Detailed Explanation of Key Points for Pollution-Free Shiitake Mushroom Cultivation Techniques

Fungal mushrooms include straw mushrooms, shaggy mane mushrooms, shiitake mushrooms, oyster mushrooms, etc. Shiitake mushrooms are deeply loved by consumers for their delicious flavor, and due to their @#@136@#@ relatively high price, along with cultivation and management techniques that are easy to learn and understand, they are very suitable for farmers to cultivate during the leisure autumn and winter seasons.

1. Mushroom Bag Preparation

1. Raw Material Preparation: Mulberry branches, apple branches, or other broadleaf trees such as poplar, willow, paulownia, and locust can all be used as cultivation substrate, as long as they are not moldy, they can be used after crushing.

2. Selection of Cultivation Period: The optimal season is from late August to mid-September. The ten-day highest temperature is below 30°C, and the ten-day average temperature is 26-28°C.

3. Temperature requirements for shiitake mushroom bag mycelium incubation: From 1 to 7 days after inoculation, the bag temperature is 1-3°C lower than room temperature, and room temperature can be controlled at 28-30°C; from 7 to 10 days, the required incubation temperature is 26-28°C. From 10 to 15 days, the bags begin to self-heat, and the required incubation temperature is 24°C-28°C. After 15 days, the self-heating of the bags and the natural temperature decline are basically synchronized. If managed properly, with reasonable use of ventilation, placing bags densely or sparsely, and increasing or decreasing the number of layers, the entire incubation period of 60-70 days (such as planting in mid-August to mid-September) can be completed smoothly basically without heating equipment, relying on natural temperature, meeting the requirement of basically constant-temperature mycelium cultivation. This can reduce a lot of manpower and material resources, lower costs, and also achieve good mycelium incubation, timely mushroom production, high yield, good quality, and high economic benefits.

Shiitake mushrooms require constant-temperature mycelium incubation and variable-temperature fruiting. If in the middle to late stage of incubation, artificial heating must be used to meet the requirement of constant-temperature incubation. In the vast rural areas with relatively poor infrastructure conditions, sometimes the temperature difference is above 5-10°C, which greatly affects mycelium growth and development and physiological maturation, delays the fruiting period, and results in low yield, quality, and economic benefits.

4. Grasp the "Three Critical Points" for High Yield: (1) The ten-day average temperature during the inoculation period should not exceed 28°C. (2) During bag removal and color conversion (about 60 days of cultivation), the ten-day average temperature should not be lower than 15°C. (3) During the fruiting period, that is, when the first batch of fruiting bodies forms and grows to over 1cm, the first flush of mushrooms must be harvested before the first cold wave arrives locally. For bag-cultivated shiitake mushrooms in the vast rural areas, these three critical moments must be firmly grasped; otherwise, management will be difficult, costs will increase, the period for producing high-quality mushrooms will be short, mushroom quality will be poor, and economic benefits will be low.

Years of practice have proven that the latest cultivation period is the end of September; for every 10 days of delay, the fruiting period will be delayed by one month, and generally economic benefits will be reduced by one-quarter to one-third. Therefore, the "Three Critical Points" must be grasped.

5. Ingredients: (1) Sawdust 38.5kg, wheat bran 10kg, gypsum 1kg, sugar 0.5kg, pH 7.0-7.5, moisture content 55-60%. (2) Sawdust 35kg, cottonseed hulls 7kg, wheat bran 6.5kg, gypsum 1kg, sugar 0.5kg, pH 7.0-7.5, moisture content 55-60%. The above raw materials must be weighed accurately and stirred repeatedly and evenly. "If the substrate and water are not mixed evenly, mushroom cultivation will be a disaster." Appropriately raising the pH value helps prevent contamination by competitor fungi, improves the pure culture rate, promotes early decomposition and utilization of lignin by mycelium, and advances fruiting. Ingredient requirements: reasonable ratio, accurate weighing, even mixing, slightly dry rather than wet.

6. Bag Filling: Use specialized cylindrical bags for edible fungi, requiring uniform thickness, tensile strength, temperature resistance, able to withstand temperatures of 115°C, and free of micropores, high-quality plastic bags. Cut into lengths of 60-65cm, tie one end with evenly made small folds using string, then burn and melt with a candle flame, ensuring absolutely no air leakage. Put the evenly mixed cultivation substrate into the bag, with appropriate tightness, not too compact or too loose, so that when holding the center of the filled bag with the hand, there is no soft feeling, and the two ends of the bag do not droop. When tying the bag opening, wipe clean the cultivation substrate adhering to the bag opening before tying, to prevent contamination by competitor fungi from this point. Filled bags should be handled gently and not placed directly on the ground; spread burlap sacks, woven bags, or similar materials underneath to prevent sand particles from piercing the bags, causing micropores that lead to competitor fungus infection and water bags.

