Cultivation technology of Paddy straw mushroom

The paddy straw mushroom is having good combinations of all attributes like flavour, aroma, delicacy, high content of protein and vitamins and minerals, because of which, the acceptability of this mushroom is no way less than much popular white button mushroom. It is an edible mushroom of the topics and subtropics, and began to be cultivated in China as early as 1822. Around 1932-35, the straw mushroom was introduced into the Philippines,

Malaysia, and other south-east Asian countries by overseas Chinese. Since then, its cultivation has been conducted in various countries outside of the region. The fruiting body formation starts with tiny clusters of white hyphal aggregates called primordia and it is followed by several morphological stages in the fruiting body development process. The successive stages are called as "button", "eggs", "elongation", "mature" stages respectively. Differentiation can be seen first at the 'button' stage. At maturity the buttons enlarge and umbrella like fruit bodies emerge after the rupture of the volva.

Fresh dried straw is most suitable for its cultivation. The straw is tied into bundles of 1.2m long x 25 cm dia (tie end) size followed by steeping of bundles in water in a cemented tank for 24 to 48 hours. The bundles are taken out and put on a cemented floor for few hours for draining out the excess water. The mushroom beds are prepared on a raised bamboo platform inside a thatched hut. Four pre-wetted bundles are placed side by side on this platform, facing all the loose ends on one side. Then another four bundles are placed with their tied ends on the opposite side. The loose ends of all the 8 bundles meet and overlap each other in the middle. Spawn is applied on this first layer about 15cm away from the outer edge. On top of the spawned Ist layer, a little quantity of gram dhal powder (about 200g per bed) is applied along with the spawn. On top of the spawned Ist layer of eight bundles again a second layer of 8 bundles is placed in a similar fashion and spawned. A third layer is again laid on top of the second layer and followed by 4^th layer of bundles and spawning. All these 32 bundles make a single bed which is now pressed to remove the entrapped air and make it compact for effective spawn run. In order to avoid rapid water loss, the beds are covered with polythene sheets or gunny sheets.

 

Spawn of Paddy straw mushroom:

Spawn of this mushroom is made on grains of cereals or millets and is called grain spawn. Sometimes it is also made on soaked chopped paddy straw. This spawn is called straw spawn. Spawn may be available locally from the Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, New Delhi-llOO12 at nominal price. Spawn is also available from Plant Pathology or Microbiology Departments of the respective Agricultural Universities. One bottle of spawn is sufficient for one bed.

 

Cultivation Technology:

A variety of waste materials have been used for cultivation of the paddy straw mushroom, which include: paddy straw (Chang, 1965), water hyacinth (Chang & Mok, 1971), oil palmbunch (Naidu, 1971), oil palm pericarp waste, banana leaves & saw dust, cotton waste, sugarcane bagasse  etc. Paddy straw mushroom prefers high cellulose, low lignin containing substrate and produces a family of cellulolytic enzymes (. The cultivation of Volvariella is lesssophisticated, less extensive and  can be rewarding in tropical & subtropical climates.

Before 1970, it was only paddy straw, which was in use for paddy straw mushroom cultivation. However, in 1971, cotton waste (Ginning mill waste) was first introduced as the heating material for growing of strawmushroom followed by complete replacement of paddy straw with cotton waste by 1973 in Hong Kong. This was practically the turning point in the history of paddy straw mushroom because cotton waste gives a higher and more stable yield (30 to 40%) along with early fructification and harvesting. After adoption of cotton waste, the cultivation of paddy straw mushroom has become semi-industrialized in Hong Kong, Taiwan, Indonesia, China & Thailand.

The common methods employed for paddy straw mushroom cultivation are given below:

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·         CONVENTIONAL METHOD

·         IMPROVED CAGECULTIVATION

·         OUTDOOR METHOD

·         INDOOR METHOD

·         CIRCULAR METHOD

·         INDIGENOUS CHINESE CULTIVATION PRACTICE

Conventional method:

·         Preparation of paddy straw bundles of 0.75 – 1.0 kg (80- 95cm long & 12.16cm wide) preferably from hand threshed paddy.

·         Immersing of bundles in clean water for 12-18 hours in a cemented water tank.

·         Draining out of excess water by placing bundles on raised bamboo platform.

