Note: Descriptions are shown in the official language in which they were submitted.
` 1 132874~
water Retentive ~atrix Incorporating Plastic for Growing
Seeds and Plants
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Technical Field
. ~ 5 This invention relates to a water retentive matrix
- composition for improving germination rates, retaining
water, and, when used as an encapsulating material, for
protecting ~eeds from predation and mechanical injury
with application in the fields of forestry, agronomy, and
commercial and amateur horticulture.
Background of the Invention
Currently, the replanting of harvested commercial
forest acreage requires labor-intensive planting methods.
Year-old nursery-raised, bare-root tree seedlings are
transplanted by hand or semi-mechanized equipment to open
- woodlands. This is a costly and time-consuming procedure
necessitated by the delicacy of the plants. Light and
water needs of bare-root seedlings require very careful
handling with specialized environmental controls such as
refrigeration or misters to prevent overheating or drying
out while in transit. The seedlings are bulky, often
become root-bound and have limited periods for
transplantation. Survival rates of only 70% are
considered the best obtainable with current practices and
under optimum conditions.
Other agricultural markets face similar limitations
of pre-grown seedlings. Commercial vegetable farming
relies on pre-grown seedlings of tomatoes, tobacco, and
cabbage. Home gardeners also make heavy use of pre-grown
seedlings.
Seeding directly into fields would be preferred in
the forestry industry, but to date this has proved
ineffective due to the high seed mortality from predation
and the lack of predictable moisture and light. A
protective material to encapsulate the seed is a means of
protecting the seed from these dangers and of improving
germination rates.
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~` 132874~
The idea of encapsulating seeds to improve
germination i8 known. For instance, U.S. Patent No.
4,628,633 uses compressed peat moss enclosing the seed to
absorb water to form a loose, partially light-
transmitting structure. Planting is simplified since theencapsulated seeds will dry out less quickly and can be
shipped more cheaply and conveniently in less space than
pre-grown seedlings. The rounded shape of encapsulated
seeds permits bulk handling methods.
However, there are additional qualities not
possessed in peat alone that can be achieved by a novel
composition of materials. Total mechanization of
planting would be possible through use of improved
encapsulated seeds. The semi-mechanized planting of
bare-root timber seedlings, for example, require a deep-
shank plow to plant the seedlings deep enough into the
soil. In contrast, encapsulated seeds need a shallow
planting depth, which reduce~ the horsepower needed for
the machine, increases the speed of the operation, and
permits machine planting on otherwise unsuitable sites.
Hand planting, the mo6t expensive method in time and
cost, is faster with encapsulated seeds than with bare-
root seedlings. Encapsulated seeds are easier to handle
-~ and more can be carried by the hand-planter than can
- 25 bare-root seedlings. In addition, encapsulated seeds
will not dry out as quickly.
Whether planted by machine or by hand, encapsulated
seeds do not experience the transplant shock found in
bare-root seedlings. Misplanting, resulting in "J"- or
"L"-shaped root seedlings which are unable to produce a
desirable tree, is eliminated. The better protected
encapsulated seed is plantable during a longer window of
time, permitting coordination with herbicide application,
a cost-savings not now available. However, known
matrices have not produced the advantages cited to the
degree needed by the industry.
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:~ ~32874~
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An improved matrix for encapsulating seeds is needed
to better protect the seed and so to improve germination
and survival rates above the industry average of 17%
after twenty-eight days. The improved matrix must
reflect a balance between the water absorbance capacity
of the encapsulating matrix and it8 structural integrity.
The matrix should accommodate the addition of nutrient~,
fungicides, fertilizers and dyes. Under proper
conditions, it should permit the aerial planting of
seeds. In addition, the matrix may be substituted for
conventional potting soil.
