Straw Mushroom Cultivation Techniques and Cultivation Management Methods Explained in Detail
The straw mushroom has tender flesh, is crisp and smooth, delicious in taste, and rich in nutrients, with excellent health benefits, making it a high-quality edible mushroom. Whether fresh, dried, or canned, its products are deeply loved by consumers in domestic and international markets. Especially in the hot summer weather, when other edible mushrooms are scarce, it is precisely the peak season for straw mushrooms, which also coincides with the off-season for vegetables. Therefore, it can not only enrich people's shopping baskets but also commands a relatively high price, offering good economic returns. The straw mushroom is the fastest-harvesting among edible mushrooms, requiring only about 2 weeks from spawning to harvest, with a cultivation cycle of just 20-30 days. Moreover, it requires no special equipment and can be cultivated both indoors and outdoors. Developing straw mushroom cultivation can utilize agricultural by-products such as cottonseed hulls, rice straw, sugarcane bagasse, and corn stalks as cultivation substrates.
Growing Conditions for Straw Mushrooms
1. Nutrition: The nutrients required for the growth and development of straw mushrooms are mainly carbohydrates, nitrogen nutrition, and minerals, in addition to a certain amount of vitamins. These substances can generally be obtained from materials such as rice straw or cottonseed hulls. The straw mushroom is a saprophytic fungus, and it must absorb nutrients from dead plant matter and soil. For cultivating straw mushrooms, raw materials such as rice straw and cottonseed hulls that are free from mold and deterioration should be selected. Wet straw that has not been sun-dried is prone to rotting and should not be used. In addition, waste cotton, sugarcane bagasse, green thatch grass, and peanut vines can all be used as raw materials for cultivating straw mushrooms. If an appropriate amount of supplementary materials such as dried cow manure, chicken manure, wheat bran, rice bran, and corn flour is added to the above raw materials to supplement nitrogen nutrition and vitamins, the yield of straw mushrooms can also be increased.
2. Temperature: The straw mushroom belongs to the high-temperature fungal category. The temperature range for mycelial growth is 10-42°C, with the optimum temperature being 28-32°C. Growth stops at 10°C, and above 45°C or below 5°C, the straw mushroom mycelium will die. Straw mushroom spawn should not be stored in a refrigerator to avoid freezing to death. The temperature range for fruiting body growth is 22-40°C, with the optimum temperature being 28-32°C. When the average temperature is below 23°C, fruiting bodies are difficult to form. When the substrate temperature is below 28°C, fruiting body formation is affected, and below 25°C, fruiting bodies are difficult to form. Temperatures below 21°C or above 40°C, as well as sudden climate changes, have a fatal effect on small mushroom buds. Fruiting bodies are extremely sensitive to sudden temperature changes; if the substrate temperature changes by more than 5°C within 12 hours, the straw mushroom is prone to dying.
3. Humidity: The straw mushroom is a fungus that thrives in high-temperature and high-humidity environments. Only under suitable moisture conditions can the straw mushroom grow and develop normally. Insufficient moisture leads to slow mycelial growth and difficulty in fruiting body formation; excessive moisture causes poor aeration, makes mushrooms prone to dying, and also makes contaminating fungi more likely to occur. The optimal moisture content of the substrate is about 70%, the optimal air humidity during the mycelial growth stage is about 80%, and the relative air humidity during the fruiting body growth stage is required to be above 90%.
4. Oxygen: The straw mushroom is an aerobic fungus, and sufficient oxygen is an important condition for its growth. If oxygen is insufficient and carbon dioxide accumulates too much, fruiting bodies will be inhibited or even die. Contaminating fungi are also more likely to occur. Therefore, during the management of straw mushroom cultivation, attention should be paid to ventilation and air exchange to keep the air fresh. However, moisture retention should also be attended to, and the relationship between ventilation, moisture retention, and heat preservation must be correctly handled.
5. pH Value: The straw mushroom is a fungus that prefers alkaline conditions. The optimal pH for straw mushroom mycelial growth is 7.8-8.5, and the optimal pH for fruiting body growth is 7.5-8. An acidic environment is unfavorable for the growth and development of mycelium and makes it more susceptible to contamination by other fungi. During cultivation, lime is generally added to adjust the pH value, with the addition amount typically being about 5% of the dry material weight, bringing the pH to 10-12. As the mycelium grows, the pH value gradually decreases. By the time fruiting bodies form, the pH value is around 7.5, which is exactly suitable for the growth and development of straw mushroom fruiting bodies.
