Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
4~
TITLE BA-8208-~
DRY COMPACTIBhE, SWELLABLE HERBICIDAL COM-
POSITIONS AND PELLETS PRODUCED THEREFROM
.
BACKGROUND OF THE INVENTION
This invention relates to herbicidal com~osi-
tions for controlling undesirable brush in rangelands
and woodlands and, more particularly, to herbicidal
compositions which are dry-compacted lnto swellable
pellets having improved properties for aerial applica-
tion and US2 in low-rainfall areas.
Undesirable weeds and thorny brush growth such
as mesquite, huisache, yaupon, McCartney rose and the
like infest millions of acres of rangeland. Once
heavily infested, such rangelands are no longer suited
for livestock grazing.
Broad-spectrum herbicides, which are normally
applied to infested acreage with aerial or ground
sprays, or by a dry granule broadcast method, destroy
not only the undesirable brush, but also much needed
grasses and other ground cover. Although selective
herbicides can be used to avoid injury to ground cover,
the high concentrations of active ingredient which are
needed to destroy the hardy brush varieties can make
the cost of selective herbicides prohibitive.
In woodlands, particularly pine woodlands
which are "farmed" to produce trees for the pulp ând
paper industry, brush growth can retard the develop
ment of young trees and may increase the planting-to-
harvesting cycle by as much as eight years. Broadcast
applications of conventional herbicide formulations at
rates high enough to control the undesirable brush can
5 kill or severely damage the young trees.
The compositions of this invention are aimed
typically at woodland and brush areas which are arid
and have low rainfall. Any herbicide which is to be
useful for this type of area must require very
10 little water to make the matlsrial active in the soil.
Furthermore, economy o~ application, where large areas
and difficult terrain are involved, favors the use of
airplanes.
With certain herbicides -- such as the ones
15 used in the compositions of this invention -- selec-
tion between the large brush that must be controlled
vs. the seedling trees or grass for grazing whose
growth the treatment should promote, can be obtained
by applying the herb~cide as large pellets or bri-
20 quettes on a grid pattern, for example on a 1-3 meter
grid. As the herbicide is moving downward from the
relatively few loci of the grid, the large root
systems of the brush can pick up a lethal dose of
herbicide while in the remaining areas the grass or
25 the seedling trees grow without damage.
This combination of application requirements
can only be met with large pellets or balls which
have ~ery special physical properties. The handling,
shipment, storage and use of such material requires
30 that these pellets be hard, crush and impact resis-
tant, and unaffected by high relative humidity,
while, at the same time, after application, the pel-
lets must swell and disintegrate after only small
amounts of rainfall to release the active herbicide.
Thus, there is need for a composition hav-
ing a critical set of properties which are in part
contradictory and are difficult to attain. Further-
. , , :
more, it is important to produce these compositions,
i.e. these pellets and balls, economically. Hence,
expensive wet extrusion and drying processes should
be avoided in favor of dry-compaction or briquetting.
SUMMARY OF THE INVENTION
The present invent:ion provides a dry-compac-
tible composition consisting essentially of about 5 to
25% by weight of a herbicide selected from the group
consisting of 5-bromo~3-sec-butyl-6-methyluracil
(hereinafter bromacil), [3-(3,4-dichlorophenyl)~
dimethylurea] (hereinafter diuron), bromacil-diuron
complex, 3-cyclohexyl-6-(dimethylamino)-1-methyl~s-
triazine-2,4 (lH, 3H)-dione (hereinafter Velpar~ weed
killer), karbutilate, tebuthiuron and N-[(4,6-dimethoxy-
1,3,5-triazin-2-yl)aminocarbonyl] benzenesulfonamid
and mixtures thereof, 20 to 60% by weight of swelling
bentonite, 5 to 15% by weight of anhydrous sodium
sulfate, 10 to 25% by weight of urea, 2 to 10% by
weight of a polyethyle~le glycol with a weight-average
molecular weight ranging from 200 to 600, 0-5% of a die
release agent selected from the group consisting of
stearic acid, calcium stearate or magnesium stearate,
1 to 12% by weight of water and 0 to 30% of an inert
diluent.
The term "bromacil-diuron complex" as used
herein means the 1:1 molar complex of the two compon-
ents as described in U.S. Patent 3 914 230.
