How to Grow Agaricus bisporus Well? A Full Analysis of the Key Cultivation Techniques
How to grow Agaricus bisporus well? An introduction to Agaricus bisporus, also known as the button mushroom or cultivated mushroom, the world's largest edible fungus by volume. Its nutritional value is extremely high, and it is currently developing very rapidly, growing at 15%-20% per year. Agaricus bisporus is a straw-decay fungus, a medium-to-low temperature mushroom; in northern regions, rice straw and wheat...
How to grow Agaricus bisporus well? An introduction
Agaricus bisporus, also known as the button mushroom or cultivated mushroom, is the world's largest edible fungus by volume. Its nutritional value is extremely high, and it is currently developing very rapidly, growing at 15%-20% per year. Agaricus bisporus is a straw-decay fungus and a medium-to-low temperature mushroom. In northern regions, rice straw and wheat straw are abundant, and the climate is relatively suitable for the growth of Agaricus bisporus, giving it great development potential.
I. Biological Characteristics
1. Nutrition: Agaricus bisporus is a saprophytic fungus and cannot carry out photosynthesis. When preparing the substrate, an appropriate amount of manure (such as cow, sheep, horse, pig, chicken and human manure/urine) must be added to the crop straw (wheat straw, rice straw), along with appropriate amounts of nitrogen, phosphorus, potassium, calcium, sulfur and other elements. A reasonable formula is an important factor in achieving high yields.
2. Temperature: The mycelial growth temperature range of Agaricus bisporus is 4-32°C, with an optimum of 22-25°C; the fruiting body growth temperature range is 5-25°C, with an optimum of 14-16°C.
3. Humidity: The most suitable water content of the compost is about 60%, and the water content of the casing soil is preferably 16%-20%. During the mycelial growth stage, the relative air humidity is 60%-70%; during the fruiting body growth stage, 85%-90% is preferable. Both excessive dryness and excessive moisture are unfavorable to mycelial growth.
4. pH: Agaricus bisporus prefers slightly alkaline conditions; acidity is unfavorable to both mycelial and fruiting body growth and easily breeds contaminant fungi. The pH range for mycelial growth is 5-8, with an optimum of 7.0-8.0. Before entering the shed, the pH of the compost should be adjusted to 7.5-8.0, and the pH of the soil particles should be 8-8.5. When watering after each mushroom flush, add a little lime to maintain a relatively high pH and inhibit the growth of contaminant fungi.
5. Air: Agaricus bisporus is an aerobic fungus, so good ventilation conditions are required.
6. Light: Neither the mycelium nor the fruiting bodies of Agaricus bisporus require light, but they can still grow under general scattered light; strong light exposure is not acceptable. In a dark environment, the fruiting bodies grow white and plump; if the light is too strong, the surface of the fruiting bodies hardens, many deformed mushrooms appear, and their commercial value is poor. Properly arranging the production season is an important prerequisite for achieving high yields; the cultivation time should be determined according to natural temperatures. In the Shandong region, fermentation of the compost should generally begin from August to mid-September. If too early, the temperature is too high; after the end of September, the temperature is too low.
II. Formulas
1. Wheat straw (rice straw) 1500 kg, dry cow (horse) manure 1500 kg, urea 20 kg, soybean cake 50 kg, superphosphate 30 kg, gypsum powder 40 kg, calcium carbonate 30 kg, ammonium sulfate 15 kg.
2. Wheat straw (rice straw) 2250 kg, dry chicken manure 750 kg, urea 17.5 kg, cake fertilizer 75 kg, superphosphate 25 kg, calcium carbonate 40 kg, ammonium sulfate 15 kg. The above amounts are for 100 sq m of substrate, and the pH of the compost is adjusted to 8 in each case.
III. Stacking and Fermentation of the Compost
The compost generally undergoes secondary fermentation, also called pre-fermentation and post-fermentation. Pre-fermentation is carried out outside the shed, and post-fermentation is carried out inside a disinfected shed. Pre-fermentation takes about 20 days, and post-fermentation takes about 5 days. The whole process takes about 22-28 days.