6. Light: The germination of straw mushroom basidiospores and mycelial growth do not require light; direct sunlight actually hinders mycelial growth. However, light promotes fruiting body formation. Fruiting body formation requires a certain amount of scattered light, with the optimal light intensity being 300-350 lux. The intensity of light not only affects the yield of straw mushrooms but also directly affects the quality and color of the fruiting bodies. Under strong light, the fruiting bodies are dark in color and glossy, with dense and firm tissue; under insufficient light, the fruiting bodies are dull or even grayish-white, with looser tissue. Without light, the fruiting bodies are white. Strong direct sunlight severely inhibits fruiting bodies, and open-field cultivation must have shading conditions.
Cultivation Season for Straw Mushrooms
The cultivation season for straw mushrooms under natural conditions should be determined based on the temperature required for their growth and development and the local temperature conditions. Generally, cultivation can only begin when the daily average temperature reaches above 23°C. In southern China, the natural temperature cultivation period is from late May to mid-September on the Gregorian calendar. Cultivation from early June to early July is most favorable, as the temperature is suitable at this time, and it coincides with the plum rain season with high humidity, making temperature and humidity easy to control, yielding high production and good mushroom quality. In midsummer (mid-July to late August), the temperature is relatively high and dry, with a large amount of water evaporation. Management is more difficult, and achieving high yield and quality of straw mushrooms is more challenging. In provinces such as Guangdong and Hainan, cultivation of straw mushrooms under natural temperature conditions is more suitable from April to October. In northern regions, cultivation from June to July is preferable. When using greenhouses or plastic sheds for cultivation, the timing can be advanced or delayed as appropriate. If foam mushroom houses with heating equipment are used, year-round production is possible.
Straw Mushroom Cultivation Varieties
Based on color, there are two major strains: one is called black straw mushroom, whose main characteristic is that the unopened fruiting body wrapper is mouse-gray or black, oval in shape, not easily opening, with a relatively small base, making it easy to pick. However, it has poorer stress resistance and is particularly sensitive to temperature changes. The other is called white straw mushroom, whose main characteristic is that the fruiting body wrapper is grayish-white or white, with a thin wrapper that opens easily, a relatively large base, making it more difficult to pick, but it fruits quickly, has high yield, and strong stress resistance. Based on the individual size of straw mushrooms, they can be divided into large, medium, and small types. Due to different uses, the requirements for straw mushroom varieties also differ. For making dried straw mushrooms, large types with thick wrappers are preferred; for canning, medium and small types with thick wrappers are needed; for fresh-sale straw mushrooms, there are no strict requirements on wrapper thickness and individual size. Each locality can select suitable varieties for cultivation according to its needs.
Preparation of Straw Mushroom Substrate
The raw materials for cultivating straw mushrooms are extensive, mainly utilizing materials rich in cellulose and hemicellulose. Such as waste cotton residue, cottonseed hulls, rice straw, and wheat straw. Waste cotton residue gives the highest yield. The following introduces several commonly used substrate formulas:
1. Preparation of Waste Cotton Residue Substrate
Waste cotton residue, also called waste cotton, broken-seed cotton, fallen cotton, or floor cotton, comes from cotton processing plants. Waste cotton residue has a long heating period and good heat and moisture retention properties, making it currently the most ideal straw mushroom cultivation material. About 12 kg of waste cotton residue is needed per square meter. Commonly used formulas include:
① Waste cotton residue + 5% lime
② Waste cotton residue + 10% bran (or rice bran) + 5% lime powder
There are two methods for preparing the substrate: One method is to build a pool, soak the waste cotton residue in lime water with 5 kg of lime powder added per 100 kg of waste cotton residue, soak for 5-6 hours, then scoop it out and pile it up, with a pile width of 1.2 m, a pile height of about 70 cm, and unlimited length, ferment for three days, turning the pile once in between. The other method is to make a wooden frame, 3.0 m long, 1.8 m wide, and 0.5 m high, placed on a concrete floor. Then spread a layer of waste cotton residue in the wooden frame, about 10-15 cm thick, sprinkle a thin layer of lime powder, sprinkle water and press down to make the waste cotton residue absorb enough water, then sprinkle a layer of bran or rice bran, spread another layer of waste cotton residue, and so on layer by layer, pressing down until the frame is full. Then lift the wooden frame upward and continue adding material and pressing down until the pile height reaches about 1.5 m. Ferment for 3 days.
