn, inoculation is rapid, work efficiency is increased by 1-2 times, and raw material consumption for spawn production is reduced by more than 80%. The quality and yield of the shiitake produced are no different from those with traditional spawn.
Operational requirements: (1) Bagging must be tight and solid. (2) During the cooling process, prevent dust contamination on the surface of the substrate logs. (3) Cooling and inoculation can be carried out in the same room, which must be clean and dust-free with no air movement. (4) Before inoculation, carry out aerosol disinfection of the substrate logs; during disinfection, do not place the spawn into the disinfection space. (5) Before inoculation, the operator's hands, the spawn honeycomb tray, and the specially made punching rod used for inoculation must all be wiped and disinfected with "Jiezhongling" or 70%-75% medicinal alcohol. (6) After punching, insert the spawn immediately; the exposure time of the spawn and holes in the air should be as short as possible. The punching rod should not leave the hand and must not be placed anywhere. (7) When removing spawn, gently press the breathable cover of the spawn with the right index finger, support from the bottom upward with the left index finger, then gently pinch the spawn cover with the right thumb and index finger to take out the spawn, quickly insert it into the inoculation hole of the substrate log, and lightly press the cover so that it seals with the surface of the bag. Be careful not to touch the spawn part below the cover with your hands. (8) After inoculation is completed, put the outer bag back on; the bag opening does not need to be tied tightly. (9) After mycelium growth of 6-8cm, perform the first piercing for aeration. Because capsule spawn is more sealed than conventional spawn, this should be done more promptly than with conventional spawn, and the number of piercings should be appropriately increased.
3 Open inoculation technology
Conventional shiitake inoculation mainly uses an inoculation box, which is slow, labor-intensive and time-consuming, and has a low survival rate. Our center summarized the valuable experience of mushroom farmers and, through careful research, introduced open inoculation technology.
Key operational points: (1) Before the substrate logs are removed from the stove, clean in advance the site where the substrate logs will be stacked, reducing contamination sources as much as possible. (2) After the substrate logs are sterilized and removed from the stove, place them tightly horizontally and stack them into a wall style; the wall-style stack height should not exceed 1.2m, and the length and distance between walls depend on the stacking site. Promptly cover the stack with plastic film to prevent dust and spores from falling. (3) Before inoculation, first disinfect the substrate logs with an aerosol disinfectant; for 1000 shiitake logs (15cm x 55cm bags), use 4 boxes (each box 40g) of disinfectant, with disinfection time not less than 2h. (4) During inoculation, one person pulls the substrate logs out from the plastic film and brushes on Jiezhongling, one person punches holes, and one person places spawn. (5) During inoculation, use cotton to apply "Jiezhongling" solution to the part to be inoculated, with a brushed width of about 5cm, then punch and inoculate before the solution dries; do not apply too much solution, and avoid solution flowing into the inoculation holes. (6) After inoculation, the other operating procedures are the same as conventional ones.
Open inoculation with capsule spawn: simply wipe and disinfect the spawn hole tray, inoculation tools, and the hands of inoculation personnel with Jiezhongling, and also wipe the inoculation parts of the substrate logs. In a relatively clean environment, aerosol disinfection can even be omitted and fully open inoculation can be carried out directly.
4 Fruiting technology of flower shiitake without cutting bags
In flower shiitake cultivation, manual bag cutting is the most cumbersome process, consuming large amounts of labor and very easily causing deformed fruiting bodies. Substrate log water-retention technology avoids this cumbersome manual bag-cutting process. After removing the bag from the substrate log, a water-retaining agent is brushed on, forming a water-retaining film layer, and flower shiitake grow naturally. It has the characteristics of saving labor and effort, good mushroom shape, excellent mushroom quality, high flower shiitake rate, maintaining moisture, convenient operation, and no toxic side effects on the human body or mushroom bodies. The key points of the fruiting technology of flower shiitake without cutting bags are introduced below:
4.1 Substrate log selection (1) Select main flower shiitake cultivars such as Qingyuan 9015, Qingke 20, 939, and 135; (2) select substrate logs free of foreign microorganisms and rot, with normal color change and physiologically mature mycelium; (3) the substrate logs should have moderate water content; lighter substrate logs should first be replenished with water before brushing on the water-retaining agent.
4.2 Brushing time Within 1 week before the first or second flush of fruiting, when mushroom buds have not yet emerged (choose a weather period with relatively low temperature and slightly higher humidity). If a small number of mushroom buds have already appeared, remove them before brushing; never brush the water-retaining agent directly onto the mushroom buds.
4.3 Brushing method Flower shiitake water-retaining agents come in solid or liquid products. Solid water-retaining agent should be heated until completely melted before use; liquid water-retaining agent should be stirred evenly with a wooden stick and used directly. When using, remove the bag from the substrate log, and either soak for 0.5s or evenly apply it to the substrate log with a paint brush.
4.4 Fruiting management For substrate logs using water-retaining agent, the management links of "increasing humidity to induce buds and fruiting" and "moisture retention, resting, and mycelium recovery" must be well handled. After brushing on the water-retaining agent, avoiding hardening of the mushroom skin is key. Except that after mushroom buds grow to 2cm ventilation needs to be strengthened to induce flowering, at other times ventilation must not be excessive. (1) Increasing humidity to induce buds and fruiting: frequently close the greenhouse film or cover the substrate logs with film so that the surface of the substrate logs does not dry out, which is favorable for mushroom buds to emerge. When the air in the shed is dry and relative humidity is low, spray clean water on the substrate logs to keep the water content of the substrate logs moderate and maintain relative humidity in the mushroom shed at 85%. (2) Moisture retention, resting, and mycelium recovery: during the interval between flushes (during the mycelium recovery period), cover with film to retain moisture; after 8d, increase humidity to induce buds and fruiting; when substrate logs are lighter, replenish water promptly. (3) After mushroom buds grow to more than 2cm, uncover the film for ventilation management to form flower shiitake.