Pellets prepared by dry compacting these
compositions are particularly useful for aerial appli-
cation to woodlands and rangelands for controlling
undesirable brush. The pellets of this invention com
bine the advantages that they can be produced by dry
compaction (e.g., the composition does not require a
wet extrusion step followed by heating and/or drying),
are impact- and crush-resistant while dry, and are
.
highly resistant to disintegration in high-humidity
atmospheres. Once applied, these pellets will swell
and disintegrate rapidly and hence will release the
active herbicide when exposed to only a small amount
5 of liquid water and will not re-harden when drledO
DET~ILED DE5CRIPTION OE' THE INVENTION
Improved physical properties can be achieved
in herbicide compositions used for controlling brush
on rangelands and woodland by dry-compacting a compos1-
10 tion consisting essentially of about 5 to 25~ byweight of active ingredient, about 20 to 60~ by weight
of a swelling bentonite, about 5 to 15~ by weight of
anhydrous sodium sul~ate, about 10 to 25% by weight of
urea, about 2 to 10~ by weight of a polyethylene glycol
15 with a weight-average molecular weight ranging from
200 to 600, about O to 5% by weight of a die release
agent, about 1 to 12% by weight of water and from O
to 30% by weight of an inert diluent into pellets or
balls having a density in the range of about 0.5 to
2~ 1.75 grams/milliliter and a volume in the ran~e of
about 0.75 to 2.0 cubic centimeters. The term"pel-
let" is used herein to mean a shaped body such as a
briquette, bolus, ball or any other suitable shape.
The phrase "consisting essentially of" is
notintended to limit the claims so as to exclude other
ingredients when the specification clearly indicates
other constituents may be present. The phrase does
exclude ingredients which would affect the basic and
novel characteristics of the invention defined by the
3~ claims.
The pellets of this composition have a cri-
tical balance of physical properties which is important
in the control of undesirable brush in arid regions
used for grazing or forestation. The process and com-
position combine to yield a pellet which is hard,crush- and impact- resistant, and unaffected by high
relative humidity in storage. Yet, after application,
.
'
~9~4~
the pellet can swell and disintegrate upon contact with
only a small amount of liquid water (rainfall) to acti-
vate and release the herbicidal acti~e ingredient.
Generally, the pellets of this invention are
5 applied by aerial means in a low-density pattern over
the acreage to be treated. Spacing the pellets on the
average about 1 to 3 meters apart provides for optimum
distribution of active ingredient. Other grid patterns
and pellet spacing may also be used.
The compositions of this invention will typi-
cally contain the following essential ingredients:
(1) an active ingredien~ having the desired biological
activity; (2) a swelling bentonite to accomplish struc-
tural disintegration of the pellet on contact with
liquid water; (3) anhydrous sodium sulfate to prevent
the pellet from rebonding if drying should occur after
the pellet has been initially exposed -to liquid water;
(4) an inert ~iluent to adjust the weight and composi-
tion of the pellet and a combination of (5) urea; (6)
polyethylene glycol having a weight-average molecular
weight of 200-600; and (7) water below about 12~ by
weight o~ the total composition to serve as plasti-
cizer, binder and lubricant during dry pressing.
As used herein the term "swelling bentonite"
means absorptive clays generally described as montmor-
illonites and capable of expanding their lattice
structure upon the absorption of water. Such clays
are described by R. K. Iler; The Colloidal Chemistry
of Silica and Silicates, pp. 191-198, Cornell Uni-
versity Press, Ithica, ~ew York, 1955. Examples ofcommercially available swelling bentonites are:
Volclay~, Wy-O-Gel~, and other Wyoming bentonites.
The active compounds useful in this invention
are herbicides selected from the group consisting of
bromacil, d.iuron, bromacil-diuron complex, mixtures of
bromacil-diuron complex with bromacil or diuron,
Velpar~ weed killer, karbutilate, tebuthiuron, and
'.
'~ '. ' , . .
v ~ ~
N-[4,6-dimethoxy-1,3,5 triazine 2-yl)-aminocarbonyl]ben-
zene sulfonamide, and combinations o~ these.
The ingredients are dry blended in any suit-
able blending apparatus in the desired proportions.