2. Preparation of Cottonseed Hull Substrate
Cottonseed hulls, also called cottonseed skin, are also a relatively nutrient-rich straw mushroom cultivation material, but their heat and moisture retention and heat generation capacity are not as good as waste cotton residue. The substrate formula is the same as for waste cotton residue. In addition to the above two treatment methods, cottonseed hulls can also be spread on a concrete floor, with lime powder or supplementary materials added, thoroughly mixed with water, then piled up, covered with plastic film, and fermented for three days, turning the pile once in between. When turning, if the pile is too dry, lime water should be added to adjust. When transferred to the bed, the moisture content of the material should be about 70%, and the pH value should be 8-9.
3. Preparation of Rice Straw or Wheat Straw Substrate
Rice straw and wheat straw are abundant raw materials and are traditional straw mushroom cultivation materials. Since the physical properties of rice straw and wheat straw are relatively poor and their nutrients are lacking, proper treatment and the addition of supplementary materials can still achieve relatively good yields. 10-15 kg of dry rice straw is needed per square meter.
① 87% rice straw or wheat straw + 5% plant ash + 1% compound fertilizer + 2% gypsum powder + 5% lime;
② 88% rice straw or wheat straw + 5% bran or rice bran + 2% gypsum powder + 5% lime;
③ 73% rice straw or wheat straw + 5% dried cow manure + 15% fertile soil + 2% gypsum powder + 5% lime;
④ 83% rice straw or wheat straw + 5% bran + 5% dried cow manure + 2% gypsum powder + 5% lime
There are two treatment methods for the above rice straw or wheat straw: One method is to not cut the rice straw or wheat straw and use long rice straw for cultivation. Soak the rice straw for about 12 hours, with a heavy object placed on top of the rice straw to ensure full water absorption. After soaking thoroughly, scoop it out and pile it up, with a pile width of 2 m, a pile height of 1.5 m, covered with plastic film for moisture retention, pile and ferment for 3-5 days, turning the pile once in between. During cultivation, the long rice straw should be twisted into a "figure-8" shape and tied tightly into bundles, arranged closely one bundle at a time, stacked in two layers in a "pin" shape, with a thickness of 20 cm. The other method is to cut the rice straw or wheat straw into 5-10 cm lengths or crush them with a grinder, soak them or directly mix them with lime water, and add supplementary materials, pile for 3-5 days, turning the pile once in between.
4. Preparation of Mixed Substrate
In order to reduce production costs, the cultivation method of using waste cotton residue or cottonseed hulls plus rice straw or wheat straw can be adopted, and relatively ideal results can also be achieved. The mixing ratio is usually 1/3-2/3 waste cotton residue or cottonseed hulls, with rice straw cut into sections or crushed, and lime and supplementary materials added before piling and use.
Straw Mushroom Bed-Style Cultivation Techniques
Straw mushroom shelf-type cultivation is currently a commonly used cultivation method in China. Building shelves in a house or shed not only fully utilizes space and improves utilization rates but also provides good moisture and heat retention, is easy to manage, and yields high and stable production.
1. Construction of Bed Shelves: Straw mushroom cultivation bed shelves are the same as mushroom cultivation bed shelves. The bed shelves should be arranged perpendicular to the mushroom house, that is, in an east-west oriented mushroom house, the bed shelves are arranged north-south. The bed shelves should not lean against the walls on all sides. The walkway along the wall should be 50 cm wide, the walkway between bed shelves should be 67 cm wide, the distance between each layer of the bed shelf should be 67 cm, and the bottom layer should be at least 17 cm above the ground. The number of bed shelf layers depends on the height of the mushroom house, generally 4-6 layers, and the bed shelf width is 1.3-1.5 m. The bed shelves can be made of bamboo or wood, and reinforced concrete bed shelves are even better. At both ends of each walkway, a pair of upper and lower windows should be opened on each wall. The window size should preferably be 40 cm wide and 50 cm high. A ventilation chimney should be installed on the roof in the middle of the walkway between bed shelves, 1.5 m high and about 40 cm in diameter.
2. Secondary Fermentation of Substrate: Loosen and mix the substrate that has undergone pile fermentation, and move it onto the bed shelves in the mushroom house while hot. At this time, the moisture content of the substrate should preferably be about 70%, and the pH value should be about 9. The substrate thickness varies for different cultivation raw materials. For waste cotton residue or cottonseed hull substrate, the general substrate thickness is 7-10 cm; for chopped rice straw substrate, the substrate thickness is 12-15 cm; for long rice straw, the substrate thickness is 20 cm. When the summer temperature is high, the substrate should be spread appropriately thinner. When the winter temperature is low, the substrate should be spread appropriately thicker. After spreading the substrate, immediately introduce steam into the mushroom house or place a coal stove for heating, bringing the cultivation temperature to about 65°C, maintaining for 4-8 hours, then allowing it to cool naturally. When it drops to about 45°C, open the doors and windows. Secondary fermentation can kill pests and harmful contaminating fungi in the mushroom house and substrate, is conducive to the massive reproduction of beneficial microorganisms such as high-temperature actinomycetes, and is more conducive to straw mushroom growth, making it easy to achieve high yields.
