Key Management Techniques for Autumn Cropping of Agaricus bisporus (Button Mushroom)

Autumn mushroom management should be based on the environmental requirements for mycelial and fruiting body growth, correctly handle the contradiction between outside temperature and indoor temperature, and flexibly manage bed watering and mushroom house ventilation under natural temperature conditions to meet the requirements for mycelial and fruiting body growth.

1. Mycelial growth in the casing soil layer: After the moisture of the casing soil layer has been adjusted, the stage of mycelial growth management in the soil layer begins. The management principle for this stage is: under the condition of maintaining relatively constant air humidity in the mushroom house (80%-85%) and mushroom house temperature (20-22°C), carry out appropriate ventilation to ensure the mycelium grows fully and well within the soil layer. The specific measures are as follows: (1) Close windows to hang the mycelium. First, the mycelium is required to rapidly grow onto the casing soil layer and extend neatly and vigorously into the soil layer. In terms of management, adopt the method of tightly closing doors and windows and opening roof vents. The mushroom house only needs to open windows for ventilation for about 30 minutes before 6 o'clock and after 20 o'clock to expel waste gas from the mushroom house. In special circumstances, when the mushroom house temperature rises above 25°C, it is necessary to open wind-sheltered doors and windows for ventilation. This stage of management requires 4-5 days. (2) Grow fully and well through the soil layer mycelium. 6-7 days after the moisture adjustment of the casing soil layer is completed, some mycelium begins to emerge on the surface of the casing soil layer. At this time, cover with a layer of soil particles containing a certain amount of moisture, about the size of soybeans. The soil particles should be moistened with water one day before casing, so that the soil particles can be flattened by hand pressure, with a casing thickness of 1 cm. When casing, minimize air movement in the mushroom house, only open one door for entry and exit. Casing is best done after 9 o'clock and before 17 o'clock. After casing, gradually increase ventilation in the mushroom house, half-open the wind-sheltered doors and windows for 1 hour each day, with window opening time after 9 o'clock and before 17 o'clock; ventilation should not be carried out in the morning and evening. The purpose of management at this stage is neither to let the mycelium run upward nor to let the mycelium prematurely twist into primordia, but to let the mycelium grow fully and well within the soil layer, laying a foundation for high yield. This stage of management generally requires 4-5 days, requiring the mycelium to grow horizontally within the soil layer. If the cultivation techniques are excellent, it can be extended by another 2-3 days. In special circumstances, if the temperature is below 19°C, minimize ventilation as much as possible to prevent outside cold air from entering the mushroom house and causing the mycelium to prematurely twist into primordia. At this stage, according to the air humidity and the moisture-retaining conditions of the mushroom house, appropriately maintain air humidity by spraying mist on the mushroom bed, walls, floor, and space.

2. Promoting mushroom formation. Generally, about 12 days after casing and moisture adjustment, the mycelium has grown fully and well within the soil layer, and the mycelium can be prompted to form mushrooms. Specific measures: First, open the doors and windows of the mushroom house in the morning and at night for large ventilation, and half-open wind-sheltered windows during the day. Second, spray water 2 times a day, about 0.9 kg/sq m each time, for 3 consecutive days; never spray heavy water. Through cooling the mushroom house, ventilation, and bed watering, after about two days, the mycelium can twist into primordia, and after another 2-3 days, small mushroom buds can develop. This stage of management generally requires about 5 days. In special circumstances, that is, when the mushroom house temperature is above 19°C, wait until the mushroom house temperature drops below 19°C before carrying out the work to promote mycelial twisting; otherwise, the mycelium in the soil layer will run out of the soil layer or even grow excessively.

3. Promoting fruiting body expansion. When the mycelium has twisted into primordia and grown to the size of soybeans, the fruiting bodies can be promoted to expand. The management principle is: spray a large amount of water on the mushroom bed to ensure relatively constant air humidity in the mushroom house (85%-90%) and relatively constant air flow in the mushroom house. Water spraying standard: however much the first batch of mushrooms on the bed can produce in weight, spray that much water. Under normal circumstances, the amount of water sprayed is about 5.4 kg/sq m, applied in 4 sessions, spraying 2 times a day, about 1.35 kg/sq m each time. Water spraying is best done in the morning and evening when temperatures are lower; before and after spraying, open doors and windows for large ventilation for more than 30 minutes. After ventilation is completed, tightly close doors and windows, but the roof vents must be opened; the air in the mushroom house should be such that people do not feel stuffy. After 2-3 days like this, harvesting can begin. One day before harvest, it is not advisable to spray water again, to prevent affecting the growth of the next batch of mushrooms.

4. Management between flushes. After a batch of mushrooms has been harvested, promptly clean up debris such as broken roots on the bed surface. If mycelium is found exposed on the surface of the soil layer, add some soil. If the bed surface is relatively dry, spray a small amount of water, and at the same time increase ventilation in the mushroom house to expel waste gas and speed up the flush transition. When the fruiting bodies reach the size of soybeans, begin spraying water. The principle of water spraying is: spray according to the mushrooms; spray more when there are many mushrooms, spray less when there are few mushrooms; spray more in the early stage of autumn mushrooms, spray less in the later stage. When young mushrooms emerge and the flush begins, appropriately reduce ventilation and maintain humidity in the mushroom house. Generally, spray mist 1-2 times a day on the mushroom house space, walls, bed surface, floor, and other places.

5. Harvesting. Mushrooms must be harvested at the right time to ensure quality and yield. When the mushroom cap diameter is 2.5-4 cm, they can be harvested. Do not let the fruiting bodies grow too large, otherwise it will shorten the time from harvest to cap opening and also affect the formation and growth of the surrounding next batch of mushrooms. When harvesting, if the mushroom house temperature is above 16°C, the fruiting bodies grow quickly and are prone to thin skin and cap opening, so early harvesting is required, and harvest smaller ones. For the first three batches of autumn mushrooms, the harvest time for each batch is 3-4 days. 6. Reasonable supplementary fertilization. After three batches of autumn mushrooms have been produced, a large amount of nutrients in the compost has been absorbed and utilized by the mushroom mycelium, and the later batches of mushrooms will show phenomena such as reduced number of mushrooms, smaller mushroom shape, and increased thin-skinned mushrooms. Therefore, timely and reasonable supplementary fertilization is needed to increase nutrients in the casing soil layer for mycelial growth and utilization. The commonly used supplementary fertilizers and application methods include the following. (1) Glucose solution: Use 2% oral glucose or white sugar, brown sugar in the fruiting water after the third batch of autumn mushrooms, with relatively obvious effects. However, if the temperature is above 16°C, sugar solution must not be sprayed, to avoid the occurrence of contaminant fungi. (2) Urea solution: Prepare urea into a 0.1%-0.2% solution, and use it on the bed surface when spraying fruiting water. Urea solution should also be applied after the third batch of mushrooms; if used too early, mycelial overgrowth will occur. (3) Triacontanol: Also known as melissyl alcohol. Use a 0.04%-0.016% solution of triacontanol during the mycelial growth period after the third batch of autumn mushrooms; it has a promoting effect on mycelial growth and fruiting body development.