Analysis of Off-Season Shiitake Mushroom Production and Market Conditions

Off-season shiitake mushrooms are produced during the high-temperature season from May to October using natural conditions such as mountain caves and civil air defense structures, or facilities such as constant-temperature cold storage. Nowadays, off-season cultivation is mostly carried out in existing cold storage (constant-temperature warehouses) or ordinary greenhouses using cooling equipment. The technical key points are:

1. Facility preparation: For an ordinary edible mushroom greenhouse, after completing spring production, immediately clean up, remove the original mushroom bags, clean the interior of the greenhouse, check and repair the greenhouse film, spray an appropriate amount of medication for sterilization, then build fruiting racks at a tier height of about 25-35 cm, with each rack having about 5-7 tiers, and connect and secure the tops of the racks with thin bamboo poles or similar. After confirming everything is correct, fill the greenhouse with clean water, wait for the water to seep down, then spread lime powder inside the greenhouse, and the mushroom bags can be moved onto the racks. The shelving setup and disinfection and sterilization in cold storage can be done with reference to the above.

2. Lowering the temperature: At present, a "multi-functional water-temperature air conditioner" can be used for production. This equipment can both provide cooling for production in summer and heating for cultivation in winter, serving two purposes with one machine, with obvious energy savings and excellent results. In 2004, a demonstration application was carried out at our unit's edible mushroom base. During the spawn running process in July and August, it could reduce the culture temperature to 20-25°C, with very good results. One unit is sufficient for every 150-200 sq m of greenhouse. In cold storage, the temperature can be regulated at 15-25°C according to the different growth stages of shiitake mushrooms, and when necessary, such as during the pinning induction stage, it can be lowered to about 8°C.

3. Color-turning management: Carry out spawn production and mushroom bag production according to conventional production procedures. After all spawn running is completed, stack the white mushroom bags in a "#" pattern to a height, and cover them with plastic film, straw mats, etc., so that while raising the temperature, by adjusting the covering of straw mats and plastic film as well as uncovering and covering at night, first, the white mycelium on the surface of the bags is induced to lie down, and second, the temperature difference of the bags is increased to promote color turning as quickly as possible. At this stage, if conditions permit, the temperature difference should be widened as much as possible to above 20°C to accelerate and promote uniform color turning.

4. Temperature regulation to induce pinning: After color turning is completed, the mushroom bags, after water replenishment treatment, can be moved into the greenhouse and arranged in a single layer at intervals of about 5 cm, with cooling treatment carried out through the "multi-functional water-temperature air conditioner." After 1-2 days, high-temperature stimulation is then applied. Together with stimulation from water and light in the greenhouse, small mushroom pins appear in about one week. After that, maintain conventional water management and minimize humidity differences as much as possible to ensure a continuous emergence of pins. The basic management indicators at this stage are: temperature maintained between 20-30°C, with a temperature difference of about 10-15°C; air humidity between 75-95%. Because shiitake mushroom caps are relatively thick and can adapt to relatively large humidity differences, there is no need to worry that too large a humidity difference will cause death. By adjusting the covering on the greenhouse roof, keep the light intensity inside the greenhouse at 300-1200 lux. Provide appropriate ventilation to keep the air inside the greenhouse relatively fresh.

5. Fruiting management: Because the plastic film of shiitake mushroom bags is relatively thick, the pins cannot break through the bags on their own, so the plastic film must be cut open manually. The method is: at the place where pins appear, use a small blade to cut open the plastic film, being careful not to damage the pins. If management is careful, the plastic film can be cut in a circular opening around the pin, which can avoid deformed mushrooms to the greatest extent. From the time the young pins extend out, the fruiting management stage begins. At this stage, maintain: temperature at 20-28°C, humidity between 75-95%, light of about 500-1000 lux, and appropriate ventilation. When the cap diameter reaches more than 2 cm, the three-dimensional edible mushroom nutritional essence can be sprayed directly on the fruiting bodies. When the edge of the shiitake cap is still curled downward (gong-edge) but shows a tendency to expand, it should be harvested in time. Note that, to a certain extent, the greenhouse temperature and "foliar fertilization" at this stage will determine the quality of the shiitake mushrooms.