3. Spawning and Post-Spawning Management
When the substrate temperature drops below 38°C, loosen and mix the substrate, level the bed surface, compact it, and then proceed with spawning. Remove the spawn from the spawn bottles; for bagged spawn, tear off the plastic, place the spawn in a clean basin, gently break the spawn blocks into pieces. The method of spot-spawning combined with broadcast-spawning is best. The spacing for spot-spawning is 3 cun (about 10 cm) square. The remaining 1/5 of the spawn is broadcast on the surface of the substrate and gently patted flat with a wooden board. Generally, 300-400 bottles (750 ml) of spawn are needed for 100 square meters of cultivation area.
After spawning, cover the bed surface with plastic film and uncover it 1-2 times daily for ventilation, paying attention to controlling the temperature inside the substrate. The temperature inside the substrate undergoes a process of changing from low to high and then from high to low. After spawning, the substrate temperature gradually rises, generally reaching the highest temperature in 3-4 days. The maximum temperature inside the substrate should be controlled below 42°C as much as possible; otherwise, if the temperature is too high, a large amount of water in the substrate evaporates, and the straw mushroom mycelium is severely inhibited or dies. If the substrate temperature is too high, the cause should be analyzed promptly and measures taken to resolve it. If the substrate moisture is insufficient and the substrate is too dry, water should be sprinkled to supplement moisture and lower the temperature; if the substrate is too thick, indoor ventilation should be strengthened, the plastic covering the substrate surface should be lifted, and holes should be made in the substrate to dissipate the substrate temperature.
About 4 days after spawning, remove the plastic covering the substrate surface. It is best to cover with a thin layer of pre-moistened long rice straw, or pre-moistened rice husks, or cover with about 1 cm thick granular soil, and spray 1% lime water, which can also increase the yield of straw mushrooms.
4. Fruiting Period Management. Generally, 5-6 days after spawning, when the straw mushroom mycelium begins to knot, promptly increase the moisture on the substrate surface, apply the "fruiting water" well, and increase indoor light to promote the formation of straw mushroom fruiting bodies. When a large number of small white dot mushroom buds form, focus on moisture retention, maintain relative air humidity above 90%, and temporarily stop spraying water on the bed surface. When the fruiting bodies are the size of a button, gradually increase the amount of water sprayed.
Straw Mushroom Raised-Bed Cultivation Techniques
Raised-bed cultivation of straw mushrooms is a commonly used outdoor open-field cultivation method. Its characteristics are low investment, low cost, high flexibility, and simple operation. With good management, relatively high yields can be obtained.
The best site for outdoor straw mushroom cultivation is loose, fertile, well-drained sandy loam soil. This type of soil has good heat retention, moisture retention, nutrient storage, and aeration properties, which are conducive to the growth and development of straw mushroom mycelium and fruiting bodies. Rice fields, vegetable plots, orchards, forest land, and vacant spaces in front of and behind houses can all serve as sites for straw mushroom cultivation. Rice fields have fewer earthworms and contaminating fungi, which is conducive to the growth and development of straw mushrooms. When the temperature is low, a wind-sheltered, sunny location should be chosen; when the temperature is high, cultivation should be done in cool, ventilated shade sheds, melon sheds, or under trees, which can achieve relatively ideal yields.
After selecting the cultivation site, first plow the land once, generally 15-20 cm deep, expose it to the sun for 2-3 days, then level the land and make raised beds. The bed height is 15-20 cm, the bed width is about 1 m, generally 5-6 m long, and the walkway between beds is 50 cm wide. Make soil ridges about 10 cm wide and 10 cm high around and in the middle of the beds to produce more ground mushrooms. If the terrain is low, deep ditches should be dug around the field for drainage. For high and dry terrain, low beds should be made, with the walkway about 20 cm higher than the bed for moisture retention.
After the bed surface is prepared, since the bed soil is relatively dry, water should be irrigated or sprinkled on the bed surface one day before adding the substrate to thoroughly wet the soil, or tea-seed cake water, ammonia water, or bleaching powder water can be applied directly to the bed surface to eliminate pests and contaminating fungi. Then sprinkle a layer of lime powder on the bed surface and spray insecticide to eliminate soil pests and contaminating fungi.
