'Cultivation of high-temp. strain', 'ground method', and 'summer cultivation' have close relation with each other. It's because, in summer, the season when mushroom production decreases, growers choose high temp. strains that survive at high temp. and ground method that keeps lower temperature than shelf.
1. 'Ground' method
Bags are prepared during January - February when it is still cold around 5'C. Substrate formula is 79% sawdust, 20% wheat bran, 1% supplements such as gypsum, and water. According to Qingyuan mushroom experiment station, broad-leaf trees can be used for shiitake cultivation are 9 family, 8 genus, 300 species, including Castania henryi, Caslanopsis eyrei, Castanopsis fargesii, Elaeocarpus iaponica, Cyclibalnopsis multinervis, Quercus glanduliferavar brerlpetiolata, Lithocarpus hancei, Liguidambar formosana. But practically, dwellers cut down the trees from near mountainous area illegally. They make smaller-particle sawdust in winter, and chip-like sawdust in summer. Smaller particles are preferred for high temperature strain because it is incubated during cold season. Bags are 2kg at first, loose weight to 1.5kg after browning. During bag preparation, neighbors gather at one grower's and work together. Saying the sterilizer can treat 2,000 bags at one time, they make 2,000 bags daily and repeat it several times. They mix the substrate 3 times with shovel. The sawdust is a mixture of several tree species and the mixing is not complete, therefore, mushroom production is fluctuated by bags.
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| Fig 1. Bag filling with substrate |
Sterilization is performed under normal pressure; it takes over 12 hours to raise the temperature up to 98'C. Tree branches and spent substrates are used as firewood. In order not to collapse the substrate stack during sterilization, they put several bags into larger bags before stacking or bind bags together. After cooling, they place spawning tools and several bags into spawning bench and disinfect the surface by formalin fumigation. Now, they intend not to use formalin fumigation because they know that it can be harmful to human.
Four hole inoculation. With bigger spawning holes, though more spawn spent, faster incubation and less contamination can be expected.
Mushroom mycelia generate heat during incubation. If it is relatively warmer outside, therefore, incubate the inoculated bags in crib stack. But, the temperature is low as 5'C, stack the bags in bulk; and later, when the substrates' temp. increases, restack them into crib shape.
Breathing holes are punched as concentric circles at three times according to mycelial colonization.
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| Fig 2. Fixing the bags before sterilization |
Fig 3. Putting several bags into larger bags |
Incubation completes around late May; then, peel the plastic bag covers and move the incubated bags into growing house. Growing house has no wall; has only plastic sheet and sunblind covered on the roof. Lay the bags on 30cm hills and fill the soil about 2/3 high. Humidity is kept by water flow between the hills.
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| Fig 4. Ground method |
Pinning is induced by watering or sweeping with broomstick on the surface. Summer temperature is 26-27'C at high land. Harvest till late September; 700-800g can be harvested per bag. Peeled bags are sent to reproduction factory, spent substrates are used as firewood for shiitake drying or as fertilizer for other crops.
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| Fig 5. Mushroom dryer using spent substrate |
Fig 6. Spent substrate used as fertilizer |
2. Features
- Even high temperature strains do not bear at over 30'C; therefore, high temperature strains are cultivated in summer at high land.
- Being not so resistant to contamination, bags are made during Jan. - Feb. when it is still cold. But, incubation is very slow at that season; earnest incubation is done at around 20'C. Therefore, it is thought that, if high resistant and short incubation period strains are developed, bags can be made as late as March to April.
- Because it grows fast (high temperature season) in high humidity (ground method) environment, the mushroom quality is low. And huagu is not produced. It has long stipe and dark-colored cap. But the production is originally low in summer season; low quality shiitakes also can be sold and exported.
- 5,000 bags are suitable for 2-person labor. Harvest will be too busy with 10,000 bags. In that case, by burying each 5,000 bags at the interval of two weeks after incubation, they can harvest mushrooms in turn.
- Circulation usually has 3-4 steps. Not having guild, growers take their mushrooms to farmers' market to sell them to exporters or first wholesalers. Some high quality mushrooms can be sorted for gift. There are also wholesale and retail markets. Only dried shiitake is circulated in domestic market of China; salted or frozen shiitakes are also available for export.
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| Fig 7. Farmers' market (fresh shiitake) |
Fig 8. Qingyuan shiitake wholesale market (dried) |
3. Economy
- Growing house
plastic sheet (16 yuan/kg, USD1.93)
sunblind (8.6 yuan/kg, USD1.04)
- Substrate bag
plastic bag (0.12 yuan/bag, USD0.01)
spawn (1.5 yuan/bag, USD0.18); each spawn bag for spawning 40-50 substrate bags
wheat bran (50 yuan/40kg, USD6.04)
Sawudst is, so far, free becuase they cut the trees and make sawdust by themselves
- Shiitake price: 2-6 yuan/kg, USD0.24-0.72
Saying Mr. Lentinula is going to make 5,000 bags,
- Cost
5,000 bags (600 yuan, USD 72.5)
1 ton wheat bran (1,250 yuan, USD151.03)
125 bags of spawn (187.5 yuan, USD22.65)
- Income: 4 tons of mushrooms (16,000 yuan, USD1933.18)
- Profit: 5,000 bags from January to September can make 14,000 yuan (USD1691.54). It is annual salary level of a public official in China. Though, considering depreciation and failure, actual profit is going to be less than 14,000 yuan.
* currency converter is available at Yahoo Finance
4. Other ground methods for other mushrooms
These are various ground cultivation methods seen in Qingyuan. Though actually some of them were not shiitake, hope inspirable for shiitake growers.
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| Fig 9. Ground method for mid-low temp. strains |
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| Fig 10. Ground method for high humidity area. Alternative field useage after harvest. This method is actually done for wood year mushroom. But it seems not good for shiitake because the harvesting period for shiitake (usually 4-5 months) is much longer than that of wood ear mushroom; so the shiitake substrate may be contaminated during that period throuth the stick form earth. |
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| Fig 11. Other methods. Alternative field useage after crop harvest (during winter season) |
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