Summary of the Invention
Applicants' invention is in part a matrix
composition for protecting seeds against injury and
- 15 enhancing the conditions for germination and growth of
; seed~ and plants. The matrix comprises 55 to 80 percentby dry weight of a hydrophilic fibrous bulking agent,
- 0.001 to 0.35 percent by dry welght of a non-ionic
- surfactant, ~ to 40 percent by dry weight of a
- 20 substantially fully hydrolyzed (90-100%) poly(vinyl
alcohol) of a molecular weight between 10,000 and
50,000, water in an amount of between 10 and 25 percent
by weight of the composition, and 5 to 20 percent by dry
~ weight of a water retentive polymer with a water
;- 25 absorbtivity of between 50 and 600 times its weight.
- Preferably, Applicants' invention is a matrix composition
comprising 73 percent by dry weight of peat, 0.2 to 0.35
percent by dry weight of polyoxypropylene-polyoxyethylene
block copolymer, 11 to 13 percent by dry weight of a
substantially fully hydrolyzed poly(vinyl alcohol) with a
molecular weight of approximately 50,000, and 14 to 16
percent by dry weight of potassium acrylate acrylamide
copolymer. Water is added in an amount of 10 to 14
;`; percent as measured against the dry elements to activate
the polymer.
Detailed Description of the Invention
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-~ Applicants have invented a water retentive matrix
that permits improved germination rates in seedlings and
can be used advantageously as a potting soil substitute
for plants. The instant invention solves the problems
inherent in bare-root seedling transplantation methods
described above. The matrix material provides an
environment that balances (1) sufficient retention of
water in the matrix to sustain the ger~inating seedling
and (2) sufficient structural integrity of the matrix to
- lo protect the seedling from mechanical injury and
predation. The matrix when wetted yields a gel that
bonds to the sowing surface, localizing the seedling to
grow at that point. The invent~on uses a water soluble
polymer, a water retentive polymer in combination with
bulking material, and other components described below to
achieve the desired protection.
The matrix permits the passage of oxygen to the
; seedling and can include nutrients, dyes, fertilizers,
~ and fungicides. The matrix of the invention can be
; 20 shaped to accommodate a seed of any size for forestry,
; agronomic or horticultural purposes. It is envisioned
that Applicants' invention will be used to replant stands
- of longleaf pine, slash pine, white pine, red pine, jack
pine, spruce, and other commercial tree crops.
Factors influencing the way in which Applicant~'
invention is used in the forestry industry include the
amount and type of rainfall received in a planting area.
Where rainfall varies from very intense to long drought
periods as in the southeastern United States, insertion
in a small hole formed in the 80il is preferable. Where
rainfall is less intense and more consistent as in the
-~ northwestern United States, England and Canada, aerial
-~ disper~ion would achieve the greatest cost savings in
- labor and ti~e.
Additional important uses for the matrix are with
commercial vegetable crops, in the commercial greenhouse
trade, and by the significant number of amateur
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5 13287~4
gardeners. In particular, i~ is envisioned that the
potted house plant market will obtain great benefit from
the water retentive properties of the matrix when used as
a replacement for conventional potting soil. Used as a
~- 5 potting medium, the matrix will not need watering for up
to a full month after initial watering. It releases
water over time on an as needed basis helping to prevent
over or under watering of the plant.
The components of Applicants~ invention include:
A. Hydrophilic Fibrous Bulking Agent
: A hydrophilic fibrous bulking agent forms the
; majority (55 to 80% by weight) of the total matrix.
" Examples of the bulking agent include peat, cotton,
r mineral wool, paper pulp, wool and hair. The grind size
of the bulking agent i8 important to the matrix retaining
its structural integrity even when wet. In its preferred
form, the bulking agent is peat that can pass through a
1/8" scre~n.