7. Steaming: Fill the steamer with enough water, arrange the tied bags with tops and bottoms aligned, loading them in batches up to the top of the steamer; do not arrange the bags in a "#" shape. Start the fire before loading the steamer, or start the fire simultaneously with loading. Use a large fire to try to reach 100°C within 4-6 hours; after reaching 100°C, do not lose water or let the temperature drop, consuming about 20kg of water per hour, maintaining for 20 hours (or longer) to achieve sterilization effect.

8. Inoculation: The inoculation room and incubation room are in the same room. Clean thoroughly 7-10 days before use. For old rooms, brush the walls with lime water; if the room is damp, sprinkle quicklime to remove moisture. Four days before use, place the tools used for taking bags out of the steamer into the room, seal doors and windows to achieve airtightness. Use 0.5-1kg of sulfur per room, ignite and fumigate the room, keeping the door sealed until opening when materials are brought in. Begin inoculation when the bag temperature drops to 30°C. The best time for inoculation is in the evening and early morning. Before inoculation, spread 5-10cm thick lime at the doorway; entering personnel must step over the lime, called "white lime sealing the door." Inoculation personnel should maintain good personal hygiene, be skilled, fast, agile, and well-coordinated. Four people form a team: one wipes the bag surface and makes holes, one applies the spawn, one applies adhesive tape, and one transports. Before inoculation, light the alcohol lamp first; all tools used for inoculation must be flame-sterilized. Use an inoculator to remove spawn in whole blocks, quickly insert into the holes, trying not to break the spawn apart. After each bag is inoculated, the inoculator must be flame-sterilized over the alcohol lamp before inoculating the next bag, to prevent cross-contamination due to spawn issues.

2. Cultivation

1. Mycelium Incubation: Bag mycelium incubation and cultivation is a serious, meticulous, and relatively long complex task. The entire process from inoculation to physiological maturation of the bags takes about 60 days. Because shiitake mushrooms are fungi that require constant-temperature mycelium incubation and variable-temperature fruiting, the entire incubation period requires basically constant temperature of 24±2°C, relative humidity below 70%, dim light, and ventilation. The incubation temperature must be constant at 22-26°C (substrate temperature), absolutely not too high or too low. The effective accumulated temperature must reach above 1200°C for fruiting. In the early stage, mycelium growth and development is best at 24°C; in the later stage, extracellular enzyme secretion is most vigorous at 27-28°C, with the strongest ability to decompose lignin, cellulose, and hemicellulose, accumulating large amounts of nutrients, which is beneficial for fruiting.

Shiitake mycelium is sensitive to temperature stimulation. The specific measures and operating methods for bag cultivation after inoculation are as follows: 1-6 days: Do not turn or move the bags, do not ventilate. At this time, the bag temperature is 1-3°C lower than room temperature, and room temperature can be controlled at 28-30°C, which is exactly suitable for mycelium incubation temperature needs. After inoculation, measure temperature 3-4 times daily, shade doors and windows to create dim light indoors, continuing until about 50 days. 7-10 days: Mycelium has colonized the substrate and begun to grow. On the 7th day, perform the first turning of the pile, checking bag incubation and competitor fungus infection; handle any competitor fungi immediately and replenish any missed inoculation spots in time. Thereafter, turn the pile once every 7-10 days. For the first two turnings, handle gently; for subsequent turnings, the technique can be firmer to enhance stimulation. Ventilate 2-3 times daily for 30 minutes each time. 11-15 days: Mycelium has begun vigorous growth. For mycelium growth, focus on heat preservation while increasing ventilation, and perform the second turning of the pile. 16-20 days: Mycelium proliferates in large amounts; room temperature can be controlled at 22-24°C, focus on heat preservation with appropriate ventilation. After 21 days: Mycelium at inoculation holes connects. With hole opening and piercing for oxygen supplementation, the bag self-heating can be 5-10°C higher than room temperature. Pay attention to ventilation, disperse the pile to cool down.

