Mushroom Cultivation in India: Cost, Procedure, Profit and Methods. There are three major types of mushrooms cultivation in India.
They are:
(1) European button mushroom,
(2) Oyster mushroom, and
(3) Paddy straw mushroom.
European mushroom requires more specific temperature, costly equipments and more investment. The two other types of mushrooms can be very easily cultivated in India. The mushroom cultivation proved to be profitable both at industrial scale as well as part time for unemployed youth and household wives. The economics of mushrooms cultivation are given in Table 21.2.
1. Oyster Mushroom Cultivation:
There are several edible varieties of Pleurotus namely P.ostreatus, P.florida, P.sojor-caju, etc. which are well known for their delicacy and flavour. These species are being grown on commercial scale in various countries. However, in India P.sajor-caju and P.florida are most popular for commercial cultivation. Cultivation of mushrooms are being carried out in mushroom houses. Part of the cultivation requires aseptic conditions, while the other does not require perfect sterile rooms (Fig. 21.3).
(i) Substrate Preparation:
Oyster mushroom can be grown on various substrates viz., wheat/paddy straw, maize stalks, maize cobs, cotton waste, wooden logs, saw dust and vegetable plant residues. Since paddy straw is easily available throughout the year in most parts of the country, it is widely used. One should always prefer to use fresh and well dried paddy straw from which compost is prepared. Both bacteria and fungi of mesophilic and thermophilic are involved in compost preparation. Table 21.3 Major steps in mushroom cultivation are precised in Fig. 21.3 and mushroom growing stages are given in Fig. 21.4.
(ii) Soaking:
Paddy straw chopped into 3-5 cm pieces is soaked in fresh water for 8-24 hours. Old, broken, rotten straw and stagnant water should never be used. Wet substrate is spread on wire mesh to drain off excess moisture.
(iii) Pasteurization:
Water is boiled in a wide mouth container such as a tub or drum. The wet substrate is filled in Gunny bags or basket and closed. The filled bag/basket is dipped in hot water (80-85°C) for about 30-60 minutes and to avoid floating it is pressed with the help of wooden piece.
After pasteurization, excess of hot water should be drained off in a container so that it can be used for other sets. Care should be taken to maintain boiling water temperature 80-85°C, for all sets to achieve pasteurization. Pasteurized substrate is kept inside the chamber where bag filling and spawning has to be done. Once it cools down to room temperature it is filled in bags. The moisture content should be 70%.
(iv) Spawning:
When pasteurized substrate has cooled down to room temperature, it is ready for filling and spawning. At this stage the moisture content should be about 70%. Polythene bags (35 x 50 cm, 150 gauge) or polypropylene bags (35 x 50 cm 100 gauge) may be used for its cultivation. Two percent spawn on the basis of wet straw i.e., one 500 ml bottle spawn (200-250 gm) for 10-12 kg wet straw is used.
Spawning can be done by one of the methods as follows:
(a) Surface Spawning:
Bags are opened and 2% spawn is broadcasted on top and a little ruffling is done to mix it in top layer (2-5 cm thick) and quickly closed.
(b) Layer Spawning:
Substrate is filled and gently pressed at a depth of 8-10 cm and spawn is broadcasted above it. Similarly 2nd and 3rd layers are put simultaneously spawned then bags are closed. This is more suitable when pasteurized straw is filled in bags.
(c) Through Spawning:
Pasteurized straw is mixed with 2% spawn and filled in bags. It is gently pressed and closed for spawn running. This will not be convenient for sterilized polypropylene bags. Spawned bags should be stacked in racks in neat and clean place in a closed position. Temperature of 25 ± 5°C and relative humidity 70-85% should be maintained by spraying water twice a day on walls and floor. At this stage, fresh air requirement is minimum. It takes 20-25 days when bags will be fully covered with white mycelium.
(v) Cropping Picking and Packing:
Once bags are fully covered with mycelium, they are transferred to cropping room, and polythene/polypropylene covers are removed. The open blocks are kept in racks about 20cm apart. Rack should be 60 cm wide and a gap of 50-60 cm between two shelves. There should be 60-75 cm gap between two rows of racks for working. It grows in a temperature range of 20°-33°C (Optimum 25+2°C). Relative humidity 80-85% is maintained by spraying water twice a day but watering on blocks should be avoided for first 2-3 days.
After 2-3 days, light mist spray of water is given on blocks. This is the time when small pin heads appear. Once pin heads are of 2-3 cm size, a little heavier watering is done on blocks and further watering is stopped to allow them to grow. This helps to avoid bacterial rotting. However, the optimum relative humidity must be maintained inside the cropping room. Once mushrooms are 6-8 cms in size, they are plucked, mushrooms should not be allowed to produce spores as it results in poor quality of mushrooms (Fig. 21.6).
After harvesting the first flush about 0.5-1.0 cm outer layer is scraped. This helps to clean remnants of the 1st crop and to initiate 2nd flush. Second flush will appear in about 10 days of 1st flush, similarly, 3rd and 4th flushes will appear in 8-10 days interval. However, almost 80% of crop will be over in 1st and 2nd flushes. Hence, many growers take only 2 flushes. Care must be taken that the beds do not become too wet which may otherwise cause rotting.
Mushrooms should be harvested before watering and their lower portion is cleaned with dry cloth. Mushrooms are packed in perforated (5-6 small holes) polythene or polypropylene bags. It should be sent to the market while fresh. This variety can also be sun-dried by keeping fresh mushrooms in sun for 2 days.
Even polythene sheet may be spread to about 30-40 cm above the mushrooms for quicker dehydration in sun. It can be mechanically dried at 40-45° C. The dried product can be packed in polythene bags for marketing. Dried mushrooms should be soaked in water for 10 minutes before use. Details of oyster mushrooms are precised inflow chart (Fig. 21.6).