B. Water S41uble Binder Material
` 20 Substantially fully-hydrolyzed (90-100%) polyvinyl
alcohol (PVA~ is the preferred water soluble binder
material. The invention requires that whatever water
-~ soluble binder material used is soluble in hot water to
- solution impregnate the peat or other bulking material,
but i~ largely insoluble in cold water to maintain
binding of the matrix under field conditions. Cold water
soluble PVA would be unacceptable since it would leach
from the matrix when wet. The PVA i8 chosen from a broad
molecular weight range, so that when wet the PVA
continues to bind the matrix together. A number average
for the molecular weight of the water soluble binder i~
approximately 10,000 to 150,000. The PVA is used in an
amount of 5 to 40% by dry weight of the total matrix
depending on expected climatic conditions. Applicants
used approximately 12% PVA (Elvanol~ 7130, E.I. du Pont
de Nemour6 and Company). The particular PVA used has a
molecular weight of approximately 50,000. Additional
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13287~
water soluble binders which can be used in the invention
include polyvinyl acetate and polyacrylates.
C. Non-ionic Surfactant
Non-ionic surfactant or emulsifier wets the dry
hydrophilic bulking agent and allows it to blend with
substantially fully-hydrolyzed (PVA) in solution. The
surfactant decreases surface tension otherwise preventing
water take up and thus increases the rate at which the
bulking agent absorbs water. Surfactants include
polyoxypropylene-polyoxyethylene block co-polymers:
alkanol amides, betamol derivatives; block copolymers
comprising a series of condensates of ethylene oxide with
hydrophobic bases formed by condensing propylene oxide
with proylene glycol; ethyoxylated compounds comprising
`~ 15 alcohols, alkyl phenols, amines and amides, alkylphenol
ethoxylates, fatty alcohol polyglycol ethers, oxo-alcohol
polyethyleneglycol ethers, alkylphenol-ethoxylate~, fatty
or oxo-alcohol polyethylene glycol ethers, and
~- hydrophilic and hydrophobic block copolymers.
Applicant'6 preferred non-ionic surfactant is
polyoxypropylene-polyoxyethylene block copolymer
(Pluronic L-92, BASF) in an amount of 0.001 to 3.5% by
dry weight of the total matrix.
` D. Noisture Content
The materials, including the bulking agent, the
water coluble polymer, and the non-ionic surfactant, are
blended with a roller drum and dried to approximately lO
to 25% moisture content in a 95C air circulating oven.
Moisture content of the matrix at the point of production
is a critical feature to maintain the relative qualities
of the water soluble material and the water-retentive
polymer described below. The amount of water needed to
trigger the activation of the water-retentive polymer to
sufficiently allow encapsulation was surprisingly small.
The moisture activates the binding agent to form the
matrix networ~ which assists in maintaining the
structural integrity of the matrix during transport and
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- 13287~4
handling. It is understood that climatic conditions
after production may affect the moisture content and
appropriate packaging may be required to prevent this
while the invention is in storage or transit.
E. Water-Retentive Polymer
,.~
Water-retentive polymers, also called superabsorbing
polymers or SAP's, are hydrophobic materials which can
~- absorb fluid and retain it under pressure without
dissolution in the fluid being absorbed. The materials
used are generally all synthesized by one of two routes.
In the fir6t, a water soluble polymer is cross-linked so
that it can swell between cros~-links but not dissolve.
;~ In the second, a water-soluble monomer is co-polymerized
with a water-insoluble monomer into blocks. The earliest
lS superabsorbent materials were saponified starch graft
polyacrylonitrile copolymer~. Synthetic superabsorbers
include polyacrylic acid, polymaleic anhydride-vinyl
monomer superabsorbents, starch-polyacrylic acid grafts,
polyacrylonitrile based polymers, cross-linked
~ 20 polyacrylamide, cross-linked sulfonated polystyrene,
`- cross-linked n-vinyl pyrrolidone or vinyl pyrrolidone-
- acrylamide copolymer, and polyvinyl alcohol
superabsorbents.
These polymers absorb many times their own weight in
aqueous fluid. The water retentive polymer chosen for
seed encapsulation should have a water absorbtivity of
between 50 and 600 times its weight. At such absorption
levels, the entire composition upon exposure to rainfall
is converted to a wet, gas-permeable gel which protects
and bonds said seed to the ground during germination.
