Analysis of the Reasons for the High Economic Returns of Winter Cultivation of Straw Mushrooms
Straw mushrooms (Volvariella volvacea) are a type of fungus that thrives in high temperature and high humidity, suited to growing in an environment of constant temperature and stable moisture. Therefore, moving the heat-loving straw mushroom to winter cultivation requires growing it in greenhouses with good insulation capacity, which increases cost inputs such as heating. However, straw mushrooms produced in winter sell for 2 times the price of those conventionally cultivated in summer, so appropriate adjustments should be made to the substrate formula and cultivation management, among other aspects, in order to increase the input-output ratio and improve economic returns. The main techniques for winter cultivation of straw mushrooms are introduced as follows:
1. Select a suitable substrate formula, build a pile and ferment
Off-season cultivation of straw mushrooms cannot use a single straw formula with few nutrients and low yield; instead, a formula rich in nutrients and with high biological efficiency should be selected. In production, the following are mostly used: cottonseed hulls 68%, rice straw 20%, urea 1%, lime 6%, calcium carbonate 3%, plant ash 2%; or waste cotton 77%, rice straw 10%, wheat bran 5%, lime 8%. Using the secondary fermentation method, first sun-dry the cottonseed hulls for 3 to 4 days, adjust with lime water until the substrate moisture content is 70% to 75% and the pH value is 7 to 8, pile outdoors for 3 days, then move the substrate indoors, keep the substrate temperature at 70°C for 10 hours and it is ready.
2. Management before sowing and fruiting
After the substrate fermentation is finished, adjust the moisture content to 65% and the pH value to about 9. When the substrate temperature drops to 35°C, it can be sown. A strip-laying broadcast sowing method can be used, that is, divide an 80 cm wide bed into 5 equal parts, each strip 16 cm wide, fill the middle strip with fertile soil, and fill the two sides with substrate, with a substrate amount of 10 kg per sq m. After the substrate is laid, press it lightly, scatter the spawn on the substrate surface with a sowing amount of 4% to 6% of the substrate weight, then scatter a layer of substrate over the spawn, and apply 5 to 6 cm of fertile soil along the outer sides of the two substrate strips. Close the mushroom shed so that the shed temperature reaches 30°C to 35°C, and do not open doors or windows for 3 days to maintain high temperature and high humidity, so as to facilitate mycelial sprouting. Afterward, ventilate and exchange air for about 20 to 30 minutes each day. After 4 to 5 days, when the mycelium has colonized 2/3 of the substrate, a small amount of water can be sprayed to encourage the mycelium to colonize the substrate thoroughly. After 6 days, when the mycelium has grown through the substrate, water should be adjusted appropriately to a sufficient level, and ventilation, air exchange and light transmission should be strengthened to promote fruiting body formation. After 8 days, the mycelium begins to knot and mushroom buds appear. At this time, the substrate surface should be appropriately dried to increase mushroom formation and reduce dead mushrooms.
3. Strengthen management during the fruiting period and harvest in time
About 10 days after sowing, dense small white dot-shaped mushroom buds can be seen appearing and gradually growing larger, and the first flush of mushrooms can be harvested in 13 to 15 days. The yield of the first flush accounts for 60% to 70% of the total yield. Management of temperature, humidity, air and light should be strengthened. When the mushroom buds form, strengthen ventilation to expel waste gas and regulate room temperature; keep the room temperature at 32°C to 34°C, keep the relative air humidity at 85% to 90%, reduce the amount of water sprayed, and increase the frequency of spraying. After each flush is harvested, promptly clean the substrate surface; on the premise of keeping the mushroom house temperature basically stable, spray water to retain moisture, adjust the pH value to slightly alkaline, and promote mycelial recovery. While replenishing water, some nutrient solution such as 0.1% urea can also be applied to promote the differentiation and development of fruiting bodies. After 7 days, the second flush of mushrooms can be harvested. If harvesting two flushes is the goal, one production cycle takes about 20 days or so.
Straw mushrooms grow extremely fast and often open their caps overnight, so they should be harvested in time. When the straw mushroom changes from a pagoda shape with a relatively wide base and a slightly pointed top to an oval shape, when the mushroom texture changes from firm to soft, when the color changes from dark to light, and when the wrapper membrane has not ruptured and the cap and stipe have not extended out, it is the most suitable time to harvest. Generally, harvest once each in the morning, midday and evening. Freshly picked mushrooms should promptly have the soil on the surface of the mushroom base trimmed off with a knife, and they can then be sold or processed.