1. Pre-wetting the compost (wheat straw, rice straw)
If conditions permit, soak for 1-2 days, then remove and drain off excess water, and build the stack directly as required. When soaking, add an appropriate amount of lime powder to the water; add 15 kg of lime powder per cubic meter of water. Generally, when soaking wheat straw (rice straw), growers first dig a pit, the size of which depends on the planting quantity, line the pit with a plastic film, pump in water, and add lime powder. Build the stack while removing the straw from the water. After the stack is built, water the top of the stack every day, using the standard that water overflows from the bottom of the stack; in 3-4 days the wheat straw has basically absorbed enough water.
2. Building the stack: The compost stack should be 2 m wide and 1.5 m high; the length can be determined according to the planting quantity. When building the stack, drive a wooden pole about 10 cm in diameter and more than 1.5 cm long vertically every one meter; after the stack is built, pull the poles out, naturally forming an air hole to increase oxygen inside the compost and facilitate microbial reproduction and even fermentation. When stacking, first spread a layer of wheat straw (about 25 cm thick), then a layer of manure, tamping it down as you go; the manure should be spread evenly. Following this method, stack layer after layer of straw and manure up to a height of 1.5 m, then cover the top with manure. Sprinkle 1/2 of the urea evenly in the middle of the stack. Water each layer during stacking; the bottom layers should be watered less and the upper layers more, so that water overflows around the stack the next day. When building the stack, note that the four sides should be as steep and straight as possible, and the width at the bottom and top of the stack should differ little, so that the temperature inside the stack can be maintained well. The stack must not be built into a triangle or a nearly triangular trapezoid, because this is unfavorable for heat preservation.
3. Turning the stack (fermentation): When turning the stack, the innermost and outermost layers of the compost should be turned to the middle, and the middle compost turned to the inside and outside layers. Each time the stack is turned, the chemical fertilizers and other auxiliary materials that should be added are added in the required order. If the compost is too dry, water it appropriately. If sunny weather occurs after each stacking, use straw curtains or corn stalks for shade; on rainy days, cover with plastic film to prevent rain, and remove the plastic film after the weather clears. Under normal conditions, the stack begins to heat up on the second day after building, and after about the 3rd day the compost temperature rises above 70°C; after about another 2 days the compost temperature begins to fall, at which point the first turning is carried out, sprinkling in the remaining urea along with calcium carbonate, gypsum powder and phosphate fertilizer while turning, spreading them evenly. After rebuilding the stack, wait until the compost temperature rises above 70°C, hold for 2 days, then carry out the second turning. The method for each turning is the same; ammonium sulfate is added at the second turning, and generally the stack is turned 3 times. Check the pH of the compost at each turning; if it is acidic, sprinkle in an appropriate amount of lime powder along with watering, keeping the pH at about 8. Well-fermented compost is light coffee-colored, has no foul or ammonia smell, is soft in texture, has lost its toughness, but is elastic.
4. Post-fermentation (also called second fermentation): Move the fermented compost into the shed while hot, pile it into small heaps, each heap being just enough to spread over one bed surface. When the compost temperature rises to 60°C, hold for 6 hours to further kill contaminant fungi and pests. Then let the compost temperature fall to 52°C and hold for 4 days to promote the growth and reproduction of microorganisms, ventilating twice a day for 15 minutes each time. If the compost is on the dry side, spray lime water according to the pH of the compost. After that, begin spreading the compost to a thickness of 25-30 cm, patting it down gently while spreading. Well post-fermented compost should be brownish-red, with a large amount of white powdery actinomycetes, a sweet bread smell, and a water content of about 60%-62%. When grasped in the hand, water marks appear between the fingers; it can be held into a ball and breaks apart when shaken, with a pH of about 7.5.