After the mycelium at the hole openings has interconnected, the main task is to reasonably and scientifically use pile turning and ventilation to regulate temperature, meeting the temperature requirements for mycelium development until basically constant temperature is achieved. This work is maintained until the end of bag cultivation at about 60-70 days. 50-65 days: Verrucose formations appear on the bag surface, and brown pigment secretion increases. After 50 days, remove the shading from doors and windows, provide light stimulation to promote physiological maturation of the bags. Before bag removal, raise the bag temperature to 27-28°C and maintain for 4 days, allowing mycelium to decompose and accumulate large amounts of nutrients, preparing for good fruiting. After bag cultivation maturation, when the ten-day average natural temperature is below 14°C, color conversion cannot proceed smoothly after bag removal, affecting future fruiting. Therefore, perform color conversion while still in the bags; when the entire bag has converted color to one-third, the bags can be removed for fruiting.

2. Bag Removal Methods and Precautions: (1) Transport the bags to the mushroom shed or a specially designated facility. (2) Use a sharp knife to cut open the plastic film; wipe the blade and cutting area clean with alcohol cotton balls for disinfection. The cut should not be too deep; just enough to cut through the film without damaging the mycelium. (3) Perform bag removal inside the mushroom shed. If using a specially designated color conversion site, remove bags, place them, and cover with film simultaneously to prevent dehydration and drying of the bags and mycelial film. (4) Best to perform bag removal on cloudy days or in the early morning or evening of sunny days; not suitable on windy days. (5) Bags infected with competitor fungi should not have their bags removed; adopt the method of fruiting with bags on. (6) Beforehand, spray the designated color conversion site or mushroom shed with a sprayer to moisten, maintaining spatial relative humidity at 85%.

3. Color Conversion Management: Color conversion is a unique characteristic of shiitake mushrooms; it is the sign and physiological process of transition from vegetative growth to reproductive growth, and further to weight maturation and fruiting body formation. The bag surface first grows a layer of white cottony aerial mycelium, which then falls flat, forming a thin mycelial film, while beginning to secrete pigment and exude yellow water. The bag turns from white to pink, then brown-purple, with a metallic luster; the mycelial film called "artificial bark" is known as color conversion. The specific management measures are: (1) 1-4 days after bag removal, seal with film, do not turn the bags, maintain temperature at 18-22°C, humidity at 85%, and shade to create darkness. (2) Days 5-8: The mycelium surface secretes a layer of yellow to brown water droplets. At this time, combine with film uncovering and ventilation, spray water on the bags for two consecutive days. On the first day, use a sprayer to spray lightly, dispersing the yellow-red water droplets; on the second day, spray with pressure to wash away the overly concentrated brown-red water droplets. Then, when the mycelium on the bag surface is dry and not sticky to the touch, re-cover with film. Color conversion generally completes in 8-12 days. (3) Days 9-15: After color conversion is complete, perform daily wet-dry difference and temperature difference stimulation, widening the day-night temperature difference to above 10°C, but ensure the minimum is 8°C and maximum is 22°C for 3-4 consecutive days, and a large number of mushroom buds will appear.

4. Variable-Temperature Bud Induction: Shiitake mushrooms belong to the low-temperature, variable-temperature fruiting type of fungi. When the mycelium transitions from vegetative growth to reproductive growth, under conditions of relatively low temperature and large day-night temperature difference, mycelium growth slows down, prompting nutrients and water to accumulate into aggregation points, thereby forming primordia. Primordium formation requires creating a temperature difference and wet-dry difference condition to ensure primordium formation and normal development into mushroom buds. Specific measures are as follows: Widen the temperature difference in the mushroom shed, use low-temperature variable-temperature bud induction. When the ten-day average temperature is 8-22°C, it is suitable for bud induction. But the temperature difference must be widened to above 10°C, with a wet-dry difference of 15%, and after 3-4 consecutive days of treatment, the mycelium can interweave into primordia. For bags that have already produced one or two flushes of shiitake mushrooms, timely replenish the water content inside the bags.

3. Harvesting and Standards of Shiitake Mushrooms

After the bags have completed color conversion and entered normal fruiting management, when the shiitake mushroom cap diameter grows to 4-6cm without the veil opening, it is the optimal harvest standard. At this time, the quality of shiitake mushrooms is the best and the commercial value is the highest. When harvesting shiitake mushrooms, be sure to remove the base of the mushroom from the bag to prevent mold infection of the bag.