Note: Descriptions are shown in the official language in which they were submitted.
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Method for Preparation of Glyphosate Composition
Field
[001] This invention relates to a method of preparing aqueous glyphosate
compositions in a spray tank from relatively water insoluble glyphosate acid
powder
and to a method of controlling weeds by application of the aqueous glyphosate
composition.
Background
[002] Glyphosate in the form of its salts, as opposed to glyphosate in its
acid form
(N-phosphonomethylglycine), is the most common form of glyphosate that is used
as
an active agent in agriculture and industrial herbicidal liquid formulations
(soluble
liquids) or solid formulations (soluble powders or water dispersible
granules).
Glyphosate salts have been preferred because of glyphosate acid's relative
lack of
solubility in water. Thus, glyphosate salts have been chosen as the form to
use in the
vast majority of herbicidal applications because they can be readily dissolved
in water
by farmers in a spray tank shortly before spray application to plants to be
controlled.
[003] The glyphosate salt compositions are generally sold in liquid
formulations
composed of glyphosate in a salt form and suitable adjuvants, such as
surfactant,
which may enhance the absorption of the active agent in the plants to be
controlled.
The content of the active salt is generally expressed in terms of the
glyphosate acid
equivalent, that is, the equivalent acid content. This allows the activity of
different salt
compositions to be compared based on the glyphosate component. Typical
loadings
of commercial salt solution concentrates contain from 20 to 600 g/L glyphosate
acid
equivalent. The salt forms commonly contain glyphosate with amines or other
cations. The amines and cations include isopropylamine, monoethanolamine and
potassium in in the case of liquid formulations (soluble liquids). Glyphosate
is also
sold in the form of water dispersible granule (WDG) formulations which contain
the
water-soluble glyphosate salt and adjuvants such as solid carriers and wetters
which
allow the granule and water-soluble salts to be rapidly dissolved in a spray
tank by the
farmer. The farmer will generally mix the aqueous concentrate or WDG with
water in
a tank shortly before spray application to the weeds or the area of land on
which
weeds are to be controlled.
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[004] The formulation of glyphosate salt aqueous concentrates and WDGs is
carried out by manufacturers in industrial plant facilities and requires
sophisticated
handling of strong bases such as amines and metal hydroxides many of which are
have the potential to cause serious injury from skin or eye contact,
inhalation or
ignition. Formulation of spray tank compositions from glyphosate acid powder
(in the
absence of a proton acceptor) has not generally been contemplated.
Inappropriate
handling of the glyphosate acid and other chemicals not only risks injury but
can lead
to inaccurate dosing of the active if the glyphosate acid is not fully
dissolved.
Ineffective formulating can lead to precipitation or settling of glyphosate
leading to
underdosing or blockage of spray equipment.
[005] Glyphosate acid has poor water solubility which produces fine
precipitates in
water, particularly at low temperature or in hard water which can lead to
blocking of
spray nozzles with the risk of ineffective weed control from under dosing of
weeds.
While in pure water glyphosate has a solubility of about 12 g/L at 202C the
solubility is
significantly reduced at lower temperature and/or in even moderately hard
water
commonly available in farming districts.
[006] Although glyphosate is normally formulated in the form of a water-
soluble salt,
the herbicide is converted to the acid form in the plant to provide herbicidal
activity.
Amine salts, on the other hand, are generally water-soluble but often have an
unpleasant odour. Furthermore, some amines used in forming salts have a low
flash
point and present significant process hazards for storage of these amines and
preparation of the salts.
[007] AU 2010330690 teaches the inclusion of glyphosate acid with an
agriculturally acceptable glyphosate salt in a solid glyphosate formulation
such as a
granule. The glyphosate acid and the glyphosate salt are in admixture and the
mole
ratio of glyphosate acid to total glyphosate moieties is at least 10% and less
than
50%.
[008] AU 2007260586 teaches a method of preparing a spray tank mix of
glyphosate which involves forming a dilute mixture of a first pack containing
a mixture
of an alkaline composition together with a surfactant, particularly
ethanolamine which
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is added first to the spray tank and a second pack of glyphosate acid,
subsequently
added to the spray tank to form a glyphosate salt in situ. The handling of
alkaline
materials is required. Also, the need to use a pack containing a mixture of
the alkaline
material and surfactant means farmers cannot benefit from reductions in the
price of
formulation ingredients and they cannot choose alternative ingredients to suit
the
conditions due to the need to use a package comprising the strongly alkaline
material.