IV. Cultivation Management
1. Spawning: Begin spawning when the temperature drops below 27°C. Broadcast spawning is generally used, spreading
3/4 of the spawn evenly over the surface of the compost, then insert a small fork halfway into the compost thickness and shake gently so that the spawn is evenly distributed into the compost, then spread the remaining 1/4 of the spawn evenly over the surface of the compost. After spawning, cover with a layer of newspaper; if the temperature inside the shed is relatively high and its insulation performance is good, the newspaper may be omitted.
2. Mycelial running: From spawning to casing is the mycelial running stage. During this period the temperature should be controlled at 20-25°C, and the relative air humidity kept at about 70%. For 1-2 days after spawning, generally keep the shed closed without ventilation, focusing on heat and moisture retention. After about 3 days the mycelium begins to germinate, and at this point ventilation should be strengthened so that the mycelium on the surface grows into the compost. When the mushroom shed is dry, sprinkle water into the air, onto the walls and along the walkways to increase air humidity.
3. Treatment of casing material: Ideal casing materials are generally paddy field soil, pond soil, wheat field soil, bean field soil, yellow soil, river mud, etc. Vegetable garden soil is generally not used, because its high nitrogen content easily causes excessive vegetative growth of the mycelium, resulting in few mushrooms, and it easily harbors large numbers of pathogens and insect eggs. The soil should be taken from below 15 cm of the surface, exposed to the hot sun, and preferably granular, with small particles 0.5-0.8 cm and clods 1.5-2.0 cm; then mix in 1% lime powder, spray with formaldehyde and 0.05% dichlorvos, pile it up, cover with plastic film and fumigate for 1 day, then remove the film, spread the pile out until the chemical smell has dissipated, and it is ready for casing.
4. Casing: After about 15 days, when the mycelium has basically covered 2/3 of the compost, casing should be done in good time. After casing, spend 3 days watering so that the soil fully absorbs water, but the water must not seep into the compost; when watering, be frequent, gentle and light. The thickness of the casing layer is 25-30 cm.
5. Fruiting management: About 20 days after casing, mushrooms begin to appear. Keep the temperature at 20-24°C and the relative air humidity at 80%-85%. During this period, generally do not spray water on the compost surface; if too wet, aeration is poor and the mycelium struggles to penetrate the soil layer; if too dry, the mycelium is sparse. Maintain suitable temperature and humidity, and the mycelium will quickly grow white and vigorous. When the mycelium covers the compost surface, spray heavy water to make the mycelium lie down; this watering is also called "fruiting water," to stimulate the formation of fruiting bodies. After that, stop watering for 2-3 days while increasing ventilation. When the mycelium twists into small white dots, begin watering and increase humidity. Keep the relative air humidity at about 90% and control the temperature at 12-18°C. As the number of mushrooms increases and the fruiting bodies develop, increase the amount of watering; strengthen ventilation when watering; do not water at high temperatures; and do not water before harvesting.
When the mushrooms grow to the size of a soybean, spray 1-2 heavier rounds of "fruiting water," once a day, to promote the growth of young mushrooms. After that, stop watering for 2 days, then gradually reduce the amount of watering as the mushrooms grow, continuing until the peak flush is about to begin, and then gradually reduce the amount of watering as the mushrooms are harvested. Note that watering should be frequent, light and fine; water less on cloudy days and not at all on rainy days. During the fruiting stage, harvest every day, picking according to the size the market requires, but the caps must not open; when harvesting, twist gently and try not to pull out compost. Trim off the muddy base of the stem as you pick, to avoid reducing commercial value. Handle gently; bruised areas discolor very easily. After each flush is harvested, clean the compost surface, fill the hollows left by picked mushrooms with soil, and keep the surface level and clean. After this is done, spray once more with 1% lime water, then follow routine management; after about 7-10 days the second batch of mushrooms appears. Generally 6-9 flushes are harvested. After the 3rd flush, loosen the soil layer and make holes to improve aeration within the compost, and after harvesting and before new pins grow to the size of a bean, spray fertilizer.