Additional candidate~ for the water-retentive
polymer include sodium propionate-acrylamide, poly(vinyl
pyridine~, pclyethylene imine, polyphosphates,
poly(ethylene oxide), vinyl alcohol copolymer with
acrylamide, and vinyl alcohol copolymer with acrylic acid
acrylate.
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-- 132~744
The preferred water-retentive polymer used by
Applicants i8 1 to 25% by dry weight of potassium
acrylate acrylamide copolymer, preferably in an amount of
13 to 16% by dry weight of the matrix. The material i8
commercially available under the trade mark "Viterra"
from the Nepera Chemical Company.
For~,ation of Compressed Matrix Product
The matrix was compressed at room temperature to
form a seed encapsulating product. The matrix may be
compressed while containing the seed, but this re,~uires a
lower pressure to prevent injury to the seed.
Alternatively, the matrix may be pressed at high
- pressures (approximately 7500 psi) before the seed is
~ inserted into the matrix unit. The size of the cavity to
- 15 hold the seed is determined by the size of the particular
seed type used. Once the ,6eed is placed in the cavity,
;~ the cavity opening i8 plugged with a suitable material
that will remain in place once dried and that i~ not
toxic to the seed or germinating plant. For example,
Applicants used a paste composed of 50% by dry weight dry
peat and 50% by dry weight of an a,~ueous solution
~` containing 11.25% by dry weight PVA (Elvanol~ 7130, E.I.
du Pont de Nemours and Company) and 0.125% by dry weight
non-ionic surfactant (Pluronic L-92, BASF). Other
material may be used to plug the cavity including
silicate clays.
Functioning of the Encapsulated Seed
~ When the blended material is wetted after seeding by
: hand, by machine, or by air, it becomes gel-like,
expands, and bonds to the soil localizing the ,6eedling's
growth at the point the seed capsule is deposited.
Approximately one inch of rain is re,~uired to activate
the preferred capsule matrix: however, water re~uirements
- can be varied in light of local climate condition,s, seed
re,~uirements, and re~ulting proportions of matrix
components. f~he resulting gel-like ~,tructure permits the
exchange of oxygen and the retention of water which are
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13287~
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essential for the germination of the seeds. It also
; forms a mechanical barrier to predators. In addition,
the encapsulating process per~its the optional inclusion
of nutrients, fertilizers and fungicides selected to
address local conditions. Applicants have added
commercial fungicides such as Benlate~ at levels to 5000
ppm, Ridamil~ at levels to 50 ppm, and Thiaram~ at levels
up to 25 ppm to the matrix without toxic effect to the
seeds.
Precise ratios of ingredients are important to
obtain the most advantagesus characteristics of the
matrix. The particular use made of the matrix and local
growing conditions will dictate the ratios chosen. Por
instance, it is essential that the matrix, when wetted,
holds sufficient water to supply the needs of the
- germinating seeds, bedding plant, or house plant, but not
hold so much to subject the seed or plant to a
deleterious a~ount of water. The combination of
component characteristics in the matrix yield a product
that has qualities of performance, convenience and cost-
effectiveness.
EXAMPLES
EXAMPLE 1. Preparation of Encapsulating Matrix.
` Commercial peat moss was dried in an air oven to
less than 1% water content, ground in a Wiley mill, and
screened through a 1/8" holed screen. Two hundred grams
of a distilled water solution containing 15.62 g of
poly(vinyl alcohol), (Elvanol~7130, E.I. du Pont de
Nemours), and 0.260g of surfactant, polyoxypropylene-
polyoxyethylene block copolymer (Pluronic~L-92, ~ASF),
were added to 100g of the above dried peat moss and hand
~ blended in a plastic bag. The blend was then placed in
- an 85 C oven and dried to a moisture content of between
10 and 25%, as ascertained using an Ohaus Moisture
Analyser, Model 6010PC. The moisture content was
ascertained but not recorded, since subsequent handling
- and storage before seed encapsulation resulted in minor
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132874~
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changes in the water content. The resulting material was
then dry blended in a bag with 14.32 g of the water
-~ retentive pol~mer, potassium acrylate acrylamide
copolymer (Viterra~, Nepera Chemical Co.). The resulting
blend thus had the following dry weight percentages of
each component of the total non-aqueous ingredients, by
calculation: 12% poly(vinyl alcohol) (Elvanol~ 7130, E.I.
du Pont de Nemours), 0.2% surfactant (Pluronic~ L-92,
BASF), 11.0% water retentive polymer (Viterra~, Nepera
Chemical Company) and 76.8~ peat.
