Download - Indoor Cultivation of Paddy Straw Mushroom
Indoor cultivation of paddy straw mushroom,
Volvariella volvacea, in crates
RENATO GUTIERREZ REYES
Center for Tropical Mushroom Research and Development,
Department of Biological Sciences,
College of Arts and Sciences, Central Luzon State University,
Nueva Ecija, Philippines
The paddy straw mushroom, Volvariella volvacea (Bull.: Fr.) Singer, is
considered to be one of the easiest mushrooms to cultivate due to its
short incubation period of 14 days. It is a tropical species that thrives
best at 30-35°C for mycelial development (Reyes et al., 1998a) and 28-
30°C for fruiting body production (Reyes et al., 1998b). Being
cellulolytic, the paddy straw mushroom can be grown on a number of
cellulosic substrates such as cotton wastes, sugarcane bagasse, rice
straw and stubbles (Chang, 1993; Khan and Dogar, 1991;Reyes et al.,
1998b).
The mushroom is traditionally cultivated on beds made of
uncomposted and unpasteurized bundles of banana leaves or rice
straw, tied at both ends and laid one on top of the other to form a bed.
Mushroom beds which are exposed directly to the sun are covered with
plastic sheets. However, the yield on mushroom beds isunstable and
irregular, since the bed is subjected to microbial contamination and
fluctuating environmental conditions. In order to improve and increase
productivity, a step by step procedure on the indoor cultivation of
paddy straw mushroom using rice straw as the main substrate is here
described. The indoor cultivation method has three salient features:
compo sting, pasteurisation and cultivation insidea mushroom house
using stacks of open wooden crates. Composting is an important
process that allows he microbial decomposers to reduce the tensile
strength of the rice straw. This also prepares the straw for easy
colonization by the mycelium of the paddy straw mushroom.
Pasteurization, on the other hand, is a critical process that eliminates
undesirable microorganisms which may compete with the paddy straw
mushroom during production. It also further renders the composted
rice straw more suitable. The cultivation of mushrooms in growing
houses reduces the sudden fluctuations of temperature and relative
humidity associated with outdoor production which can be hazardous
to growth and fruiting body production. The general procedure for the
indoor
cultivation of paddy straw mushroom is outlined as follows and the
sequence of processing the various stages is given as instructions.
Ingredients
100 kg bale of dry straw
1 kg molasses
0.5 kg complete fertiliser (14% N: 14% P: 14%K)
1.0 kg agricultural lime
10-20 kg spawn for each 100 kg of pasteurised
Compost
Fig 1 Compo sting of rice straw in preparation for the indoor
cultivation of the paddy straw mushroom.
Soaking
Rice straw including stubbles is used as the main substrate for indoor
cultivation of the paddy straw mushroom. Unlike the traditional
method
(bed type) of utilization of this species, rice straw of any type or age
can be utilised. The rice straw is soaked overnight in clean tap water.
Soaking is an important process since it softens the strands of straw
which facilitates the composting process.
Composting
The soaked rice straw is removed (Fig 1) and incorporated with 1%
molasses and 0.5%commercially available complete fertiliser in the
compost pile. The composting period takes 14 days. During the first 7
days of composting, the compost pile is covered with plastic sheets to
induce the growth and proliferation of thermophilic decomposers.
Three days later, the partially composted rice straw is shredded using
a
spading fork to release the residual gases such as ammonia which are
toxic to the growth of the mushroom.
Mix 1% agricultural lime thoroughly into the partially composted
substrates, continuing the composting process for 7 more days to
complete the 14-day period. At the end of composting, the composted
substrate is shredded for aeration.
Wearing a dust mask is advisable when breaking out fresh dry straw\
Crating
Use a wooden open crate measuring 15 x 45 x 60
em. Shred by hand the composted substrate while
packing to fully liberate the residual toxic gases
like ammonia which have accumulated during
composting (Fig 2). The presence of ammonia in
the composted substrate stimulates the growth of
weed mushrooms (Coprinus
cinereus) and thus should be
avoided. The composted
substrate is compressed into
the wooden crates and this
may be facilitated by use of a
suitably shaped press.
Housing of crates
The arrangement of crates in
the mushroom growing
house should not obstruct
the uniform circulation of
hot moist air during
steaming. The steam pipes
should be installed and
extended on the floor of the
mushroom growing house.
