Detailed Explanation of Key Techniques for Open-Field Cultivation of Shiitake Mushrooms

Open-Field Cultivation Techniques for Shiitake Mushrooms

I. Site Selection and Land Preparation:

1. Site selection. In principle, choose sandy loam plots that are not sticky, not prone to waterlogging, and not drought-prone, for ease of management. East-west oriented ridges are preferable.

2. Land preparation. Prepare the land in autumn, dig out and rake clean the stubble of the previous crop, and make trenches 60 cm wide and 10-15 cm deep, with the trench bottom concave in the middle and lower on both sides, shaped like a turtle's back. From March 15 to April 15 of the following year, plant the shiitake mushrooms into the ground.

II. Pre-Sowing Preparation:

1. Preparation of third-generation spawn and culture material. For third-generation spawn (production spawn), generally 18-20 bottles are needed per square meter. The formula for the culture material is: sawdust 78%, wheat bran 10%, rice bran 10%, gypsum 1.5%-2.0%, plus carbendazim 0.1%, with wood shavings or rice hulls not exceeding 5%. Mix evenly until the moisture content of the culture material reaches 60%. For steaming sterilization, steam in an upper steamer pot, and when the temperature reaches above 97°C, steam for 2 hours and then remove from the pot, put into sterilized woven bags, tie the openings, and place indoors to cool to 20-30°C before sowing.

2. Preparation of straw curtains and frame poles. Open-field shiitake mushrooms require straw curtains to build shade sheds. Straw curtains can be made from various stalks, rice straw, tree branches, etc., 85-100 cm wide, with no limit on length. For frame poles, use various tree branches, 1-1.2 m long.

3. Preparation of other materials. Choose ordinary polyethylene film 0.01-0.014 mm thick and 1.5 m wide. Make inoculation frames from wooden boards 8 cm wide (no limit on length). Prepare quicklime at 200 g per square meter. In addition, prepare 50-55 cm long corn stalks or rice straw bundles, and disinfect them with 1‰ carbendazim water before sowing for later use.

III. Sowing:

First, dig the spawn out of the bottles (bags), remove the old skin, and break into small pieces. First mix 2/3 of the spawn evenly into the cooled culture material, sow into the inoculation frame lined with plastic, and after filling, spread it into a turtle-back shape with hands or a wooden board. Then evenly sprinkle the remaining 1/3 of the spawn on the surface of the material, and pat the surface firm with a wooden board. Place a disinfected corn stalk or rice straw bundle horizontally every 15-20 cm, place one longitudinally through the middle, then fold back the remaining plastic film at the edges, tuck both sides well so the culture material is not exposed, and then cover with 10-15 m of field soil.

IV. Post-Sowing Management:

The growth and development of shiitake mushrooms require nutrients, temperature, moisture, air, light, and suitable pH. After sowing, frequently check whether there are places where the plastic film is exposed, and cover with soil promptly; where the soil cover is thin, add thicker soil cover, to prevent high temperatures from scalding the surface mycelium and causing contamination by foreign fungi.

1. Management during the mycelial stage. About 1 week after sowing, observe mycelial growth at fixed points and regular intervals, monitor temperature and moisture changes in the material, ventilate promptly, and prevent direct light exposure.

2. Management during the color-turning stage. When the mycelium on the surface of the material is uniformly white above and below, it indicates the mycelium has fully colonized the culture material; at this time, remove the soil. After the soil is removed, color turning begins after a period of time. During the color-turning stage, first build the shade shed well and cover with straw curtains. Second, ventilate to promote color turning, maintain temperature, prevent moisture loss, and promptly drain accumulated water on the surface of the material.

3. Management during the fruiting stage. Generally, sowing is done in early April, and "signal mushrooms" can be seen in late August. During this period, adjust the shade shed well, control air temperature and moisture, strengthen ventilation, reduce invasion by foreign fungi, and prevent drought in autumn.

The suitable temperature range during the fruiting stage is 5-25°C, with the optimum being 12-20°C; a day-night temperature difference of 5-10°C is best; humidity 60%; light should be diffused light. During this period, if air is insufficient, deformed mushrooms and small old mushrooms are likely to appear, which can be remedied by adjusting the height of the straw curtains.

4. Management during the overwintering stage. Before the ground freezes, spread tree leaves or stalks flat on the surface of the material, then cover the plastic film that originally wrapped the culture material with soil. Prevent excessive snowmelt water in winter. If water accumulates on the surface of the culture material for too long, the mycelium will suffocate due to lack of oxygen.

V. Harvesting:

??? Harvest when the shiitake mushrooms grow to the point where the caps are about to open. After harvesting, sun-dry or oven-dry them.