[009] There is a need for a method of preparing an aqueous glyphosate acid
tank
mix from glyphosate acid in powder form, which is typically the form in which
glyphosate is manufactured, and which allows glyphosate acid to be delivered
in the
acid form without prior formulation of the glyphosate acid with surfactant
adjuvants or
alkaline materials. It is also desirable for end users such as farmers to have
the
flexibility to use different adjuvants in an on-farm method and use
combinations of the
glyphosate acid with different herbicides if desired. It is also desirable to
provide tank
mixes of (i) glyphosate acid from glyphosate acid in powder form and (ii)
other
pesticides such as one or more herbicides, insecticides and fungicides so that
the
tank mix provides a broader spectrum of pest control.
[0010] The discussion of documents, acts, materials, devices, articles and the
like is
included in this specification solely for the purpose of providing a context
for the
present invention. It is not suggested or represented that any or all of these
matters
formed part of the prior art base or were common general knowledge in the
field
relevant to the present invention as it existed before the priority date of
each claim of this
application.
Summary of Invention
[0011] We have now found that glyphosate acid spray solution may be prepared
in
the spray tank by combining glyphosate acid powder and ammonium sulfate in the
spray-water.
[0012] There is provided a method of preparing a glyphosate solution in a
spray
tank, comprising:
adding ammonium sulfate to spray-water in the spray tank;
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adding glyphosate acid powder to spray-water in the spray tank containing the
ammonium sulfate;
adding a wetter surfactant to spray-water in the spray tank.
[0013] The glyphosate powder is added to the spray tank following addition of
at
least a portion of the ammonium sulfate. Addition of the glyphosate powder
following
the ammonium sulfate addition provides significant advantages in enhancing the
dissolution of glyphosate acid and reducing the occurrence of solid
precipitates and
crystallisation.
[0014] In one embodiment the method comprises a first step of partially
filling the
spray tank with spray-water, and a subsequent step of filling the partially
filled spray
tank with spray-water to make up the required spray-water volume following the
addition of ammonium sulfate, glyphosate acid, wetter, and any further
herbicide or
adjuvant.
[0015] In one set of embodiments the method comprises:
adding an initial amount of water to the spray tank;
adding ammonium sulfate to the spray tank, optionally in an aqueous mixture;
adding an aqueous slurry of glyphosate powder to the spray tank following
addition of at least a portion of the ammonium sulfate, preferably all the
ammonium
sulfate;
adding a wetter to the spray tank;
optionally adding further water to make up the desired spray volume following
addition of the ammonium sulfate glyphosate acid slurry and wetter; and
optionally adding a further pesticide during the method.
[0016] In one set of embodiments the wetter surfactant is added to the spray-
water
following addition of at least a portion of the glyphosate acid and preferably
following
addition of the glyphosate acid.
Detailed Description
[0017] The invention involves a method of formulating an aqueous composition
of
glyphosate acid in a spray tank using ammonium sulfate. The ammonium sulfate
is
typically added to water in the spray tank and may be added in finely divided
form
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such as a powder, granules or as an aqueous mixture. The ammonium sulfate may
be pre-dissolved in the water or may be in the form of a slurry in which the
ammonium
sulfate may be partly dissolved. It is typically convenient to use ammonium
sulfate in
the form of a powder or granules which are forms readily available for
suppliers for a
range of agrochemical uses. The ammonium sulfate may be formed into a solution
or
slurry prior to addition to the spray-water or if desired may be added to the
spray-
water in the form of powder or granules to form the solution of ammonium
sulfate. The
ammonium sulfate in one embodiment is in crystalline form for example as a
powder
or granules containing crystalline ammonium sulfate.
[0018] There invention provides an efficient method for the on-farm
formulation of
aqueous glyphosate acid solution in spray-water. The method involves the
addition to
spray-water of powdered glyphosate acid technical material and low-cost, safe
and
commonly available agricultural adjuvants can be individually purchased by the
farmer. In the method of the invention, these adjuvants include agricultural
ammonium
sulfate and agricultural non-ionic wetters. The addition of the ammonium
sulfate to the
spray-water prior to powdered glyphosate acid provides an unexpected level of
stability under conditions of hard water and low temperatures which allowing
farmers
the flexibility to formulate aqueous glyphosate acid composition directly from
powdered glyphosate available from manufacturers without the additional costs
associated with pre-formulated proprietary glyphosate compositions.
[0019] We have also observed that the aqueous solution compositions prepared
according to the invention show enhanced efficacy (per unit weight (wt) of
glyphosate
acid equivalent) against important weeds such as ryegrass, capeweed, melons
and
provide enhanced early brown-out.
[0020] The composition of the ammonium sulfate may comprise at least 70wt /o
ammonium sulfate, preferably at least 80 wt% ammonium sulfate, more preferably
at
least 90wt /o ammonium sulfate, such as at least 95 wt% ammonium sulfate.
Where
present other materials may, for example be inert fillers, granulation agents
or other
materials used in granulation or preserving reducing caking of ammonium
sulfate.