After the cultivation bed is disinfected, move the pre-piled and fermented substrate onto the bed surface, laying the substrate directly on the soil. The substrate should be thicker than that used for indoor bed-style cultivation. For waste cotton residue or cottonseed hull substrate, the substrate thickness is about 10 cm; for chopped rice straw substrate, 15-18 cm is needed; for long rice straw, about 20 cm of substrate is needed. After spawning, especially for rice straw substrate, it is best to cover the substrate surface with a layer of fine soil about 2 cm thick. Then cover with plastic, uncovering it 1-2 times daily.
After spawning, build a ring-shaped arch frame on the bed surface using bamboo strips and fence bamboo, with the center of the frame 50 cm above the bed surface. Cover the frame with plastic, and then cover the plastic with a shade net or rice straw mat. This can prevent direct sunlight on the bed surface while also providing heat and moisture retention. The spawning method and post-spawning management are the same as for indoor bed-style cultivation.
Straw Mushroom Bag Cultivation Techniques
Straw mushroom bag cultivation is a relatively new cultivation method and is a high-yield straw mushroom cultivation method, with unit yield about 1 times higher than traditional pile-straw cultivation. The biological efficiency can reach 30-40%.
1. Soaking Straw: Cut rice straw into 2-3 sections; if conditions permit, cut into about 5 cm lengths, and soak in 5% lime water for 6-8 hours. The water used for soaking rice straw can be reused 2 times, with lime must be added each time.
2. Mixing Substrate: Scoop out the rice straw and place it on a slightly sloped concrete floor, spread it out to drain excess water, or wring it dry by hand. When you grip the rice straw tightly and one or two drops of water drip down, that is the appropriate moisture level, with a moisture content of about 70%. Then add supplementary materials and mix evenly, ensuring that the various supplementary materials are evenly distributed and adhered throughout the rice straw. Commonly used formulas for mixing include the following:
① About 87% dry rice straw + 10% bran + 3% peanut cake powder or soybean powder + 0.1% monopotassium phosphate.
② About 85% dry rice straw + 10% rice bran + 3% corn flour + 2% gypsum powder + 0.2% monopotassium phosphate.
③ 83.5% dry rice straw + 10% rice bran + 3% peanut cake powder + 2% gypsum powder + 1.5% compound fertilizer.
④ 56.5% dry rice straw + 30% fertile soil + 10% rice bran + 2% gypsum powder + 1.5% compound fertilizer.
3. Bagging: For the thoroughly mixed substrate, use 24 cm × 50 cm polyethylene plastic bags. Tie one end of the bag tightly with a slip knot using thick cotton thread, tying at 2 cm from the bag opening. Put the mixed substrate into the bag, pressing firmly while filling, with each bag holding 2-2.5 kg wet weight of substrate. Then tie the bag opening tightly with a slip knot using cotton thread.
4. Sterilization: Use atmospheric pressure sterilization. After loading the pot, heat with high fire to bring the temperature inside the pot to 100°C as quickly as possible, maintain at 100°C for about 6 hours, then stop the fire and remove from the pot, moving to the inoculation room.
5. Inoculation: Use aseptic room or inoculation box for inoculation. The disinfection treatment of the aseptic room or inoculation box is the same as for other edible mushrooms. During inoculation, untie the string at one end of the substrate bag, inoculate with straw mushroom spawn, and retie the string. Untie the string at the other end, similarly inoculate with spawn, and retie the string. One bottle (or one bag) of spawn can inoculate about 12 bags.
6. Mycelial Growth Management: Move the inoculated spawn bags into the cultivation room, arrange them on cultivation shelves or stack them on the ground. The stacking height of spawn bags should be determined according to the season. When the temperature is high, the number of stacked layers should be fewer; when the temperature is low, the number of stacked layers can be appropriately increased. Generally, stacking 3-4 layers is appropriate. The temperature of the cultivation room should preferably be controlled at 32-35°C. Four days after inoculation, when the mycelium in the spawn bag has colonized 2-3 cm of substrate, loosen the tied string at the bag opening somewhat to increase oxygen inside the bag and promote mycelial growth. Under suitable conditions, the mycelium usually covers the entire bag in 10-13 days.