5 The blended ingredients may also be ground in a
hammer-mill, ball mill, rod mill or other suitable
grinding equipment. The composition is reblended ater
milling to insure uniformity. Dry compackiny i5 accom-
plished by conven~io~al methods to form ~he water
10 swellable pellets. Briquetting and pill pressing are
particularly suitable methods for dry compacting these
compositions. In the case o~ some mixtures of ingre-
dients (depending upon the properties o~ the active
herbicidal chemical, the particle size range and the
15 proportions of the ingredients) deaerating the ground
and blended composition may be necessary prior to the
dry compacting operation in order to prepare a pellet
with the required crushing strength and impact resis-
tance. Deaerating can be accomplished economically by
20 precompacting the composition by passing the mixture
through: (1) "squeeze" rolls; or ~2) a deaerating ~com-
pacting) screw feeder immediately prior to dry com-
pacting~ The bulk density of deaerated mixtures can
be increased up to two to three times that of the
25 aerated mixture. The deaerated mixtures can be com-
pacted by roll briquetting at much higher rates than
the corresponding aerated mixtures. In order to pre-
vent sticking of the compacted material in the dry-
forming die a small amount of a die release agent may
30 be added to the composition. Suitable die release
agents are stearic acid, calcium stearate or magnesium
stearate. The die release agent is blended into and
ground with the other ingredients.
Dry processing prevents premature swelling
35 of the bentonite and obviates the need for any drying
step in preparing the pellets. It should be noted
that bentonites swell when initially exposed to small
C39~
amounts of liquid water for about 5 to 120 minutes.
If dried under mild conditions such as might exist in
rangelands, only excess water is removed by evapora-
tion. The water that produces the swelling by absorp-
tion into the lattice of the bentonite is not evapor-
ated. Therefore, swelling generally occurs only once.
However, wet bentonite will dry in time and become
hard, resulting in a reduced surface area from which
the active ingredient may only be slowly leached by
successive wetting. To prevent the bentonite from
hardening, anhydrous sodium sulfate is incorporated
into the composition. Anhydrous sodium sulfate is
used because it is capable of forming stable hydrates
from 0.5 moles of water up to 10 moles of water per
lS mole of anhydrous sait.
The binder material for the composition of
this invention includes urea because of its water
solubility and biological considerations. The presence
of small amounts of water in the composition, prefer-
ably from about 1 to 12% by weight, more preferablyfrom about 4-8% by weight, acts as a plasticizer for
the urea and aids the b~nding process during dry ccmpaction.
Water-insoluble and slcwly soluble binders, such as s~dium
silicate, retain their binding properties for extended
periods in the presence of liquid water and would in-
hibit the swelling of the bentonite. Other water
soluble binders such as sugar, polyvinyl alcohol,
and polyvinyl pyrollidone generally require more than
12~ by weight of water for effective binding. Their
rates of solubility are also much less than urea so
that they do not cooperate as efficiently with the
; other ingredients of the compacted composition to
allow for swelling and as rapid a release of the
active ingredient.
The polyethylene glycol operates within the
composition as a liquid reservoir together with the
water. Polyethylene glycol also protects against
; 7
~L~9~399~
water migration among the ingredients of the composi-
tion which could result from temperature changes dur-
ing storage. Thus, premature swelling and crumbling
of the pellets is prevented. The pellets of this
S invention may be stored in sealed containers for up
to about two years without any significant or dele~
terious change in chemical or physical properties.
The polyethylene glycol should have from
about 200 to 600 weight average molecular weight.
Lower molecular weight glycols, for example ethylene
glycol and diethylene glycol, exhibit relatively high
vapor pressures and tend to volatilize at high ambient
temperatures. High molecular weight glycols, normally
liquid at ambient temperatures, are generally viscous
and difficult to distribute uniformly during prepara-
tion of the composition.
Inert diluents may be incorporated into the
composition up to about 30% by weight of the dry com-
pacted product to adjust the weight of the pellet.
Preferred diluents include, but are not limited to,
inert clays such as non-swelling bentonites, sub-ben-
tonites (Panther Creek clay), attapulgites (Attaclay~),
kaolinites (Barden clay) and diatomaceous earth.
Ground or aerial application techniques can
be used to distribute the pellets of this invention
in the desired pattern over the area to be treated.