[0021] The ammonium sulfate acts as a week acid. It was surprising to find
that the
use of ammonium sulfate in place of an alkaline material would provide a spray
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solution containing a solutions of the ammonium sulfate and glyphosate having
an
acid pH of, for example 2 to 3.5 such as 2.5 to 3. The low pH of 2 to 3.5 such
as 2.5
to 3 of the final glyphosate solution allows alkaline materials to be
completely omitted
and the glyphosate to remain in free acid form from addition to the spray
water to the
final glyphosate acid solution.
[0022] The glyphosate acid is generally in powder form and typically is of
particle
size of maximum dimensions of no more than 1 mm preferably no more than 0.5 mm
such as 0.01 to 0.5 mm.
[0023] The glyphosate powder will typically contain glyphosate acid and
optionally an
inert carrier although powders of technical grade glyphosate acid are
preferred due to
their economical pricing.
[0024] The reference to glyphosate acid herein is the glyphosate free acid and
will
be understood to be clearly distinguished from glyphosate salts used in
solutions or
granules of prior art solid and liquid compositions of glyphosate.
[0025] The glyphosate acid powder is typically free of alkali and is
relatively insoluble
in typical spray-water. The glyphosate acid powder will typically contain at
least 90 clo
by weight glyphosate acid on the dry weight of the powder such as at least 95%
by
weight. Technical grade glyphosate acid available from manufacturers is
typically
about 95 wt% to 97 wt% purity.
[0026] In a preferred embodiment the glyphosate acid powder is added to the
spray
tank as a slurry of the powder. The slurry of powder may be prepared by
turbulent
mixing in an induction hopper which may also be referred to in the art as an
induction
vessel for transfer of chemicals to the sprayer.
[0027] An induction hopper may be used which provides mixing of the glyphosate
acid powder with water in a swirling flow such as a vortex action. It is
particularly
preferred that at least the glyphosate acid powder is added via formation of a
slurry of
the powder in an induction hopper. In a further embodiment the ammonium
sulfate
and glyphosate acid powder are each added via the chemical induction hopper
either
simultaneously or preferable the ammonium sulfate is added at least in part
prior to
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addition of the glyphosate acid powder. Induction hoppers known in the art are
a
smaller tank than the spray tank providing a swirling flow such as a vortex of
water
within the induction hopper for mixing water with the concentrated material.
In the
present invention particularly the glyphosate acid and optionally one or both
ammonium sulfate and wetter are added to the spray tank after mixing with
water in
an induction hopper. The induction hopper is adapted to deliver the aqueous
mixtures formed in the hopper into the spray tank. It may be placed above the
spray
tank or may be adapted to transfer the contents of the hopper to the spray
tank via a
transfer conduit. Suitable induction hoppers for providing swirl (e.g. vortex)
mixing
are available from Hardi Industries under the trade mark "Granni Pot" or from
Gold
Acres of St Arnaud, Victoria, Australia.
[0028] In one embodiment the preparation and spraying of the glyphosate
composition in accordance with the invention is conducted using spray
apparatus
comprising a chemical induction hopper adapted to deliver chemicals mixed with
water to a spray tank and one or more boom spray arms comprising spray
nozzles,
the spray tank being adapted to deliver an aqueous composition in the spray
tank to
the spray nozzles.
[0029] In one embodiment the aqueous composition in the spray tank is
continuously
agitated in the time period during addition of the ammonium sulfate,
glyphosate acid
powder, wetter and any other materials and preferably through addition of the
water
used to make up the final volume of the spray mixture.
[0030] The final spray mixture volume in the spray tank may in one set of
embodiments be from 1000 L to 15,000L, preferably about 5,000L.
[0031] In one embodiment the invention further comprises spray application of
the
glyphosate composition from the spray tank to an area of land in which growth
of
undesirable plants is to be controlled.
[0032] The rate at which the spray-water is applied to an area of land in
which weeds
are to be controlled will depend on the concentration of the glyphosate, the
presence
of any other herbicides and the chosen wetter surfactant. In some embodiments
the
spray-water may be applied to an area at a rate of at least 20 L/ha,
preferably at least
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30 L/ha, more preferably at least 40 L/ha such as at least 50 L/ha, at least
60 L/ha or
at least 70 L/ha. The spray-water may be applied to an area at a rate of no
more than
400L/ha, preferably no more than 300 L/ha such as no more than 200 L/ha or no
more than 100 L/ha.
[0033] The rate of application of spray-water onto an area of land on which
plants
are to be controlled by the herbicidal composition is preferably 30 L/ha to
200 L/ha,
more preferably 40 L/ha to 100 L/ha, preferably about 60 L/ha to 80 L/ha.