7. Fruiting Management: Move the spawn bags fully covered with mycelium into the cultivation room, roll up the bag openings, arrange them on bed shelves or stack them wall-style in 3-5 layers, cover with plastic film, and increase the relative air humidity of the cultivation room to about 95%. After 2-3 days of management, mushroom buds begin to form, and at this point the plastic film can be lifted. Only when the mushroom buds grow to the size of a small button can water be sprayed onto the spawn bags. When the mushroom buds grow to the egg-shaped stage, they are ready for harvest. Generally, 2-3 flushes of mushrooms can be harvested.
Plastic Foam House Year-Round Cultivation Techniques
Plastic foam house cultivation is the main method for year-round straw mushroom cultivation. It has good heat and moisture retention properties, can insulate against heat in summer and can be heated in winter. It requires low investment, has low cost, fewer contaminating fungi, and high yield.
There are many types of plastic foam houses, and currently there are mainly two types, introduced as follows:
1. Two-Bed Type
The mushroom house is 5 m long and 2.2 m wide, with two rows of bed shelves, each row having 4 layers. The mushroom house has a wooden frame structure with a "figure-8" shaped roof. First build the bed shelves, then cover with plastic film and foam boards. The bed shelf frame is built with Chinese fir square timber, with specifications generally 4 cm × 4 cm or 3 cm × 3 cm. Each bed shelf is 70 cm wide, the distance between layers is 0.6 m, and the bottom layer is about 0.4 m above the ground. The walkway between bed shelves is about 0.6 m wide. After the bed shelves are built, cover the outer sides and top of the bed shelves with plastic film, and after covering with plastic, seal with foam boards. The thickness of the foam boards should preferably be 2.5-3 cm. Seal the plastic film joints with plastic tape. The joints between two foam boards should be pressed firmly and nailed securely with Chinese fir strips. Open one door and window at each end of the walkway. For the top layer of the mushroom house, in addition to covering with plastic and foam boards, it is best to cover with a layer of asbestos tiles if conditions permit.
The walkway of the foam house has an underground stove built with a diameter of 0.3 m and a depth of 0.5 m. The stove bottom has a grate, with an air inlet and an exhaust outlet. The air inlet has a pipe leading to outside the mushroom house, and the exhaust outlet is connected to a heating pipe, which extends along the walkway all the way to outside the wall at the other end of the mushroom house. Half of the pipe is below the ground surface and half is above the ground surface. The upper part of the stove is tightly covered with a cement board. The heat from the stove is dispersed into the mushroom house through the pipe, and the smoke produced is discharged outside the mushroom house through the pipe. In winter, the mushroom house can be heated for cultivation.
2. Three-Bed Type
The mushroom house is 4 m wide and 5 m long, with three rows of bed shelves inside. The left and right rows of bed shelves are 0.7 m wide, and the middle row of bed shelves is 1.2-1.4 m wide, with two walkways, each 0.6 m wide. Other aspects are the same as above.
Straw Mushroom Pile-Straw Cultivation Techniques
Using longer rice straw and wheat straw cut from rice fields, and adopting the traditional pile-straw cultivation method, the cultivation site can be indoors, outdoors in rice fields, in greenhouses, or under fruit trees.
The size of the pile should be determined specifically according to the external temperature. When the temperature is low, the pile shape should be larger; when the temperature is high, the pile shape should be smaller. Generally, when the temperature is about 25°C, the pile width is 75 m and the pile height is about 35 cm; when the temperature is about 30°C, the pile width is 70 cm and the pile height is about 30 cm; when the temperature is above 33°C, the pile width is 60 cm and the pile height is about 25 cm. There are many ways to tread the pile, and the following are mainly introduced:
1. Cut-Straw Style: First prepare the cultivation bed at the cultivation site, level the bed surface, and pour lime water or sprinkle lime powder on the bed surface. To produce more "ground mushrooms," first broadcast a strip of spawn about 1.5 cm wide on the soil around the cultivation bed, then tread the first layer of straw, just covering the spawn. Cut the rice straw soaked in 5% lime water into two sections with a straw cutter, piling while cutting, with the cut ends facing outward and the straw head and tail ends facing inward, one bundle tightly against another, treading firmly with feet, and filling the middle of the pile with loose rice straw, watering appropriately according to the dryness or wetness of the straw. Around the first layer of straw, at about 2 cm from the pile edge, broadcast spawn about 1.5 cm wide facing inward. Then tread the second layer, with the straw bundles just covering the spawn, and the spawning method same as the first layer. Generally, pile 2-4 layers, with each upper layer inset about 2 cm from the lower layer all around, forming a rectangular trapezoid. On the top layer, broadcast spawn, and after spawning cover with a thin layer of rice straw, tread firmly, shape into a turtle-back form, and cover the pile surface with plastic and rice straw. Generally, about 5 bottles of spawn are broadcast for 50 kg of rice straw. Appropriately increasing the spawning rate results in fewer contaminating fungi, faster fruiting, and higher yield.