Where large or remote surface areas are to be treated,
aerial application is the most economical and prefer-
red method. The pellets are released from an air-
craft at a rate which will achiave ~he desired gridspacing and, hence, distrihution of active ingredient,
when the pellets come to rest on the ground.
By the term grid spacing or grid pattern is
meant an average spacing of pellets over a hectare of
treated area. For example, to apply 1.12 kg o~ active
ingredient in a grid pattern of one hectare using pel-
lets containing 15~ by weight of active herbicidal
.
99~0
chemical requires 2990 pellets t7.5 kg) applled in a
square grid pattern with an average spacing between
adjacent pellets of 1.8 meters. Precise spacing can-
not be absolutely maintained between each pair o
pellets due to effects of external forces such as air
turbulence, contact with canopy foliage, deflection by
branches and rebounding or bouncing of some pellets
which occasionally strike exposed hard ground or other
firm objects on the ground surface. However, these
slight disturbances in the precise grid pattern de-
sired do not affect the overall biological performance
of the pellets under field conditions.
At the ground location of each pellet any
destruction of ground cover by released herbicide is
generally confined to a circular area no larger than
about 30 centimeters in diameter. The area of the
denuded spots is de-termined by the soil conditions
controlling the ground penetration rate of the active
ingredient which is being released from the pellet,
the amount and rate of rainfall, and the particular
active ingredient and its release rate ~rom the
pellet.
A grid distribution of the pellets creates
generally conical "columns" of herbicide within the
soil with the apex at the surface location of the
pellets. When released from the pellet by small
amounts of liquid water, such as from dew or rain,
the active ingredient penetrates downwardly through
the soil. This type of distribution and penetration
allows the active ingredient to reach the roots of
hardy brush species and avoid contact with the
shallow rooted, more desirable grasses and ground
cover. Only a small portion of a plant or tree root
system need be exposed to the herbicide to retard or
eliminate it.
The swelling and crumbling of the pellets of
this invention when contacted with small amounts of
9g4~
liquid water not only permits the active ingredient to
be released quickly from the formulation, but also
destroys the physical structure of the pellet. Thus,
small animals such as rabbits and rnice are much less
likely to find a pellet intact and be exposed to the
active ingredient. The active herbicide is quickly
released to the soil from the pellet when swelling
occurs, and small animal population is protected.
Usual application techniques employ either
mechanical "slingexs" or pnelLmatic devices which
distribute the pellets ov~r swaths or bands up to
about 15 meters wide. The term "slinger" is used to
define a rapidly rotating disk having radial spaced
baffles. The pellets are dropped onto the "slinger"
at a controlled rate, are struck by the baffles and
impelled a given distance from the "slinger" to achieve
the desired swath width.
Of the pneumatic applicators, one is a "fish
tail" type used for aerial seeding and fertilizer
applications from ~ixed wing aircr~ft. The herbicide
pellets are dropped into a ram air section having an
air stream velocity of about 40 to ~5 meters/second
and forced by the air stream against baffles in the
"fish tail" discharging area. A second type of pneu-
matic applicator is adapted for use with helicopters.It employs a blower to provide a high velocity air
stream which ejects the pellets in a swath pattern
from a duct system into which the pellets are fed.
It will be appreciated by those familiar
with application techniques that the pellets are sub-
ject to a multiciplicity of forces during application.
As the pellets fall to the ground they strike the leaf
canopies and branches of taller trees and brush. They
are also affected by the nature and velocity of any
crosswinds as they fall.
The pellets of this invention provide the
desired combination of physical properties and
exhibit high crushing and impact strength to resist
damage from shipping, handling and the ~orces associ-
ated with application. Because of their improved
physical properties, the pellets of this invention
can be better controlled during aerial application
to achieve the desired grid pattern. The pellets are
dense enough to resist deflection by crosswinds and
the leaves of brush and tree canopies.
Crushing strength is determined by first dry-
compacting the desired formulation, after blending and
grinding, to obtain a cylindrical sample pellet 16 mm
in diameter by about 9 to 11 mm long. Compacting is
accomplished by applying 1400-1450 kg/cm2 pressure to
a piston which compacts the loose formulation in a
cylindrical die. After compaction, the pellet is
placed horizontally between two horizontal parallel
steel plates and the plates are loaded until crushing
occurs. Pellets of this invention resist crushing
with loads less than about 7500 grams or 3.7 kg/cm2.
