Note: Descriptions are shown in the official language in which they were submitted.
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SUMMARY OF THE PRIOR ART
The best known prior art is applicant's U.S. Patent No.
4,079,543 issued March 21, 1978 (Canadian Serial No. 290,626,
filed November 10, 1977) wherein shredded newspaper is employed
as the water absorptive material. The present invention is an
improvement thereover since the materials employed as water
absorptive materials in accordance with the present invention
are materials with very little market value and, in fact,
frequently constitute a waste disposal problem. Accordingly,
these materials which have no value or at most have a very low
value have been successfully employed as mushroom casings which
are capable of replacing shredded newspaper and the even more
expensive peat.
~UMMARY OF Æ INVENTION
In growing mushrooms it is a universal practice to "case"
the beds by placing a layer of material over the mushroom bed
after the spawn haæ permeated the compost. This casing layer
is usually one to two inches thick, and originally was loam
soil. In 1947 I discovered that peat could be substituted for
this loam soil. I described my experiments and commercial
practice in my articles, "Studies on the Function of the Casing
- for Mushroom Beds," Part I, Part II and Part III in the
October 1952, November 1952 and December 1952 issues of the
Mushroom Growers' Association Bulletin, published in London,
England. Other materials such as vermiculite, gravel, crushed
brick and ashes have also been proposed.
The purpose or function of the casing material is to pro-
vide a medium which is insufficient in nutrients so that the
mycelium growing into the casing is unable to form the poly-
phenol oxidase enzymes, which in turn produce the quinones that
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prevent fruiting. (The quinones are useful to the mushroom as
a defensive mechanism, but must be destroyed in order to induce
fruiting.) The alkalinity and reducing substances occurring in - r
the casing also serve to destroy these quinone inhibitors vola-
tilizing into the casing. The casing also serves as an addi-
tional source of moisture. The reducing substance is prefer-
ably activated carbon.
At the present time peat is widely used for casing mush-
i~ room beds, but peat reserves suitable for casing mushroom beds
are now being depleted. Also, the cost of baling and trans-
porting peat is becoming expensive so that it would be highly
desirable to provide a relatively inexpensive substitute for
the peat.
Although various synthetic casings for mushroom beds have
been proposed, none have produced the large yields to compete
with peat, or have been too expensive to have any practical
application. In the formulas for a synthetic casing to be
presented, I have discovered how to make a practical formula
for commercial practice and a formula which will produce yields
even higher than those obtainable with peat.
In accordance with the present invention, an inexpensive
material that is highly absorptive to water is combined with
activated carbon to adsorb, remove or destroy emanations
derived from mycelium that prevent fructification.
In ~addition, a casing material is provided which in some
embodiments produces a much higher yield of mushrooms than can
be obtained with conventional casing materials.
In accordance with the present invention an inexpensive
material that is highly absorptive to water is combined with
activated carbon to adsorb, remove or destroy emanations
derived from mycelium that prevent fructification. These
materials are of extremely low commercial value or even waste
materials which form a disposal problem.
Accordingly, it is an object of the present invention to
provide a casing material wherein the bulk of the material is
made from an otherwise worthless, or at least low value, ab-
sorptive material.
Various other features and advantages of the invention
will be brought out in the balance of the specification.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with the present invention, a material which
is highly absorptive to water, preferably a fibrous material
known as clarifiber, hereinafter defined, spent mushroom com-
post, or less preferably, cottonseed hulls. With any of these
water absorptive materials, it is necessary to employ limestone
and activated carbon. Since the clarifiber as delivered ordi-
narily contains from 40 to 50 percent by weight of water, it is
ordinarily not necessary to add any water to the material.
However, the material is ordinarily too compact as received and
is preferably shredded before use. For each 600 grams of the
moist clarifiber one may employ 12 to 30 grams of activated
carbon and 300 to 600 grams of limestone. The limestone is
preferably granular with the granules somewhat larger than
ordinary granulated sugar. Larger particles up to approxi-
mately one-eighth in diameter may be employed.
The clarifiber is a sulfite pulp waste product defined as
follows:
A cellulosic fibrous material known as "clarifiber,"
generated by Georgia-Pacific Operations, Bellingham, Washing-
ton, and by other paper-making companies in the manufacture of
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sulfite pulp, is a waste product usually disposed of by burn-
5~ ~
ing. The major components of the "clarifiber" are as follows:
Pulp fiber (46% softwood sulfite, 32% chem-mechanical
and 22% softwood kraft)
Sulfite screenings (partially digested wood and bark).
The minor components are as follows:
Sand, small rocks and shell pieces.
As this cellulosic fibrous material leaves the paper-
producing plant for shipment, it contains 40% to 50% by weight
water, has a pH of 4.0 to 6.5, and has a shipping density of 33
lbs. per cubic foot.