2. First soak the rice straw in 5% lime water for 5-6 hours, then twist the rice straw into "figure-8" shaped bundles, tie tightly with straw, with each bundle weighing about 0.25 kg dry weight. Other methods are the same as above.
3. Folded-Tail Style: This method is suitable for long rice straw of 65 cm or more, with each bundle weighing about 0.4 kg dry weight. Tie the bundle at about 1/3 from the straw head, requiring the straw heads to be neat. When treading the pile, the straw heads are on one side of the bed and the straw tails on the other side of the bed, while folding and turning the straw tails and treading firmly. After spawning, tread the second layer. The direction of the straw heads is opposite to the first layer, pressing on the straw tails of the first layer. Other methods are the same as above.
Harvesting of Straw Mushrooms
Straw mushrooms take only about 12 days from spawning to the start of harvesting. Straw mushrooms grow quickly and open their caps easily, so timely harvesting must be achieved. The appropriate harvesting time for commercial straw mushrooms is when the mushroom buds have grown to full size and the base wrapper has not yet opened. During the peak production period, harvesting should be done 2-3 times daily. When harvesting, press down on the substrate with one hand and gently twist off the fruiting body with the other hand, being careful not to damage immature young buds. The harvested mushrooms should be promptly trimmed with a sharp knife to remove rotting straw and soil from the base of the fruiting bodies and sent to market for fresh sale in a timely manner. In addition to fresh sale, they can also be processed into dried straw mushrooms or canned straw mushrooms.
After harvesting the first batch (flush) of mushrooms, the second batch (flush) generally appears after 4 days. With proper management, 2-3 flushes can be harvested. However, the first flush is the main one, generally accounting for about 80% of the total yield. Some mushroom houses, in order to improve bed utilization, usually harvest only one flush.
Main Problems and Control Measures in Straw Mushroom Cultivation
1. Causes and Control Measures of Coprinus (Ink Cap) Occurrence
Coprinus atramentarius and Coprinus membranaceus are the most common competitive contaminating fungi in straw mushroom cultivation. They favor high temperature and high humidity and generally appear one week after spawning or after fruiting. Once they occur, they contaminate the substrate surface and consume large amounts of nutrients and water from the substrate, thereby affecting the normal growth and development of straw mushroom mycelium and causing reduced straw mushroom yield. Therefore, controlling the occurrence of Coprinus and how to control it after occurrence is a key technical measure for increasing straw mushroom yield. The causes and control measures of Coprinus occurrence are introduced as follows:
① Poor quality of cultivation raw materials. When cultivating straw mushrooms, using old and moldy raw materials as cultivation substrate makes it prone to pest and disease occurrence. Therefore, during cultivation, raw materials free from mold must be selected, and before use, they should be turned and sun-dried in the sun for 2-3 days, using ultraviolet rays in sunlight to kill contaminating fungal spores.
② Unreasonable substrate formula. The formula and treatment of the cultivation substrate also have a great relationship with the occurrence of Coprinus. Coprinus and similar contaminating fungi have a higher nitrogen requirement than straw mushrooms. Therefore, when preparing the substrate, if too much cow manure or urea is added, reducing the C/N ratio and increasing the ammonia content during substrate piling, it can lead to massive occurrence of Coprinus. Therefore, when adding urea, cow manure, etc. as supplementary nitrogen sources in the substrate, urea should be controlled at about 1%, and cow manure at about 10%, and they should only be used after full fermentation and decomposition.
③ The pH value of the substrate is too low. The pH value of the substrate is also one of the important causes of contaminating fungus occurrence. Straw mushrooms prefer alkaline environments, while contaminating fungi prefer acidic environments. Therefore, when preparing the substrate, appropriately increase lime, generally about 5% of the substrate, to raise the pH value so that the substrate pH reaches 8-9. In addition, after spawning straw mushrooms, immediately sprinkle a thin layer of plant ash on the substrate surface or spray lime water after harvesting mushrooms to adjust the substrate pH value, which can also inhibit the occurrence of Coprinus and other contaminating fungi.
④ Incomplete substrate fermentation. High moisture content of the substrate, insufficient aeration during piling, low fermentation temperature during piling, and failure to loosen the substrate after entering the house, with excessive ammonia in the substrate, can all cause the occurrence of Coprinus. Performing secondary fermentation of the substrate can make the substrate ferment thoroughly, which is an important measure to prevent pest and disease occurrence. It is also a key technique for increasing straw mushroom yield.