Impact resistance is measured by dropping a
sample pellet as compacted above onto a smooth, hard
horizontal surface such as concrete or steel from a
height of 3 meters. Pellets of this invention nor-
mally resist breakage for 5 drops.
The reaction of a sample pellet to wetting
with liquid water and subsequent drying is determined
by placing the pellet into a covered Petri dish and
applying 0.5 ml (5 drops) of water thereto. Swelling
and crumbling is observed during the first 2 to 5
hours. The pellets of this invention will crack
immediately after wetting and swell to about 2 to 3
times their original volume during the observation
period. The cover is then removed and the pellets
are allowed to dry at about 23C and between about
25 to 60% R.M. When dried the pellets of this inven-
tion do not rebond but remain crumbled.
Apparent density of the pellets is measured
~, 11
~L~9~ 4~
12
by mercury displacement. The density of the pellets
of this invention is such that mercury will not pene-
trate the pores thereof. Pellets of this invention
exhibit an apparent density of about 1 g/ml or yreater.
Composition ranges of the pellets of this
invention are given in Table 1:
TABLE ]
Composition ~ by
Ingredient Weight
Active Herbicidal Chemical 5-25
Swelling Bentonite 20-60
Anhydrous Sodium Sulfate 5-15
Urea10-25
Polyethylene Glycol
(200-600 Wt. Average Mol. Wt.) 2-10
Total Water 1-12
Die Release Agent 0-5
Inert Diluent 0-30
More preferred composition ranges are shown
in Table 2:
2~ TABLE 2
Composition Range,
Ingredient % by Weight
Active Herbicidal Chemical 8-15
SwelIing Bentonite 30-50
Anhydrous Sodium Sulfate 5-15
Urea 10-20
Polyethylene Glycol
(200-600 Wt. Average Mol. Wt.) 2-10
Total Water 4-8
O Die Release Agent 0-5
Inert Diluent 10-25
Optionally, small quantities of dispersant
and/or wetting agent can be included in the composi-
tion.
Particular compositions for grid applica-
tions are selected on the basis of the following
considerat:ions: (1) amount of active herbicidal
12
9~
13
chemical to be applied per unit area: (2) grid spac-
ing; and ~3) total weight of composition to be applied
per unit area. The weight of the pellets is generally
determined by the metering accuracy of the aerial
application equipment. Usually about 10-12 kg/hectare
is the minimum weight of total composition which can
accurately be applied to a given area. In some in-
stances, howe~er, total weight can be as low as 6 kg/-
hectare where well constructed, accurately calibrated
e~uipment is used. For example, to apply 1.12 kg
active chemical per hectare in a total of 11.2 kg of
composition in a generally square grid pattern of
1.8 m x 1.8 m average spacing re~uires that the com-
position contain about 10% by weight of the active
chemical and be uniformly distributed as 2990 compac-
ted pellets per hectare. Each pellet will contain
about 0.375 g of herbicidal chemical. Other composi-
tions and grid spacings are give~ in TabLe 3.
TAB~E 3
Compositions and Rates for Grid Application
Average Pellet Com- Application
Square Grid Pellets/ position Wt. ~ate,
Spacing Meters Hectare% Active Ing. Kg/hectare w/Pellet, g
Active Total Active Total
1.8 x 1.8 2g90 15 1.12 7.5 0.375 2.50
1.2 x 1.2 4480 15 2.24 14.9 0.500 3.33
1.2 x 1.2 4480 20 2.24 11.2 0.500 2.50
301.8 x 1.8 29gO 20 ~.48 22.4 1.50 7.50
1.8 x 1.8 2990 25 ~.72 26.9 2.25 9.00
This invention is further described by the
following examples. Velpar~ 90 Weed Killer is a com-
position which contains about 89-91% by weight of
3-cyclohexyl-6-dimethylamino)-1-methyl-s-triazine-2,4-
(lH, 3H)dione and about 11-9% by weight of inert
~; 13
C399~
14
diluents and process impurities.