Another material which is suitable for use in the present
invention is the so-called "spent compost" which results from
mushroom growing. This is compost on which a crop of mushrooms
has been grown and is an unsuitable substrate by itself to use
in growing another crop of mushrooms. Although this material
is a valuable fertilizer, muæhroom growers tend to congregate
in relatively small areas so that in those areas where mush-
rooms are grown, there is a poor, if any, market for the spent
compost. In the past, this spent compost has often been put
out into fields and allowed to weather for a few years, where-
upon it can be used as a casing material. The loss of material
in this manner is considerable so that this method of disposal
and reuse is not ordinarily satisfactory.
In accordance with the present invention, it has been
found that the spent compost can be mixed with activated car-
bon, calcium carbonate, e.g. chalk or limestone, and water and
c
used as a casing. This is another example of a fibrous mate-
rial which has little or no value and which can replace the
costly peat as a casing material. Preferably, the spent com-
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post is washed with water to remove soluble salts but this isnot necessary in all instances. Also, the spent compost is
preferably sterilized either by heat or with a chemical agent
such as propylene oxide, if dried, or as a preventive measure
in an old crop house.
Another cellulosic fibrous material which may be used is
cottonseed hulls which are a by-product of pressing cottonseed
oil. This material is less preferable than the clarifiber
mentioned above since the hulls are frequently infested with
insects, mites and nematodes and they may additionally contain
mold spores. Accordingly, to make this material suitable for
use as a synthetic casing, it must be fumigated or sterilized
with steam or propylene oxide. Good results were obtained by
fumigating with propylene oxide at the rate of 10 milliliters
of propylene oxide per 1 lb of cottonseed hulls. Heating for
24 hours at 140 degrees F. was also useful for destroying
pests, but was not quite as satisfactory as fumigating.
Since the cottonseed hulls are dry, water must be added
preferably so that the wet hulls have a water content of 40 to
50 percent by weight. The amount of carbon and limestone can
be the same as with the clarifiber.
The following working examples illustrate preferred
embodiments of the invention:
To conduct tests with these materials, mushrooms were
grown as follows: spawned compost was filled in approximately
5 gallon plastic pails, 10 inches deep, and having a surface
area of approximately 1/2 sguare foot. The synthetic casing
was applied in a layer one inch to two inches deep. The mush-
rooms were both the brown and cream strain types and were
picked for 15 days to determine the yield. The following
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. .
casing formulations were employed and the yield shown in pounds
per pail, calculated on basis of pounds per square foot, of cut
mushrooms. ~ -
1. Shredded clarifiber - 600 grams
Granulated Iimestone - 400 grams
Activated carbon ~arco-S-51) - 20 grams
pH of mixture 7.5 Yield - 5 to 6 lbs. per sq. ft.
2. Shredded clarifiber - 600 grams
Large particle limestone (approx. 1/8" diam.) -
500 grams
Activated carbon (Darco-S-51) - 20 grams
~~ pH of mixture 7.5 Yield 5 to 6 lbs. per sq. ft.
3. Sterilized cottonseed hulls - 400 grams
Granular limestone - 500 grams
Water - 600 milliliters
Activated carbon ~Darco-S-51) - 20 grams
- Yield 4 to 5 lbs. per sq. ft.
pH of mixture 7.5
4. Dried spent compost - 300 grams
Activated carbon - 30 grams
Granulated chalk - 500 grams
Water - 500 milliliters -
-~ pH of mixture - 7.5
; Yield - 5.3 lbs. per sq. foot.
5. "Spent" compost from mushroom bed or tray was heated
to approximately 140F for 12 hours and then fumigated with
formaldehyde (the usual practice in emptying an old crop before
refilling)-
The casing layer was then stripped off.
The spent compost was washed and mixed with water at therate of 4 lbs. water to one lb. of "spent" compost, in a paddle
mixer or other type of mixer.
The mixing in water was continued for approximately 2
minutes, using caution not to overmix and destroy the fibrous
structure of compost.
The compost was decanted and emptied on a screen, followed
by draining off excess water on screen, pressing out excess
water, and refilling washed compost into mixer.
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' '
To 1200 grams of wet spent compost, add in mixer:
Granulated chalk - 500 grams
Activated carbon - 30 grams
pH 7.5
Yield - 1.9 lbs. per sq. ft. in first break - 6
; days pick.
(This experiment was conducted in trays, 4 x 4 feet
square, at Ariel Mushroom Farm. Average yield for 11 con-
trol trays for first week was 1.2 lbs. per sg. ft. Average
yield for non-washed compost to which activated carbon and
limestone were added same as to washed compost, yield 1.2
lbs. per sq. ft.)
