|Bioconversion of Organic Residues for Rural Communities (UNU, 1979)|
|Mushroom production technology for rural development|
Materials and methods for growing mushrooms under natural or field
Growing mushrooms under semicontrolled conditions
Results and discussion
R. V. Alicbusan
National Institute of Science and Technology, National Science Development Board, Manila, Philippines
One of the low-cost, appropriate technologies being offered by the National Institute of Science and Technology, National Science Development Board (NIST-NSDB) for rural development is the production of the tropical mushroom Volvariella volvacea (Bull ex Fr.) Singer. This variety of mushroom usually grows on piles of decaying rice straw, sawdust, coffee pulp, sugar-cane bagasse, oil palm extraction wastes, etc. The mycelium grows outward towards the sunlight, which stimulates the growth of small nodules called pin-heads. These small white bodies are approximately the size of the pins Filipino women wear in their hair, hence the name. Great numbers of them develop almost simultaneously all along the sides of the growth substrate. Within two to three days the clour changes from white to black, then to brown, and gradually fades as the mushrooms grow larger. There are, however, some strains that are dark brown or black. They may be chestnut- or egg-shaped.
The young mushroom is covered initially with a thin membrane called the volva As the mushroom develops, the stem or stipe elongates, gradually pushing the cap upwards, which causes the volva to rupture and remain at the base of the stem. The still unopened mushroom cap is further pushed up to a height of about 6 to 10 cm. Once the stem reaches its maximum height, the cap starts to expand. Initially, the gills are white, but they turn brown once mature basidiospores are produced in the gills. The opened mushroom has a stronger odour and taste attributable to the mature basidiospores.
Figure 1 illustrates the stages of growth of this variety of mushroom. Growth to maturity usually takes five to seven days, depending on the prevailing environmental conditions. Low temperatures (25 - 27°C) slow down development and high temperatures (28 - 35 C) hasten the rate of growth.
The recent expansion of the commercial production of this tropical mushroom in the Philippines is the result of several complementary factors: (1) there is technology available and the climate is favourable to good mushroom production throughout the year; (2) there is plenty of manpower available, ample space, and abundant bedding material; (3) there is high demand for the product both locally and abroad; and (4) financial assistance can be extended by government and private lending institutions.
Given these available resources, field demonstrations were conducted to show farmers simple methods of mushroom culture in different regions of the country. This was done through the 17 regional offices of the NSDB. To hasten the dissemination of the technology, all the Science Field Officers of NSDB were given one month of intensive training in mushroom production. Each regional office was provided with facilities for making mushroom spawn as well as space for mushroom demonstrations, including the construction of a single unit mushroom house.
Seminars were conducted in different barrios to make the people aware of available technology for home mushroom production. There are also technicians in the Tropical Mushroom Research Laboratory at NIST who can extend technical assistance in spawn and mushroom production in different regions.