EXAMPLE 1
The following ingredients are blended
together:
5 Ingredient Wt. (kg)
Velpar~ 90 Weed Killer 5.59
Anhydrous Sodium Sulfate 4.65
Prilled Urea 7.30
Volclay 90 Swelling 20.64
Bentonite (6.7% water)
Attaclay Inert Diluent 8.51
(3.7~ water)
Polyethylene Glycol 200 2.50
Water 0.80
After thorough blending the composition is
ground in a bantam hammer mill (Mikropul Corp.,
Summit, New Jersey) using a screen having 1 mm dia.
holes. The particle size range of the ground formula-
~ion indicated 5.9 wt. ~ larger than 150 ~, 30.2 wt. %
larger than 74 ~ and 47.6 wt ~ smaller than 44 ~.
The ground composition is dry compacted
using a model 50 KHD*briquetting press (Klockner-
Humboldt-Deutz Ag., Koln, West Germany) with rolls
having l. cc pockets to form briquettes of l. cc
volume weighing about 2.1 g each. The briquettes are
physically stable when exposed to 95~ RH atmosphere
for 100 hours and exhibit a crushing load of ll,000 g.
The peliets swell and crumble after being contacted
with l ml of liquid water.
EXAMPLE 2
This example demonstrates the effect of re-
moving the polyethylene glycol from the composition.
The composition of Example 1, without the
polyethylene glycol 200, is prepared by blending and
grinding. In this instance, however, cylindrical
shapes, 1.27 cm in diameter are formed by pressing the
composition in a cylinder and ram die using a
*denotes trade mark
14
P~ .
~9~
laboratory press and a pressure of about 450 kg/cm2
gauge.
The cylindrical shapes are exposed to 85%
and 100% RH atmospheres for 16 hours. The shapes
exposed to 85% RH swell about 10% volumetrically,
exhibit surface tackiness and are cracked. Those
exposed to 100% RH swell about 25% volumetrically,
exhibit surface tackiness and are so severely
cracked they cannot be handled without crumbling.
EXAMPLE ~
This example demonstrates the effect of re-
moving the sodium sulfat3 from the composition.
11.4 g of Velpar~ 90 weed killer, 44.4 g of
the Volclay 90, 33.3 g of Attaclay and 11.2 g of cry-
stal urea are thoroughly blended and ground as in
Example 1. The ground composition is pressed as inExample 2 to form dense, strong cylindrical shapes.
The shapes are contacted with about 0.2 ml
of liquid water which is equivalent to about 0.5 cm
of rain. The compacted shapes swell and crack ini-
tially. When allowed to dry at 23C and 40~ R~ the
cylinders rebond into strong, coherent structures.
Rewetting does not cause swelling and recracking.
9L~ 4~
16
EXAMP E 4
The following ingredients are blended together:
Ingredient WT. ! KgWT. %
Velpar~ 90 Weed Klller 5.59 11.18
5 Anhydrous Sodium Sulfate 4.65 9.30
Prilled Urea 7.30 14.60
Volclay 90 (6.7~ water) Bentonite 20.64 41.28
Attaclay (3.7~ water) Diluent7.52 15.04
Polyethylene Glycol 200 2.50 5.00
10 Stearic Acid, Die Release Agent 1.00 2.00
Water 0.80 1.60
50.00100.00
After thorough blending the mixture is ground in a
hammer-mill (No. 1 Mikro-polveri~er* Mikropul Corp.,
15 Summit, ~.J.) using a screen with lmm dia. holes.
The ground composition is dry-compacted using a
Model 220 Komarek*Roll Briquetter (K.R. Komarek Inc.,
Elk Grove Village, ILL) using rolls having 2.2cc volume
to form 2.2cc bolus shaped briquettes weighing 3.75 g
20 each and containing 10 wt % of active herbicide.
The briquettes are physically stable to 100 hrs.
exposure at 90% RH, exhibit a crushing load >11.0 kg
and exhibit an impact resistance ~10 drops. When
wetted with 1 ml of water per briquette, the briquettes
25 swell and crumble and do not rebond upon drying.
