Technique for Cultivating Shiitake Mushrooms on Discarded Mulberry Branches in Northern China
Shiitake mushrooms belong to the fungal edible mushrooms, with very high medicinal and culinary value and promising market prospects. After the Agricultural Technology Center of Qianyang County, Shaanxi Province introduced this technique in 1999 and successfully tested it at the county's original seed farm, 44 farmers from 10 villages including Caojiayuan began engaging in shiitake mushroom production. According to 6 years of statistical data, apple orchards (including mulberry orchards) with trees aged 8 to 15 years yield an average of 500 kg of discarded old trees and pruned branches per mu per year that can be crushed into sawdust, producing 625 kg of fresh shiitake mushrooms, @#@136@#@ with revenue of about 2,500 yuan.
I. Scale and Forms
This technique is suitable for single-household or joint-household production, and can also be used to establish a production site by purchasing old trees and branches. The scale can range from 5,000 bags up to tens of thousands of bags.
II. Facilities and Raw Materials
1. Facilities and equipment: Build a plastic arched shed, construct an atmospheric-pressure sterilization stove and a drying stove, and prepare a clean water source; purchase a three-phase electric dedicated wood chipper, sprayer, inoculation box and tools; purchase a certain number of meters (or kilograms) of polypropylene edible mushroom cultivation bags, 12 cm in diameter and 0.045 cm thick in roll form, cut into 55 cm lengths; additionally prepare some plastic tying cord or a heat sealer.
2. Four raw materials: Fresh apple tree or mulberry tree wood and branches crushed into sawdust, wheat bran, gypsum powder, and nutrients. Taking the mixed dry weight ratio of 1,000 kg as an example: sawdust 840 kg : wheat bran 150 kg : gypsum 10 kg : nutrients 5 kg.
III. Season and Varieties
Bag-cultivated shiitake mushrooms are divided into spring planting and autumn planting, with spring planting and autumn-winter harvest yielding the best benefits. Spring planting runs from mid-March to early March of the following year to complete one cultivation year, with 5 harvests of mushrooms. Spring planting varieties should be low-temperature tolerant types, and the optimal spawn age for cultivation spawn is 120-160 days.
IV. Eight Steps of Cultivation and Production
1. Mixing ingredients and bagging: First mix the sawdust, wheat bran, gypsum powder and nutrients thoroughly according to the formula ratio, then add an appropriate amount of clean water, adjust the moisture and mix evenly. That is, when squeezed by hand it forms a ball, and when dropped it breaks apart, with a neutral pH value. Put the mixed cultivation material into plastic bags by hand or with a bagging machine, making sure to fill tightly and firmly, with a bag weight of 5.0-5.5 jin being appropriate, and be careful not to tear the bags. The two ends of the bag opening can be tied tightly with string or heat-sealed.
2. Sterilization and inoculation: Place the filled bags in layers in a crisscross arrangement into the atmospheric-pressure steam sterilization stove, bring the water in the stove to 100°C and maintain it for more than 24 hours to ensure thorough sterilization. Pay attention to adding hot water to prevent the stove from drying out or steam from escaping. After sterilization, take the bags out of the stove, sort out the intact good bags and place them in a disinfected room to stack and cool. When the bag temperature drops to about 25°C, inoculate in the inoculation box. On average, inoculate 12 points per bag log, with a hole depth of 3 cm, and insert one piece of spawn the size of a jujube pit. After inoculation, seal each bag opening with melted wax. Before inoculation, the bag surface should be disinfected with a 5% Lysol solution.
3. Warmth-preserving cultivation: Immediately move the inoculated and sealed spawn bags into a disinfected cultivation room and stack them neatly. A stack height of 5-7 layers is appropriate. Keep the temperature in the cultivation room stable at about 25°C, keep the room dry and ventilated, control relative humidity below 70%, and keep it dark. When the mycelium grows to about 4 cm, promptly turn and reposition the stacks, and use a disinfected fine needle to prick a small number of holes to increase oxygen. At this stage, pay attention to moisture-proofing and mold prevention, and keep the temperature uniform from top to middle to bottom of the stacks.
4. Pricking holes and placing on shelves: After the mycelium has fully covered the entire bag, begin pricking holes in the whole bag to increase oxygen from the 10th to 15th day, and place them indoors or in cave dwellings to overwinter the summer, with the temperature controlled below 28°C; if overwintering the summer in an outdoor shed, choose a wind-sheltered, sun-facing location in advance and build a plastic arched shed mushroom shelf, covering the shed with a shade net. Move the pricked spawn bags into the mushroom shed and arrange them on the shelves.
5. Color turning and development: After the shiitake mycelium has fully covered the entire bag and been cultivated for 60-80 days, it enters the color-turning management period. The color-turning standard is: brown with white spots, the mushroom skin not thick, and the spawn log weight slightly reduced. During the color-turning period, the suitable temperature in the shed is 20-24°C. Spraying water on the ground should be used to raise air humidity to 85%-90%, while also requiring scattered weak light and fresh air.
6. Mushroom induction and budding: In the late color-turning stage, do not move the spawn logs, so as to promote full maturation of the mycelium inside the logs. Strengthen ventilation and air exchange, and use a small blade to cut the spawn bags to release the yellow water inside. At this stage, pay special attention to preventing pathogen infection, and take measures such as digging out the diseased parts or applying medicinal solution. If the infection is severe, move them out and burn or bury them deeply. For mushroom induction, uncover the shed in the morning and evening and cover it at noon to create a temperature difference of more than 10°C. The timing of mushroom induction should be controlled for when the autumn temperature drops below 18°C (generally during the @#@245@#@ sowing period). For spawn bags with suitable water content, use vibration and tapping to break and thicken the shiitake mycelium and produce mushroom buds; for spawn bags with lower water content, replenish water to induce budding, and after replenishing water make the water content of the spawn bags 50%-60%.
Generally, the first harvest all requires vibration to induce budding; the following four harvests do not require vibration, and only need water replenishment to achieve the purpose of inducing buds. After bud induction forms young mushroom protrusions, promptly cut the bags to release the mushrooms. After the young mushrooms are released, control temperature (8-18°C) and humidity (relative humidity 85%) well to ensure normal growth and development of the mushroom buds. Also promptly thin the buds, with a spacing of 6 cm between plants and rows as the standard. In order to obtain high-priced flower shiitake mushrooms, the alternating dry-wet method can be used to cause physiological cracking of the mushroom caps to cultivate flower shiitake mushrooms.
7. Harvesting by flush, drying and freshness preservation: The standard for superior mushrooms is a shiitake cap diameter of 6-8 cm. The harvest timing is when the mushroom veil is about to break or has just broken, the cap edge curls inward to form a "gong edge," and the gills have fully extended and turned from white to light yellow. When harvesting, sort by size and sell separately. Flower shiitake mushrooms should be dried for external sale. After the first harvest is completed, through measures such as cultivating the mycelium and replenishing water, repeat the management method of the first harvest until the final fifth harvest of shiitake mushrooms, and the entire annual production is completed. Shiitake mushrooms for external sale, flower shiitake mushrooms, and fresh shiitake mushrooms that cannot be sold fresh should be promptly put into the stove for drying, graded by size and quality, and packed separately in special freshness-preserving bags for wholesale (for example: Henan, Sichuan and other places).