What are the control measures for the difficulty of shiitake mushrooms fruiting in bag substrate
In recent years, the "Xixia model" of cultivating flower shiitake mushrooms on plastic racks with bag substrate as the main body has become a model for the south-to-north migration of mushrooms in China, blooming all over the country. However, due to regional climate temperature differences and the fact that mushroom farmers in newly developed areas have little understanding of shiitake mushroom variety types and fruiting characteristics, they used medium-temperature shiitake varieties such as 135, 241, 939, L26, etc., or similar strains, and when forcing fruiting in low-temperature seasons, the abnormal phenomenon of being unable to fruit normally after forcing occurs, resulting in reduced yield in mild cases and loss of capital in severe cases. Now we present our management measures for controlling the difficulty of shiitake mushrooms fruiting in bag substrate as follows.
1. Choose suitable strains. If the winter temperature is mainly around 15°C, choose low-temperature strains that fruit at 5-18°C, such as 193, 135, 7410 (Rinong Large Leaf), and strains with a wide fruiting temperature range of 8-22°C, such as 925, 938, Zhongxing No. 8, etc. If there is no choice, and medium-temperature strains have been used, the following measures can be adopted to achieve smooth fruiting.
2. Control moisture when mixing substrate. The water content of the culture substrate in the bags is 50%-55%. That is, the ratio of dry raw material to water is 1:0.8-0.9, and for fresh wood chips, add water at 1:0.5-0.7. The substrate-to-water ratio of 1:1.2 commonly introduced in materials results in a culture substrate water content exceeding 55%.
The formula for calculating the water content of the culture substrate is: culture substrate + water = total culture substrate, the water content of the culture substrate itself (generally after sun-drying, the water content of the substrate is about 3-18%) + water = total water, total water ÷ total culture substrate = water content %. For example, adding 90 kg of water to 100 kg of raw material with a water content of 15%, substituting into the above formula, gives a water content of 55.26%. When the water content is below 45%, the mycelium grows thin and slow; when the water content is above 65%, the mycelium growth stagnates.
3. Dehydration and color change. After the bags are fully colonized by mycelium, move them into the fruiting shed, and use a screwdriver with a diameter of 5-8 mm to pierce 4 rows of holes in the bags, 10-15 holes per row, with the hole depth being half the diameter of the bag. This prompts the mycelium to differentiate the culture substrate, allows the accumulated water to evaporate appropriately, and provides "porous" conditions for the yellow-brown liquid secreted during the color change process of the bags to flow out automatically, preventing the colored skin from becoming too thick or the bags from being damaged by accumulated water. Among them, summering bags can change color at natural temperature; for summer-autumn cultivation bags, the color change management temperature is 15-26°C, with the optimum being 18-22°C. During the color change stage, rotate the bags once every 6-10 days to prompt the accumulated water inside the bags to flow out.
4. Ventilation for summering. Leave about 1 m of ventilation channel between the sun-blocking fences around the summering shed and the opposite edge of the shed. Every day, open the ventilation openings wide on the side of the shed facing away from the sun: the northwest side in the morning and the southeast side in the afternoon, keeping them open to facilitate ventilation. Prevent accumulated heat in the shed from burning the bags, or long-term dampness from affecting moisture discharge, allowing the bags to evaporate water during summering under ventilated conditions, losing 20-30% of their weight at cultivation time, which helps promote uniform fruiting through wet-dry differences.
5. Comprehensive bud forcing. Before forcing fruiting of the bags, use the "dehydration and color change" piercing method, select one side of the bag and pierce two rows of holes, soak in water for 2-3 hours, and after the second flush, soak for 4-12 hours. After soaking, wrap tightly with shed film, increase temperature in sunlight, prompt the temperature to reach 32°C and maintain for 2-4 hours, then stimulate with low temperature of 8-12°C at night for 2-3 hours, then seal and keep warm at 15-24°C and fumigate for 2-3 days to fruit. Alternatively, place the soaked bags in the upper three layers of the fruiting shed, and use sunlight or underground flues or mushroom cultivation machines to increase temperature, with management the same as above. However, fruiting is not as fast and uniform as the former, but it saves labor compared with the former.
6. Heating to force buds. In low-temperature seasons, use the "comprehensive bud forcing" method, place the bags upright in two layers indoors, cover tightly with shed film, and heat by placing a coal stove with a kettle under the shed film, maintaining the temperature at 20-26°C, and fruiting can occur in 2-4 days.
After fruiting, select the bags once a day and place them into the fruiting shed, keep the temperature in the shed above 8°C, spray to maintain about 80% humidity, cut the film and select buds to set the fruiting bodies, and carry out fruiting management.