Cultivation Techniques for Shiitake Mushrooms Intercropped in Fast-Growing Plantations in Beijing
In order to protect and improve the ecological environment of the capital, artificial fast-growing plantations in the suburbs of Beijing have developed rapidly in recent years. Because the time required to grow timber is relatively long, there is a contradiction between farmers' short-term benefits and the long-term benefits of afforestation, which has affected farmers' enthusiasm for planting trees and establishing forests. Therefore, effectively using idle land resources between the trees to develop edible mushroom production is an effective way to accelerate the prosperity of afforestation farmers. Taking shiitake mushrooms as an example, this paper introduces cultivation techniques for intercropping edible mushrooms in fast-growing plantations.
1 Selection of cultivation site
The fruiting body development stage of shiitake mushrooms intercropped in woodland occurs in the forest. Moderate scattered light is beneficial for producing mushrooms with thick flesh, short stipes, plump caps, and deep, glossy color. Therefore, the cultivation site is generally chosen in a forest with a row spacing of 6 m, a tree spacing of 3 m, a tree age of more than 5 years, and a canopy density of about 0.7, requiring flat terrain and convenient water sources.
2 Cultivation season
Arrange the cultivation season according to local climatic conditions and the forest canopy situation. Generally, production in the forest begins when the woodland starts to close its canopy and ends before leaf fall. In the Beijing area, stock cultures or spawn for cultivation are generally prepared from late February to early March, cultivation bags are made in mid-to-late March, and from mid-May to early June the spawn-run bags are placed in batches into the woodland for fruiting, ending in mid-September.
3 Variety selection
The cultivation period coincides with high summer temperatures, so excellent high-temperature-type strains should be selected. Such as Wuxiang No. 1, L935, Hanxiang L266, Xiagu No. 1, Xiagu No. 2, etc.
4 Preparation of fungus sticks
4.1 Cultivation substrate formulas Formula 1: 54% mixed hardwood sawdust, 25% broadleaf tree sawdust, 20% wheat bran, 1% gypsum, 3 per mille magnesium sulfate or Gufengsu; Formula 2: 55% mixed hardwood sawdust, 24% cottonseed hulls, 18% wheat bran, 2% gypsum, 41% magnesium sulfate; Formula 3: 80% cottonseed hulls, 18% wheat bran, 1% gypsum, 1% white sugar; Formula 4: 45% cottonseed hulls, 32% corncobs, 20% wheat bran, 1% white sugar, 1% superphosphate, 1% gypsum. When combining cultivation raw materials, formulas can be selected flexibly according to local conditions. When preparing materials, the main ingredients must be fresh and free from mold. Cottonseed hulls contain a small amount of gossypol, which is unfavorable to the growth of shiitake mushroom mycelium. Before use, they can be soaked in 0.5%-1% limewater until saturated, then piled and fermented for 5-7 days, and rinsed with clean water until pH 6.0-6.5 before use.
4.2 Mixing materials Mix and stir various dry materials evenly. Magnesium sulfate, Gufengsu, and white sugar should first be dissolved in water and then added while stirring, adding clean water and stirring repeatedly until uniform with no lumps, and a water content of 55%-60% is sufficient.
4.3 Bagging and sterilization After the cultivation substrate is mixed, it can be bagged after half an hour. Use polyethylene bags with a length of 55-60 cm, a width of 15 cm, and a thickness of 0.05 mm. Fill the bags firmly without breaking them, tie the openings with string, and make the substrate bag about 40 cm long. Use normal-pressure steam sterilization, maintaining 100°C for 15-20 hours.
4.4 Inoculation and spawn running After sterilization, cool the fungus bags to about 25°C, inoculate according to aseptic operation requirements, with an inoculation amount of about 10%. After inoculation, move the cultivation bags into the spawn-running room, stack them in a crisscross pattern, 4 bags per layer, stacking 6-8 layers. The room should be dark, with a temperature of 20-25°C, relative air humidity below 60%, and frequent ventilation. Turn the bags once every 10-15 days, removing seriously contaminated bags. After about 50-60 days, the mycelium fills the bags, and raised areas and partial color change appear.
5 Moving into the forest for fruiting
5.1 Building cultivation sheds Before the fungus sticks are moved into the forest, clean the woodland thoroughly and level the ground. Along the rows between trees, build small arched sheds with bamboo and wood materials, with a shed width of 2-2.5 m and a height of 1-1.2 m, and the length depending on circumstances, covering the sheds with plastic film. Inside the shed, use bamboo poles or wire to set up mushroom racks lengthwise 25 cm above the ground for placing fungus sticks, with a row spacing of 20 cm, totaling 10-12 rows. Along the length of the shed, install 1 micro-sprinkler tape at the top of the shed, with 1 nozzle every 2 m. Build a shade canopy about 2.5 m above the beds (shade netting or straw and other materials may be used), with the edge of the shade canopy preferably extending 2 m beyond the perimeter of the beds, so that sunlight from 9:00 to 16:00 cannot directly shine on the mushroom beds.
5.2 Bag removal and color change Remove the bags when about 1/4 of the surface of the fungus sticks has changed color. Before bag removal, spray the ground with clean water or 5% limewater to increase humidity. After bag removal, lean the fungus sticks at 70° against the mushroom racks and cover with the shed film. Maintain a temperature of 15-23°C, spray water 2-3 times a day, provide appropriate scattered light, and avoid strong direct light on the fungus sticks. Do not ventilate on the 1st-2nd days after bag removal, then ventilate 1-2 times a day, about 1 hour each time. When the fungus sticks exude yellow water, spray a fine mist the first day to dilute the yellow water, and the next day use a stronger water stream to rinse away the yellow water. Generally, color change is completed in about 15 days.
5.3 Fruiting management Doing a good job of temperature control is the key to forest-mushroom intercropping. Shiitake mushroom mycelium is not tolerant of high temperatures. When the ambient temperature exceeds 35°C for more than 4 hours, the mycelium begins to age, self-digest, the fungus sticks soften, and the sticks may even be burned and rotted. After the fungus sticks change color, maintain the temperature at 15-30°C, while increasing the day-night temperature difference to more than 10°C to stimulate the formation of mushroom buds. Normally spray mist water 2-3 times a day, and maintain air humidity at 85%-95%. Ventilate 1-2 times a day, about 1 hour each time.
5.4 Timely harvesting Because the ambient temperature is relatively high, shiitake mushrooms grow quickly and easily open their caps. The best harvesting time is when the cap has not fully opened, the cap margin is slightly incurved to form a "copper gong edge," and the gills have fully extended and changed from white to light yellowish brown. When harvesting, pick the large ones and leave the small ones, avoid damaging small mushroom buds, and be careful not to leave mushroom stubs. After each flush is harvested, enter the mycelium recovery stage, stop spraying water for 3-5 days, appropriately raise the temperature, reduce the day-night temperature difference, and lower the relative air humidity to 70%-80%. After 7-10 days of mycelium recovery, enter the next flush's stimulation and fruiting management.
5.5 Water supplementation for fungus sticks In the middle and late fruiting stages, the fungus sticks lack water and fruiting becomes difficult, so timely water supplementation is needed. A needle-type water injection method can be used, so that after injection the fungus sticks reach about 95% of their original weight. Other management measures are basically the same as those in the earlier fruiting management.