In addition, spawn carrying contaminating fungi, excessively high temperature in the cultivation room, and poor ventilation also make pest and disease occurrence more likely. Once Coprinus occurs on the mushroom bed, it should be removed promptly to prevent the spread of Coprinus spores. In addition, during the straw mushroom cultivation process, mycelial shrinkage can also occur, causing massive death of young mushrooms.
2. Causes and Control Measures of Mycelial Shrinkage
Under normal conditions, about 12 hours after spawning, straw mushroom mycelium can be seen germinating and growing into the substrate. If after 24 hours of spawning, mycelium still does not germinate or does not grow into the substrate, or mycelial shrinkage occurs during cultivation, the main reasons are:
① The spawn age of the cultivation spawn is too old. Straw mushroom mycelium grows quickly and also ages quickly. If mycelium does not germinate after spawning and the mycelium in the spawn blocks shrinks, it is often due to too old spawn age or storage under too low temperature conditions. Select spawn of appropriate age; generally, spawn with mycelium that has reached the bottom of the bottle for about one week is best for spawning.
② The substrate temperature is too high. If the substrate is spread too thick, the bed temperature will spontaneously rise. If the temperature inside the substrate exceeds 45°C, it will cause mycelial shrinkage or death. After spawning, closely monitor the indoor temperature and substrate temperature. If the temperature is too high, measures should be taken promptly to cool it down, such as strengthening indoor ventilation, removing the plastic film covering the substrate surface, spraying in the air, loosening the substrate, and pouring water on the ground.
③ The moisture content of the substrate is too high. At spawning, if the substrate moisture content is too high, exceeding 75%, the substrate is not breathable. After spawning, the plastic film is covered too tightly and not lifted for a long time, plus poor ventilation in the mushroom house, causing straw mushroom mycelium to shrink due to oxygen deprivation and suffocation.
④ Ammonia damage in the substrate. Adding too much urea to the substrate, combined with covering with plastic film after spawning, prevents ammonia from volatilizing out of the substrate, causing harm to straw mushroom mycelium.
3. Causes and Control Measures of Massive Death of Young Mushrooms.
During the straw mushroom production process, patches of small mushrooms wilting and dying can often be seen, causing serious losses to straw mushroom yield. There are many reasons for young mushroom death, mainly:
① The substrate is too acidic. Straw mushrooms prefer alkaline environments. When the pH value is less than 6, although mushrooms can form, they are difficult to grow larger. Acidic environments are more suitable for the growth of contaminating fungi such as green mold and yellow mold, competing for nutrients and causing straw mushroom death. Therefore, when preparing the substrate, appropriately increase the pH value in the substrate. After harvesting the first flush, spray 1% lime water or 5% plant ash water to maintain the substrate pH at around 8.
② The substrate temperature is too low or the temperature changes suddenly. Straw mushroom growth is very sensitive to temperature. Generally, when the substrate temperature is below 28°C, straw mushroom growth is affected or even dies. If the temperature changes too much, such as encountering a cold wave or typhoon, causing a sharp drop in temperature, it will cause young mushrooms to die, and in severe cases, large mushrooms will also die.
③ Improper water use. Straw mushrooms have certain requirements for water temperature, generally requiring the water temperature to be similar to room temperature. If deep well water at about 20°C is sprayed in hot summer, it will cause massive death of young mushrooms. Therefore, water spraying should be done in the morning and evening, with the water temperature preferably around 30°C. Correctly master water spraying according to the different stages of straw mushroom fruiting body growth and development. If the fruiting bodies are too small, excessive water spraying will cause young mushrooms to die. During the pinhead stage and small button stage of fruiting bodies, water spraying on the substrate surface must be stopped. If the substrate surface is relatively dry, spraying can only be done in the walkway of the cultivation room, and water can be poured on the ground to increase relative air humidity.
④ Harvesting damage. Straw mushroom mycelium is relatively sparse and extremely easily damaged. If the picking action is too large, it will disturb the surrounding substrate, causing mycelial breakage, and the mycelium of surrounding young mushrooms breaks, so water and nutrients cannot be supplied. Therefore, the picking action should be as gentle as possible. When picking straw mushrooms, press down on the growth base of the mushroom with one hand to protect other young mushrooms, and twist and pick up the mature mushroom with the other hand. If there are densely clustered mushrooms, they can be picked together to avoid causing the death of many immature mushrooms due to the disturbance of individual mushrooms.