EXAMPLES 2 to 7
Using the same procedure as in EXAMPLE 1,
~; compositions were made varying the amounts of ingredients
` added to lOOg of dried peat to give the following
calculated weight by percent compositions (on a dry
basis, as in EXAMPLE 1):
:~ Example ~ Poly(vinyl alc.) Pluron~c L-92 Vit~rra/grade Peat
2 1696 0.2%11/360E 72.89
3 24 0.2 11/360E 64.8
4 24 0.2 5/360E 70.8
24 0.2 16/360E 59.8
6 18 0.2 11/360E 70.8
7 14 0.2 11/360E 74.8
EXAMPLES 8 to 11
These examples use the same procedure as in Example
1, except that in Examples 9 and 11, a small amount of
- 30 methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate
fungicide (Benlate~, E.I. du Pont de Nemours) was added
at the same time the aqueous solution was added to the
- dried peat moss. The following compositions were
prepared. Quantities refer to weight percent of total
non-aqueous ingredients:
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Example ~ Poly(vin. alc) Pluronic L-92 Vit~rra/ Peat Fungicide
grade
8 12 0.27.5/360E 74.8 0
+7.5/375
9 12 0.27.5/360E 74.55.25
: +7.5/375
18 0.211/360E 70.8 0
- 11 18 0.211/360E 70.3 .5
Viterra~ grade 360E ha~ an average grind size of 0.3 mm.
Viterra~ grade 375 has an average grind size of 1 mm.
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EXAMPLES 12 to 19 and EXAMPLE 20. Encapsulation,
~ Greenhouse Germination, and Control.
i In Table I, the matrix number refers to the polymer
r 20 from the corresponding matrix preparation examples above.
Table I also indicates the encapsulation procedure and
~ gives the results of germination studies. The
.,'',J~ encapsulation method varied depending on whether the seed
was inserted within the matrix after (Method A) or before
~, 25 (Method B) pressing. In addition, the germination
conditions varied. The germination methods (Methods A, B
and Control) are described below.
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; TA~LE
. -~ LOBLOLLY SEED ENCA~5nLAnON A~l) GE3RMnNAnC~N SllUI)I~
.,
. ~ NO. OF ll~;r IqRE~iSING WE~rllNG % GE3RMlrlAllON (DAl~S)
E3CAJuCPllE # MAll~CY # S~PEC~fEr~S~EiT~iQD M~3C~al2 7 L 21 2
.,. 10
.2 12 1 8 A A O 13 25 38
: . ~ 8 A A 0 25 50 50
. 8 A B 0 25 38 100
~: 8 A B 13 25 25 75
13 2 8 A B 0 13 63 75
^ 8 A B 0 13 ~3 7s
8 A A 0 13 2s 63
8 A A 0 2s 75 88
. 14 3 8 A B 0 50 63 88
8 A B 0 0 38 75
8 A A 0 0 2s 88
8 A A 0 2s so 6a
:~ 15 4 8 A B 0 38 63 75
8 A 8 0 2s so 75
8 A A 0 75 75 75
16 5 8 A B 0 25 38 38
.~. 8 A B 0 0 38 50
, 8 A A 0 13 25 38
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., 35 17 6 8 8 B 0 13 ~3 13
8 B B 0 13 13 13
;, 8 B A 0 S3 63 75
. 8 B A 0 75 75 ;5
18 6 8 C B 0 25 2s 2s
8 C 8 0 13 13 13
8 C A 0 50 50 so
8 C A 0 13 25 3
` . 19 7 8 8 B 0 25 63 75
8 B B 0 3R 50 63
8 B A 13 63 ~3 63
,
(Bare S~##l ~ B 33 41 59 6~
Cont~]) 48 - A 31 63 75 79
. 48 - B 0 38 65 85
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Encapsulation:
Method A. About 4g of matrix was pressed in a
conventional platten type compression molding machine at
room temperature, using a pressure of 7500 psi per
capsule. A cylindrical mold cavity was used resulting in
capsule dimensions of 0.5 in. deep and 0.75 in. diameter.