6. Management after each flush: The flushes of shiitake mushrooms are relatively obvious. After one flush is harvested, the mushroom bags lose water relatively seriously, so water replenishment and spawn restoration are needed before managing and harvesting the next flush. The common method of water replenishment is: use the original ditches, canals, pits, or dig an earthen pit, line it with plastic film, arrange the mushroom bags inside, and when about 20 cm from the upper edge, lay a plastic film to form a concave shape, fill the concave shape with water, and after a certain pressure is formed, pour water into the pit containing the mushroom bags. After filling, maintain for 24 hours, then drain the water, place the mushroom bags back on the fruiting racks, and manage with reference to the above. Generally, 4-5 flushes can be harvested, with biological efficiency around 80%, and higher yields can exceed 110%.

2. Problems are inevitably encountered in any production, and the same is true for off-season shiitake mushrooms. During growth management, prevention should be the main approach. Once a problem occurs, it should be handled promptly to provide the greatest guarantee for high-yield, high-quality production:

-- Small and thin caps: This appears as caps that are both thin and small. Even if the mushrooms are older, they cannot grow larger, and when eaten fresh they lack the special aroma of shiitake mushrooms. Control measures: For mushroom bags that have not turned color, conditions must be regulated to carry out color turning. If the substrate nutrients are insufficient, the three-dimensional nutritional essence can be supplemented when soaking the mushroom bags. The method of "foliar fertilization" can also be adopted. For example, spraying three-dimensional nutritional essence can effectively increase cap thickness. Summer temperatures are relatively high, so effective cooling measures should be taken. If a "water-cooled air conditioner" is used, there is no such concern.

-- Lampshade-shaped caps: The caps take on a pointed lampshade shape and are obviously thin, seriously reducing commercial quality. The main cause is the same as above, so control can refer to the above.

-- Wavy caps: The cap edges show a relatively regular wavy shape and are also obviously relatively thin and brittle. The control measure is that after pins appear, relatively mild temperature and humidity should be maintained. Especially in off-season cultivation in summer, the greenhouse temperature is often the basic condition determining whether the fruiting bodies can develop normally.

-- Irregular caps: The specific manifestation is that the caps are crooked and twisted, or elongated, or triangular, and so on. In short, not being round and regular is their main feature. Control measures: Cut the film in time and carry out pin thinning. Generally, only select 1-2 young pins, not too many.

-- Hollow stipes: The stipes are slender and hollow, causing the caps to also be very small. Control measures: After each harvest, soak the bags. Generally, soaking for 24 hours can restore them to their original weight. Keep the air humidity in the mushroom greenhouse above 85%.

-- Stipes growing out from cracks: When the water content of the mushroom bags is too low, the substrate cracks. After narrow and long cracks form, fruiting bodies can grow out from the cracks. Some do not even fully emerge, and the caps grow larger inside the cracks, ultimately failing to achieve their commercial value. The control measure is to persist in soaking the mushroom bags after each flush is harvested so that cracks do not form.

-- Twisted stipes: This phenomenon is likely to occur when the air humidity in the mushroom greenhouse is relatively low, the light is relatively strong, or the light angle changes too frequently. As long as relatively stable air humidity is maintained and relatively stable lighting is maintained, generally about 1000 lux of scattered light is sufficient.

-- Candle mushrooms: The feature of candle mushrooms is bare stipes with no normal cap tissue, shaped like candles. Control measures: Cut the film in time. When thinning pins, be careful not to damage the pins intended to be retained. Persist in good ventilation and maintain relatively fresh air conditions inside the greenhouse.

3. Last year's shiitake mushroom market was generally strong in both production and sales. Dry product prices jumped upward from November. By January of this year, prices had risen sharply by 150% compared with October. The highest selling price of off-season products (supermarkets) reached 18 yuan (per kg, the same below). Wholesale prices in farmers' markets remained at 6-8 yuan, and market retail prices remained between 8-12 yuan. The lowest point was in May, when it once dropped to around 5 yuan, but it was maintained for only a short time. Based on information feedback and comprehensive analysis of production habits in various places and the technical levels of mushroom farmers, the production quantity of off-season shiitake mushrooms this year will increase by a certain margin compared with last year, but due to constraints such as technology, investment, and raw materials, the increase will not be very large and should generally be around 20%. It is expected that entering June, the @#@136@#@ price of off-season fresh shiitake mushrooms will remain at around 7 yuan. After mid-July and into August, it can reach 8-10 yuan. The price of fresh shiitake mushrooms in supermarkets can remain above 12 yuan and show a firm or increasing trend. Such a high price level first shows that consumers have already recognized and understood shiitake mushrooms. Second, it also shows that our production quantity is still on the low side. Third, as people's income levels rise, it is also reasonable for shiitake mushrooms, known in foreign markets as "anti-cancer food," to rise substantially in price on the market.