EXAMPLE 5
The briquettes of Example 4 were hand distributed
on a 1.8 meter x 1.8 meter (6 ft. x 6 ft.) square grid
pattern over four separate 0.1 hectare (0.25 acre)
30 plots at an over application rate of 11.2 kg/ha
(10 lb/acre) of briquettes and providing 1.12 kg/ha
(1 lb/a) of active herbicide. The plots contained
seedling loblolly and short-leaf pines, the desired
species being "farmed" to provide a source of pulpwood.
35 The plots also contained the undesirable hardwoods:
* denotes trade mark
16
~,~ .
- ' - . ~ .
~g~
17
dogwood; hickory; hornbean; maple; oaks; sweetgum; and
sourwood, which compete with the pines for food, water
and sunlight and seriously retard their growth.
Five months after the treatments the undesired
5 species were defoliated and dying with no apparent injury
to the pine species. One yea:r after the treatments the
hardwood species were eliminated. The pine seedings in
the treated plots exhibited larger growth and vigor
compared to similar adjacent but untreated plots.
EXAMPLE 6
The briquetkes of Example 4 were applied from a
helicopter using a Simplex~ Pneumatic Seed applicator
to distribute 22.4 ~g/ha (20 lb/A) of briquettes, in a
square grid pattern, 1.3 meter5 x 1.3 meters (4.25 feet
15 x 4.25 feet) on 1 ha (2.47A) loblolly and short-leaf
pine seedling plots. The seedling plots were 1nfested
with dogwood, blackjack oak, redoak, postoak, sourwood,
hickory, sweetgum and yellow poplar.
Five months after treatment the undesired hardwood
20 were completely eliminated with no damage to either
loblolly or short leaf pine. The pine species showed
much greater growth and vigor as compared to adjacent
untreated plots.
EXAMPI,E ?
The following ingredients are blended together and
ground in a laboratory hammer-mill:
MIX~URE A
Ingredient WT.(g) W %
Anhydrous Sodium Sulfate18.6 10.5
Carbowax~ 200 10.0 5.6
Volclay~ 200 77.0 43.4
Crystal Urea 29.2 16.4
Attaclay~ 32.8 18.5
Water 10.0 5.6
177.6 100.0
17
18
10 g portions of Mixture "A" were blended with
2.3 g of each of several wettable powder herbicides
to prepare 12.3 g of each of the following compositions:
Final Composition
Mixture "A" Acti~e In~redient. WT. ~ Active
Sample ~Compound WT. % Herbicide
1 10 Diuron 80 15
2 10 Bromacil - 80 15
3 10 Bromacil/Diuron 80 15
4 10 Tebuthiuron 80 15
Karbutilate 80 15
3.75 g portions of each of the five compositions
are dry compacted into cylindrical pellets as in Example
2. The pellets exhibit the following properties.
Impact Crushing Hunidity Stability
Strength Load24 Hrs., 88% RE, Swelling
Sample Dro~s k WT ~ain
1 8 9.0 5.0 Crumbled
20 2 >10 10.0 4.0 Cr ~ led
,5 4.o Crumbled
4 >10 11.5 4-5 Crumbled
5 >10 11.0 4.5 ~nmbled
Bri->10 11.0 3.5 Cn ~led
of
Exam
ple 1
18
:
.
19
EXAMPLE 8
The following compositions are thoroughly blended
and ground using a laboratory hammer-mill:
Sam~le 1 2 3 4
_
Ingredients, WT %
Velpar~ 90 Weed Killer11.2 11.2 11.2 11.2
Volclay~200 20.040.0 60.0 70.0
Ah~d. Sodium Sulfate 10.0 10.0 8.0 5.0
~rea 15.015.0 8.o lO.o
Carbowax~ 200 5.0 5~ 5-0 3-8
Attacla~ 32.813.8 5-8 o.o
Stearic Acid 1.0 1.0 1.0 0.0
Water 5.0 4.0 2.0 0.0
Total 100.0100.0 100.0100.0
15 The ground compositions are dry compacted as in
Example 7, and the pellets exhibit the following
properties.
I~pact Strength Crushing Load Swelling
Sample No. of (Drops) (kg) (1.0 ml water)
20 1 >10 6.0 Swells & Cracks
2 >10 11.5 Crumbles
3 5 10.5 Crumbles
4 0 8.5 Crumbles
Sample 4 contains insufficient binder to form a
25 strong impact and crush resistant pellet.
19