V. Treatment of the Plastic Shed
Before the post-fermented compost enters the shed, the shed must undergo a thorough disinfection and pest-killing. Irrigate once with water and ventilate to reduce moisture. When the ground is no longer sticky, spread quicklime powder evenly over the ground at 0.25 kg per sq m, hoe it in, and spray pesticide 1605 or dichlorvos. Three days before the compost enters, disinfect again with 10 ml of formaldehyde per cubic meter. Ventilate before the compost enters to ensure fresh air in the shed and facilitate operations.
VI. Problems in Cultivation and Countermeasures
1. Management after spawning: If the mycelium grows poorly after spawning, the spawn does not germinate, does not colonize the compost, grows only on the surface, or shrinks, find the cause promptly and take remedial measures. When the compost has an ammonia smell, poke holes in it and strengthen ventilation. If the compost is on the dry side, spray water on the covering newspaper twice a day. If the compost is too wet, strengthen ventilation; in high temperatures, take cooling measures; if the cause is the spawn, replace the spawn promptly and re-spawn.
2. Poor mycelial growth after casing: If 3-5 days after casing the mycelium does not climb onto the soil and appears grayish-white, sparse and weak, or in severe cases no mycelium is visible on the compost surface or it even turns black, this is caused by mycelial shrinkage. The main cause is excessive or too rapid watering after casing, causing oxygen deprivation and suffocation and shrinkage of the mycelium. Stop watering immediately, strengthen ventilation, and reduce the moisture of the compost to help the mycelium recover and climb onto the soil.
If the casing material is on the dry side, has a pH below 5, or has a high salt content, the mycelium tends to grow abnormally within the compost and is slow to climb onto the soil. If the mycelium grows out of the surface of the soil layer and persists for 2-3 days in a high-temperature, high-humidity environment, it will grow excessively, forming a dense mycelial mat that is impermeable to water and air. The measures to prevent excessive mycelial growth and mat formation are: as soon as the mycelium just grows out of the casing layer, strengthen ventilation in good time to dry the soil surface, prompting the mycelium to shift from vegetative growth to reproductive growth, and spray fruiting water promptly to favor the formation of primordia. If strengthening ventilation still cannot make the mycelium lie down, spray 0.5% lime water. If a mycelial mat has already formed on the soil surface, use a small knife or bamboo strip to lift and discard the mat.
3. Rust spots: After the fruiting bodies emerge, if ventilation is not carried out promptly after watering, the high air humidity slows the evaporation of water from the mushroom surface, and rust-colored spots appear where water droplets collect on the caps. Although the spots do not grow into the flesh, they reduce mushroom quality.
4. Hollow mushrooms: During the fruiting period, if the temperature is high, the fruiting bodies grow rapidly and the water supply is insufficient, white loose pith forms in the stipe, and the stipe may even become hollow. Sometimes, because the temperature is low and the fruiting bodies grow slowly, staying too long on the bed surface also forms hollow mushrooms. Adjust the water content of the casing promptly and carry out appropriate intermittent heavy watering. Also pay attention to temperature regulation.
5. Hard opening
When the temperature fluctuates greatly, with a day-night temperature difference of more than 10°C, combined with low air humidity and excessive ventilation, immature fruiting bodies that are still growing easily open their caps or develop cracks. A casing layer that is too thin can also cause hard opening.
6. Clustered mushrooms: Many fruiting bodies of uneven size densely clustered together not only fail to increase yield but also waste nutrients and make harvesting inconvenient. The occurrence of clustered mushrooms is related to the characteristics of the spawn and the spawning method; generally, aged spawn and the hole-spawning method easily produce clustered mushrooms. A mixed spawning method can be used, or before casing, dig out the old spawn blocks from hole spawning and fill level with compost.
7. Preventing and controlling red-root mushrooms: During the high-temperature stage before fruiting, using too much water, or acidic compost, or too much glucose, or poor ventilation, easily produces red-root mushrooms. Keeping the casing water content at 22%-25%, avoiding watering at high temperatures, applying topdressing properly, and spraying some clear lime water can prevent red-root mushrooms.
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