2. White Button Mushroom (Agaricus bisporiis) Cultivation:
(i) Spawn Production:
The seed material of mushroom fungi is called spawn. It is in fact, the actively growing vegetative mycelium in a suitable sterile organic matter. The spawn is generally produced in milk or saline bottles. The entire process of spawn preparation should be aseptic from the beginning to the end. The rice straw cuttings, cotton wastes, cotton seed hulls, rice hulls, sorghum grains, rye grains etc., are generally used either singly or in combination for spawn making. The method of spawn production from jawar grains is explained further.
Jawar grain is boiled in an equal volume of clean soft water till the entire water is absorbed by the grain. Later calcium carbonate at the rate of 20 g/kg of grain is added to the cooked material and the mixture is filled in clean dry empty saline bottles upto % full. The mouth of the bottle is plugged with non-absorbant cotton. The cotton plug and a part of the bottle neck is covered with a clean 10 cm square paper bit and tie it with twine or rubber band.
Sterilize the bottles in a pressure cooker or autoclave at 15 lb pressure for 1 ½ hours. After cooling, a small quantity of the fungal culture should be inoculated to the bottle in an inoculation chamber. On incubation at 25° C for about 2 weeks the fungus covers the grain in the bottle. This is called spawn.
Button mushroom is the most popular in all the countries. U.S.A. is the maximum button mushroom producing country. Agaricus bisporus is cultivated in many countries. Recently A.bitorquis is also introduced. It requires slightly higher temperature for cropping. White button mushroom cultivation includes the following steps (Fig. 21.7).
In ancient times composts made of horse dung and cow dung were used. But now-a-days synthetic compost made out of grain crops straw is widely used. In south India locally available substrates like paddy straw, ragi straw, maize straw, horse dung and chicken manure are used. Paddy straw or mixture of paddy straw and maize straw form a good compost.
Two compost formulae and the method of compost preparation are given below (long method) –
Paddy straw watered for 2 days to have moisture content 75-77% is mixed with fertilizers and stacked in a heap of 1.65 – 1.8 x 1.65 – 1.8 m or required length and turned on 6th, 10th, 13th, 16th, 19th, 22nd, 25th and 26th day. On 10th day chalk powder and on 13th day gypsum are added. On 26th day the substrate compost will be ready. It is filled into trays, boxes or shelves to make the so called beds and transferred into the room of pasteurization.
Pasteurization is a partial sterilization process operated at low temperature. Live steam generated from a water boiler is introduced to compost for 2 hrs so as to have air temperature 60-62°C. Maintain this temperature for 2 hrs and then introduce a gentle steam of fresh air to lower the temperature for the next 6-8 hrs.
The objective of pasteurization of compost is to keep away the insects then pests in the substrate then spores of contaminating microorganisms then bring the temperature of compost uniformity to 50- 55°C which promotes decomposition of the substrates by thermophilic microorganisms (Table 21.4). Through this final adjustment a more selective medium favouring the growth of the mushroom is accomplished. Carelessness at this stage may lead to a crop failure.
Note:
Each kg of mushroom is equal to 0.5 kg meat, 2 ½ egg, 1.5 kg potato, 0.5 kg soyabean and 1.0 kg pulses.
(iii) Spawning:
The spawn is spread over the surface and covered with a thin layers of compost. The growth of active mycelium in the beds is called spawn running. Spawn running requires 15-20 days at 90 to 96 percent relative humidity R.H. and 25 ± 2°C temperature.
(iv) Casing:
After spawn running, the beds are covered by casing material (thin layer of pasteurized material) continued incubation for another 8-10 days, i.e., till pin heads start appearing. At this stage the temperature is lowered to 16 ± 18°C and fresh air is introduced. Watering the beds is to be carried out as and when required.
(v) Cropping:
The crop starts producing mushrooms in 3rd week after casing and continue for 10-12 weeks. Mushrooms are picked by griping the cap and twisting when they are in button stage.
Mushrooms or fruit bodies appear in rhythmic cycles which are called flushes or breaks. Generally, a large and more number of mushrooms are produced in first four flushes. After the fourth flush smaller and less number of mushrooms are produced. Hence, beds are usually removed after the fourth flush. The spent out bed material can be used as a manure.
3. Paddy Straw Mushroom Cultivation:
The paddy straw mushroom Volvariella volvacaea prefers to grow on paddy straw, hence it is known as paddy straw mushroom. Though its cultivation started in China during 18th century, its cultivation in India is only in 1960 at Coimbatore, Tamil Nadu. Three species of this genus, V.esculenta, V.volvacea and V.diplasia are being cultivated in India.
At the beginning it used to be grown on twisted 10 kg paddy straw soaked in water and placed on wooden platform (75 x 75 x 30 cm) in a haphazard manner. The paddy bed is spawned with 3rd twist. The whole bed is covered with the polythene sheet to maintain moisture. Recently polybag method was developed by Bahl (1982).
The method has following steps:
1. Chop the paddy straw and soak in water for 24 hrs.
2. Cut waste paper into small pieces and soak for the same period.
3. Decant water after 24 hrs.
4. Mixed thoroughly the chopped straw, paper pulp and spawn.
5. Fill the mixture in polythene bags.
6. Puncture the bags with needle to facilitate the exchange of air and drain the water.
7. Tie the month of polyethylene bag. Keep them on wooden rock at 35-40°C
8. Maintain the humidity of the contents to about 80-90°RH by sprinkling water
9. At the end of 10-15 days small pin heads of mushrooms appear which grow into matured mushroom within 2-3 days.
10. Harvest mushroom while they are tender before starting spore production.