The mold had a concentric stud resulting in a hole in the
capsule 5/16 in. deep with a diameter of 3/16 in. The
seed was placed in the hole, which was then plugged with
ground up peat moistened with surfactant.
Method B. About 2g of peat was placed in the mold
and a seed carefully placed as centrally as possible in
the mold. About 2 more g of peat was then added to the
i mold. The peat and seed were then compressed at room
temperature with a pressure of only 263 psi, in order to
minimize damage to the seed during encapsulation.
Method C. The same procedure as that described in
` method B was used, except that the pressure was only 188
psi .
Germination:
Method A. Several capsules were wetted in the
numbers of specimens indicated by the Table I and placed
in a pan on the soil surface and brought to field
` capacity. "Field capacity" refers to the saturation
point or the amount of water that the soil will hold at
equilibrium. The pans were then covered with a clear
- acrylic sheet to maintain field capacity, providing
sufficient moisture for encapsulated seeds to germinate.
The pans were then placed in a greenhouse and maintained
at 65-75F.
Method B. Several capsules were wetted and placed
in a pan on the soil surface. The pans were not covered
but were subjected to 0.5 inches of simulated rainfall
every other day. This provided sufficient moisture to
germinate the encapsulated seeds.
Control method. Bare seeds were placed directly on
the soil surface and their germination time recorded.
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132874~
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Germination data in the accompanying Tables include
the number of seeds germinated after the indicated number
i of days. Values are given in percentages. Thus 1 out of
8 is shown as 13~; 3 out of 8 as 38%; etc.
The Examples show that capsules allow seeds to grow
as well as seeds planted directly. That is to say, the
capsules do not have a phytotoxic effect on the seeds.
The data suggest that there may be some damage to the
seed resulting in slightly reduced germination when the
seed is in place before pressing the capsule. The
greenhouse studies described above do not show
superiority of the capsule over bare seeds, since this
~; would only be expected under field conditions where
predation and other adverse conditions would be expected
to adversely affect bare seeds. Such field test are
described below.
EXAMPLES 21, 22, and Control EXAMPLE 23.
These examples used the encapsulating Method A as
described above. In Table II below, the initial number
refers to the matrix of the corresponding matrix
preparation examples. The capsules were placed in holes
1.5 inches in diameter and 1.25 inches deep. Germination
xi~ studies were carried out in the fall in Buna, Texas.
Data are shown in Table II giving number of specimens and
germination after 28 days. Rainfall measured during the
period is given. These tests show the superiority in
percent germination of the capsules over bare seeds under
real growing conditions. They also indicate that the
presence of a fungicide further increases the germination
rate.
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TABLE II
FALL_FIELD TEST DATA
(Buna, Texas)
%GERNINATION
EXAMPLE ~ M~TRIX ~ NO . OF SPECIMENS (AFTER 28 DAYS )
21 8 50 56
- ~ 22 9 50 66
: 23 - 50 36
( Bare Seed Control )
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Rainfall during 28 day period = 1.55 inches
;~ 7th day = 1.10 inches
9th day = 0.25 inches
~`~ 25 12th day = 0.10 inches
17th day = 0.10 inches
EXAMPLES 24 and Contrcl EXAMPLE 25.
~; 30 Matrix 6 was used in this EXAMPLE 24. This Example
:-,
~ used the encapsulating method A described above. The
,, data shown in Table III were obtained from greenhouse
- tests. Seeds or capsules were placed on the surface of a
sandy loam soil contained in pans with
- 35 holes drilled in the bottom. The soil was wetted to
field capacity initially. The pans were then placed on
~ rubber sponge pads that were kept saturated with water.