Proper arrangement of crates
also permits efficient circulation of air and uniform distribution of light
during incubation and fruit ing. A mushroom
growing house should not necessarily be made
from concrete and can be made from light
materials available in the locality to reduce cost .
Environmental parameters like temperature, air
circulation, light penetration and the distribution
and maintenance of relative humidity should be
taken into consideration.
Steaming
Steam is introduced into the mu shroom house
through the steam pipelines to pasteurise the
composted substrates in the crates. Steaming
should be immediately undertaken after crating, and eliminates the
undesirable microorganisms
which may compete with the paddy straw
mushroom during incubation. A compost
temperature at 60°C for 4-6 hours is best during
steaming. It is advisable to start steaming in the
afternoon, and the temperature of the compost
should gradually go down to 52°C during the
night.
Fig 3 Button stages of the paddy straw mushroom growing on
previously composted rice straw.
Spawning
Prior to spawning, the temperature of the
steamed composted substrate should be no higher
than 30°C. Spawning is a critical process whereby
the viable mycelium of the mushroom, aseptically
grown on agricultural waste such as tobacco
midribs (Reyes, 1991), is inserted into the
steamed composted substrate the morning after
steaming. The spawning rate is 10 to 20 percent
based on the fresh weight of the substrate.
Incubation
Incubation allows the colonization of the
substrate by the mycelium of the paddy straw
mushroom, using an air temperature in the house
at 30°C. Mycelium grows luxuriantly at 35°C and
85% relative humidity and it takes 7-10 days to
fully colonize the substrate. Once mycelial
colonization is complete, observe the formation of
fruiting primordia or initials and introduce
minimal ventilation and light penetration into
the house to stimulate synchronised fruiting.
Lower the air temperature in the house from
30°C to 25°C gradually until the desired
temperature is attained. This is done by
sprinkling fresh water on the floor. This stage
(formation of fruiting primordia) is one of the
most critical stages since poor control of physical
parameters like temperature, ventilation and
light would lead to abortion of the fruiting
primordia. It takes 2-3 days for the complete
development of these primordia into buttons of
marketable size.
Fruiting and harvesting
Harvesting is usually done early in the morning
and late in the afternoon to prevent excessive loss
of moisture and opening of mushroom buttons.
Mushrooms are harvested at the button stage (Fig
3). Care should be observed so as not to damage
the growing buttons which are still developing.
Harvesting may be facilitated by holding the
button and twisting followed by an upward pull.
Sorting and marketing
Clean the harvested mushrooms by removing
the rice straw attached on their bases. Separate
the buttons, which command a higher price than
the open mushrooms and pack them in
perforated plastic bags or styrofoam boxes ready
for marketing. Do not refrigerate the paddy
straw mushroom, which would make it soft and
watery!
Acknowledgement
The support of the Central Luzon State
University Spawn and Mushroom Production
Project and its technical staff (Claire Dalit,
Milagros and Ernesto Tabago, Conrado
Aguinaldo, Reynaldo Pascual, Ernesto Sanchez,
and Oscar Roque) in the Philippines while the
author was the Project Manager is gratefully
acknowledged. Also to the members of Economic
Biology class where mushroom production was
integrated as one of its laboratory exercises.
References
Chang, S. T. (1993). Biology and Cultivation Technology of Volvariella
volvacea. In Mushroom Biology and Mushroom Products, (edited by
Chang, S. T., Buswell, J . A. & Chiu, S.) Hong Kong: The Chinese
University Press.
Khan, S. M. & Dogar, M. A. (1991). Some studies on the cultivation of
Chinese mushroom (Volvariella volvacea) on sugarcane industrial by-
products. In Science and Cultivation of Edible Fungi (edited by Maher,
J . M.). The Netherlands: A. A. Balkema Publishers/Rotterdam.
Reyes , R . G. (1991). Volvari ella spawn substrate formulation and
preparation. In Mushroom Culture and Fertiliser Production. Philippines:
Central Luzon State University Press.
Reyes, R. G., Eguchi, F., Iijima , T. & Higaki, M. (1998a). Physiological
considerations for the efficient mycelial colonisation of Volvariella
volvacea. Journal of Wood Science44: 408-413.
Reyes, R. G., Eguchi, F., Iijima , T. & Higaki, M. (1998b).
Environmentally controlled spawn formulation for fukurotake,
Volvariella volvacea. In Abstracts of the 48th Annual Meeting of th e
Japan Wood Research Society.Shizuoka, Japan.