Detailed Guide to Intercropping Oyster Mushrooms in Rice Fields

During the growth and development of rice, intercropping oyster mushrooms using the spaces between rice rows and the special conditions under the shade of rice clumps can provide suitable temperature and humidity conditions for the growth of oyster mushrooms (large temperature difference between day and night, good shading, sufficient scattered light, etc.), enabling high yields of oyster mushrooms, filling the market off-season when few mushrooms are available in summer, enriching summer vegetable varieties, and increasing rice farmers' income.

I. Crop rotation arrangement and field plot design: Rice varieties should be selected with strong lodging resistance, tall plants, thick stalks, and resistance to rice planthoppers. Sowing in late May, transplanting in late June, with a density where a 24 x 45 cm polypropylene plastic mushroom bag can fit between two rice clumps, leaving a walkway of more than 30 cm at intervals of several plants for inspection and mushroom harvesting. Before placing the mushroom bags, the field should have perimeter ditches and furrow ditches dug to facilitate drainage and irrigation.

II. Selection of oyster mushroom varieties: Stock spawn production is generally done in late June, commercial spawn production in late July, and cultivation bag production in late August. High-temperature strains should be selected, such as 831, Sanxia No. 13, HP-1, and Phoenix-tail mushroom (Pleurotus pulmonarius); broad-temperature oyster mushrooms such as Sanxia No. 1 can also be used.

III. Bag making and mycelium running: 1. Substrate formula. Formula 1: cottonseed hulls 89%, corn flour 3%, gypsum powder 2%, imported compound fertilizer 1%, lime powder 5% (mixed with water). Formula 2: rice straw 79%, wheat bran 10%, corn flour 3%, compound fertilizer 1%, gypsum powder 2%, lime 5% (mixed with water). To both formulas above, add 0.2% carbendazim, with a moisture content of 62-65%. Each bag holds 1-1.2 kg of dry material.

2. Pile fermentation. Select fresh, mold-free cottonseed hulls or golden-colored rice straw and sun-dry for 2 days to kill unwanted microorganisms and pests, then mix the ingredients in the above formula evenly, mix with lime water, at a material-to-water ratio of 1:1.6. Then make a pile 1.5 m wide, 1.2 m high, and of unlimited length. Cover the surroundings with plastic film, and the top with rice straw. In rainy weather, cover with plastic film to prevent rainwater from entering the pile. After 2-3 days, turn the pile once to exchange the top, bottom, inner, and outer positions of the material. Pile for another 2-3 days, still keeping it covered.

3. Bag filling and inoculation. Before bag filling, spray the pile and the site evenly with 1:1000 dichlorvos and 1:100 cresol soap solution to further kill pests, remove ammonia odor, and disinfect the site environment. When filling bags, pack the material tightly, leaving 5 cm at each end of the bag, then use a 2-2.5 cm diameter wooden stick to make a hole through the center of the material from end to end, fill the hole with spawn, sow a layer of spawn on the material surface at both ends, put on collar rings, cover with two layers of kraft paper, tie securely with string, and place in a cool room for mycelium running. During mycelium running, frequently check the material temperature changes and mycelial growth; remove contaminated bags promptly, pay attention to ventilation and bag turning; mycelium can fully colonize in about 20 days.

IV. Management after mushroom bags are placed in the field: After the mycelium has grown well and fully, which coincides with the completion of rice canopy closure and heading, providing shade and insulation conditions, move the colonized bags into the rice field for the fruiting stage management. Before moving the bags into the rice field: first, dig the perimeter ditches and furrow ditches well and drain standing water (moisture management thereafter); second, treat once heavily for rice planthoppers; third, remove the collar rings from the bags and roll the bag openings down to the level of the substrate; fourth, after the bags are placed, irrigate with a large amount of water, flooding no more than 1/3 of the bag height, drain after 3-5 hours, then promote primordium formation. Later water management follows the principle of frequent irrigation and frequent drainage. Using an alternating wet-dry management method, the first flush of mushrooms can be harvested after 1 week. After harvesting the first flush, irrigate again with a large amount of water, drain after 24 hours, and enter the management for the second flush; the second flush can be harvested in about 10 days. In this way, a total of 3-4 flushes can be harvested until rice harvest. If the bags can still produce mushrooms, they can be moved to other sites and buried in soil for further fruiting, or used to cultivate shaggy mane mushrooms (Coprinus comatus).

Generally, 4000 bags can be placed per mu of rice field, and more than 6000 kg of fresh oyster mushrooms can be produced per mu. (Yang Dalin)