;~ The greenhouse was kept between 65 and 75 deg F and a
relative humidity of 45 to 70%.
These tests were designed to show the effects where
- only a limited amount of water was present, or the
conditions placed the seeds-'under stress.' Once again,
the results æXlown in Table III, indicate the clear
advantage of lencapsulation.
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TABLE III
GERMINATION DATA FOR LOBLOLLY PINE SEEDS
(Stress Test)
GERMINATION
(DAYS)
EXAMPLE # MATRIX tNO. OF SPECIMENS 7 14 21 28
24 6 ~2 0 32 57 64
.~ 24 0 25 45 63
128 4 30 50 67
: 25 (Bare Seed
Control) 72 0 25 25 25
24 O 8 29 38
24 0 21 25 33
~ 15 EXAMPLES 26, 27 and 28
s~ These Examples used the encapsulating Method A
`~ described above. In Table IV, the intitial number refers
to the matrix of the corresponding matrix preparation
~;, examples. The capsules were placed on the soil surface.
Germination studies were carried out in the spring in
Buna, Texas. Data are shown in Table IV giving the
~- number of specimens and germination after 28 days. Total
rainfall measured during the period is given. These
tests show the superiority in percent germination of the
capsules over bare seeds under real growing conditions.
~ They also indicate that the presence of a fungicide
- further increases the germination rate.
TABLE IV
Spring Field Test Data
; (Buna, Texas)
-: ~ GERMINATION
35EXAMPLE t MATRIX tNO OF SPECIMENS ~AFTER 2~ DAYS~
44
(wLthout
Benlate~)
27 11 50 58
(~ith
, Benlate~)
28 50 41
- 45(Bare Seed
Control)
Rainfall during 28 day period - 8.46 inches
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17 13287~
EX~MPLE 12
Applicants compressed the following matrix
- composition into 2" X 3/8" chip-like wafers with 7500
psi:
12% by dry weight PVA (Elvanol~ 7130, E.I. du Pont
de Nemours and Company)
15% by dry weight water retentive polymer
(Viterra~, Nepera Chemical Company), 7.5% 360E
grade/7.5% 375 grade
-; 10 .35% non-ionic surfactant (Pluronic~ L-92, BASF)
72.65~ hydrophilic bulking agent (peat)
.
Sufficient water is added to trigger the water
retentive polymer enough to bind the wafer together
during production.
The matrix wafers were then moistened to fully
activate the water retentive polymer and the resulting
matrix used as potting soil in which to plant house
plants. The size of the wafer was determined by
reference to the standard size flower pot the matrix
would expand to fill. Preliminary growing trials were
run with squash, watermelon, cantaloupe, bell pepper and
; okra plants over a two month period. No deleterious
effects were noted from use of the matrix and water
retention of the matrix was considered a convenience and
advantage.
A variety of house plants were potted in the matrix
~ including Pathos, Aglaonema, "China Doll", Rex Begonia,
- Calathea, Draconia, Diffenbachia, Boston Fern, Aloe,
Croton, and "Peace Lily". No deleterious effects from
use of the matrix were noted. Comparable specimens of
Pathos, Aglaonema, "China Doll", and Rex Begonia were
planted in the matrix and in conventional potting soil.
Each was wate,~ed once to saturation at the outset of the
trial period imd like species were compared after 20 days
(Pathos, Aglaonema) and 10 days ~"China Doll", Rex
Begonia~. All of the house plants planted in Applicants'
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matrix showed a more healthy appearance than those
planted in conventional potting soil. Evidence of
advantageous effects included glossier leaves, no
wilting, more growth, and no browning of leaves.
Applicants believe that the matrix's ability to release
water on an as-needed basis accounts for the superior
results of these trials.
It will be apparent that the instant specification
and the examples are set forth by way of illustration and
lo not limitation, and that various modifications and
changes may be made without departing from the spirit and
scope of the present invention.
7~
".'~
