Key Technical Points for Mushroom Cultivation and Management in Winter Fallow Fields

Using winter fallow fields to cultivate mushrooms with rice straw and manure as the main raw materials can greatly increase income, and the spent substrate after cultivation can be returned directly to the field or used as raw material for bio-organic fertilizer. The winter fallow field mushroom cultivation technique is introduced as follows:

Substrate formula: when stacking materials, calculated per square meter of mushroom bed, use 12.5-13.5 kg of dry rice straw, 0.8 kg of rapeseed cake powder, 0.45 kg of gypsum powder, 0.45 kg of superphosphate, 0.45 kg of compound fertilizer, and 0.45 kg of lime powder. The raw materials required per mu can be calculated based on a single-layer cultivation area of 390-400 sq m per mu of winter fallow field.

Stacking process: raw materials enter the stacking yard -> dry rice straw soaked and pre-wetted in water for 12-18 hours -> build the stack and lay the straw (stack width 2.5 m, top height 1.5-1.6 m, side height 1.2-1.3 m) -> build the stack vertically layer by layer. Lime is added during the first turning, and auxiliary materials such as rapeseed cake are added layer by layer during stacking. Water adjustment starts from the third layer, splashing and pouring into the stack layer by layer. After stacking, turn the stack every 5 days and control the stack moisture well. The standard for a well-stacked high-quality substrate is: the straw still retains its original shape, is yellow-brown or brown, not very tough, with no severe ammonia odor or other putrid odors, moisture content 60-65%, and when grasped by hand it does not form a ball and no water drips out, but the palm retains a moist mark.

Bed preparation and shed construction: after the late rice harvest, promptly prepare the field and make cultivation beds. The effective mushroom cultivation area per mu is generally 390-400 sq m. Generally, arched shed style and single-layer cultivation beds are used, with a shed height of 1.7-1.8 m, width of 4 m, and length of 10-15 m. First make a cultivation bed 1.6 m wide in the center of the shed, leave a 40 cm wide and 25 cm deep operation path on each side of the central cultivation bed, then make a 60 cm wide cultivation bed on the other side of each operation path, leaving a 20 cm gap at each side of the shed. To make full use of space, a one-and-a-half-layer cultivation bed can be used, with a shed height above 2.1 m, the upper cultivation bed 1.5 m from the shed top, and a 60 cm spacing between the upper and lower cultivation beds. The arched shed covering method can adopt a "sandwich" style, that is, a straw curtain in the middle, with one layer of film on each side, inside and outside.

Laying the substrate: the substrate should be laid evenly in thickness, about 20-25 cm thick, and the substrate moisture content should be controlled at 60-65%.

Sowing: when the substrate temperature drops to about 28°C, sow promptly, with each bottle of wheat grain or millet grain spawn (0.5 kg) sown over an area of 8 sq ft. When sowing, scoop the spawn out of the bottle and break it up, evenly broadcast it on the substrate surface or into the gaps in the substrate, then use a clean wooden board to press and level the substrate surface so as to facilitate contact between the spawn and the substrate.

Spawn run management: 1-3 days after sowing, focus on moisture retention and ventilation management, with the temperature controlled below 28°C, to promote the spawn to germinate as quickly as possible; 3-7 days after sowing, when the spawn has basically germinated and begun to colonize the substrate, ventilate less while still exchanging air; 7-11 days after sowing, when the spawn has begun to colonize laterally, the ventilation volume should be gradually increased to promote robust growth of the spawn within the substrate; 10-15 days after sowing, when the spawn has grown more than 1/2 of the depth within the substrate layer, apply casing soil.

Casing soil: choose fields where mushroom cultivation spent substrate has not been applied that year, take soil below the plow layer, and break it into clods 1-1.5 cm in diameter. Generally, loam or sandy loam that is moist but not sticky, dry but not crumbly, loose and breathable, with strong water retention, a certain level of fertility, and a pH value of about 7.2 is selected as the casing soil. Before casing, apply pesticide to remove miscellaneous fungi and pests in the soil, and spray the substrate surface once with 1:1 equal-amount Bordeaux mixture at 500-800 times dilution. After casing, adopt the method of light spraying and frequent spraying to gradually adjust to the required moisture.

Fruiting management: 12 days after casing, when mycelium can be seen in the soil cracks, promptly spray mushroom-setting water to promote mycelial knotting, with the spray amount 2-3 times the usual amount, subject to the soil layer absorbing enough water without leaking onto the substrate. When spraying mushroom-setting water, the ventilation volume must be 3-4 times greater than usual. When the shed temperature is above 22°C, the spray amount should be appropriately reduced, ventilation increased, and the spraying of mushroom-setting water delayed. When mushroom buds the size of soybeans appear in the soil cracks, promptly spray fruiting water to promote fruiting body formation.