·         Making bed by placing 4 bundles side by side and another four bundles similarly but from the opposite side, forming one layer of eight. The open ends of bundles from opposite sides should overlap in the middle.

·         Forming of second, third & fourth layer by intermittent spawning between first and second, second and third and third and fourth layers.

·         Spawning on entire surface of the layers of the beds at a space of 5cm apart leaving margin of 12-15cm from edges.

·         Sprinkling of red gram powder over the spawned surface.

·         Using 500 gm spawn and 150 gm of red gram powder for a bed of 30-40 kg of dried paddy straw.

·         Pressing of bed from the top and covering with clean plastic sheet for maintaining required humidity (80-85%) and temperature (30-350C).

·         Removing of plastic sheet after 7-8 days of spawning and maintaining temperature of 28-320C and relative humidity about 80%.

·         Mushroom will start appearing after 4-5 days of sheet removal and will continue for next 20 days.

·         After crop harvest the substrate can be used for manure in the field.

Outdoor method:

The best place to cultivate paddy straw mushroom outdoor is in shade created by trees or creepers. The steps involved are as follows.

• ·         Preparation of raised platform either with sand or bamboo poles or wooden planks or bricks.
• ·         Preparation of bundles of 40cm length and 10 cm width.
• ·         Soaking of bundles in running water or in 2% CaCO3 solution.
• ·         Driving of bamboo pole into the center of each end of the bed.
• ·         Preparation of layer of bundles followed by spawning.
• ·         Laying down of 4 layers of bundles during summer months and 7 layers during rainy season.
• ·         Topping of bed with 20cm deep layer of rice straw followed by covering with polythene sheet.
• ·         Removing of polythene sheet after 4 days and sprinkling of water carefully on 6th day. Spraying of water can be avoided during rainy season.
• ·         Prohibit spraying of water after appearance of the mushroom pinheads.

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Important steps for obtaining healthy mushroom crop:

·         Compost moisture in the range of 60 to 65%.

·         Immediate spawning on obtaining compost temperature at 350C followed by covering with plastic sheets, which should be maintained for next 4 days.

·         No ventilation during first 3 days following spawning.

·         Removal of plastic sheets after 4 to 6 days of spawning and sprinkling of water on bed surface followed by ventilating the cropping room.

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Harvesting:

The straw mushroom is harvested before the volva breaks or just after repture. These stages are called as the button and egg stages. This mushroom grows at high temperature and moisture, therefore, its growth is very fast. So, for harvesting of straw mushroom at good condition it has to be harvested twice or thrice in a day (morning, noon & afternoon). This mushroom usually takes 9-10 days from spawning to first harvest of crop and the first flush normally lasts for 3 days, which constitutes about 70 to 90% of the expected mushroom yield. The intervening period of 3 to 5 days requires thorough watering and maintenance of optimum conditions inside the cropping rooms. The next flush will again lasts for 2-3 days and yields less mushroom than the first flush. The second flush adds only 10 to 30% of the total crop.

The mature fruiting bodies should be carefully separated from the beds/substrate by lifting and shaking slightly left or right and then twisting them off. The mushrooms should not be cut off by knives or scissors from the base of the stalk, because the stalk left behind on the bed/substrate will rot and be attacked by pests and contaminated by moulds, which in turn will destroy the mushroom bed.

Processing:

Straw mushroom is more perishable than other edible mushrooms and can not be stored at 40C as it undergoes autolysis at this temperature (Ahlawat et al. 2006). This mushroom can be stored at a temperature of 10 to 150C for 3 days and little more at 200C or under controlled atmosphere storage. The loss of moisture in 4 days stored mushroom could be as high as 40-50% in unpacked mushroom, while it can be reduced to 10% on packaging in perforated polythene begs. Straw mushroom can be processed by canning, pickling and drying. However, practically the straw mushroom from China to Hong Kong is transported in wooden cases, in which the two compartments of the case are filled with ice, while the central compartment with mushroom. On the other hand, this mushroom is transported by air from Taiwan to Thailand in bamboo baskets with central aeration tunnel and packed with dry ice wrapped in paper. However, like button mushroom, more research work is needed in this mushroom also for studying the effect of blanching, post harvest storage, soaking and other chemical treatment before canning in order to increase the drained weight and improve the quality of the canned product.