[0034] In one embodiment, the quantity of ammonium sulfate added to the spray
tank is 0.3 kg/100L to 5 kg/100L, preferably 0.5 kg/100L to 5 kg/100L of spray-
water,
preferably 1 kg/100L to 3 kg/100L of spray-water, more preferably about
2kg/100L of
spray-water. Preferably an amount of ammonium sulfate in this range is added
to the
spray water prior to addition of the glyphosate acid powder.
[0035] The quantity of glyphosate acid powder added to the spray-water is
preferably
from 1 g/L to 20 g/L spray-water, preferably about 5g/L spray-water (based on
final
spray-water volume).
[0036] The concentration of ammonium sulfate in the final spray-water
composition
is typically at least 0.3 wt% such as at least 0.5 wt%, at least 1 wt%, at
least 1.5 wt%
or at least 2 wt%. Typically, the amount of ammonium sulfate in the final
spray-water
composition is no more than 6 wt%, preferably no more than 5 wt%, such as no
more
than 4 wt%, no more than 3 wt% or no more than 2 wt% The concentration of
glyphosate in the final spray-water volume is preferably 0.3 wt% to 3 wt% of
the
spray-water composition. Thus, typically addition to the spray water of
ammonium
sulfate prior to addition of glyphosate acid is at least 0.3 wt% such as at
least 0.5
wt%, at least 1 wt%, at least 1.5 wt% or at least 2 wt%. Typically, the amount
of
ammonium sulfate added to the spray water spray-water prior to glyphosate acid
is no
more than 6 wt%, preferably no more than 5 wt%, such as no more than 4 wt%, no
more than 3 wt% or no more than 2 wt% wherein the amounts are based on the
final
solution composition.
[0037] The concentration of glyphosate in the final spray-water volume is
preferably
0.3 wt% to 3.
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[0038] The quantity of glyphosate acid powder added to the spray tank is
typically
sufficient to provide an application rate of 0.1 kg/ha-2 kg/ha, preferably
about
0.5kg/ha. The glyphosate may be introduced to the spray tank in the form of an
aqueous slurry which can be prepared in an induction hopper such as those
described herein. The induction hopper will typically provide mixing of the
glyphosate
acid powder and water in a swirling action.
[0039] The concentration of glyphosate and the application rate in g/ha will
depend
on whether the composition is used in crop-topping weed control or general
control of
weeds such as fallow or pre-seed treatment. In the case of general weed
control the
concentration and rate may be determined having regard to the type and age of
weed
and the rate required for effective control. In the case crop-topping the
concentration
of glyphosate is typically in the range of 1.8 g/L to 3.0 g/L such as about
2.4 g/L. In
the case of weed control the concentration is typically 4.0 g/L to 10 g/L and
preferably
g/L to 8 g/L. In terms of grams/hectare the crop-topping rate is typically 80
g/ha to
180 g/ha. For general weed control in fallow or pre-seed weed control the rate
is
typically 300 g/ha to 1000 g/ha.
[0040] The glyphosate may be transferred to the spray tank from a bag
containing,
for example 10 kg or 15 kg of glyphosate, by pouring the glyphosate from the
bag into
an induction hopper, which may be fitted onto the spray tank opening, so as to
form a
slurry of the glyphosate powder prior to addition to the spray tank. The
amount of
glyphosate may be measured using a chute attachment fitted to a bulker bag to
measure weighed amounts of glyphosate which may be delivered into a container,
such as a suitable bag for containing for example 10 kg or 15 kg of
glyphosate.
[0041] It is particularly preferred that the wetter is in the form of a liquid
composition
at 20 C. The liquid composition may, and preferably will, comprise a high
concentration of the wetter surfactant such as at least 600g/L preferably 800
g/L of
wetter surfactant, more preferably at least 900 g/L wetter surfactant and
still more
preferably at least 1000 g/L of wetter surfactant.
[0042] The wetter surfactant is itself preferably in the form of a liquid at
20 C or a low
melting point solid. Low melting point solids may, and preferably will, be
presented as
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liquid formulations. It is particularly preferred that the wetter surfactant
is a liquid at
C. This allows convenient handling of the wetter surfactant by farmers who are
more accustomed to dealing with liquid compositions of wetters and the high
concentration of liquid wetter surfactant allows storage and handling of this
component to be conveniently managed.
[0043] The wetter surfactant is present preferably present in the final spray-
water
composition in an amount of at least 0.05 wt% preferably at least 0.1 wt%. The
wetter
surfactant is typically present in the final spray-water composition in an
amount of no
more than 2 wt%, preferably no more than 1.5 wt%, more preferably no more than
1
wt% and still more preferably no more than 0.5 wt% of the final spray-water.
[0044] The wetter components may comprise a surfactant chosen from the group
consisting of alkylaryl ethoxylates, alkyl ethoxylates,
amidoaliphaticbetaines,
alkylamine alkoxylates particularly fatty amine ethoxylates such as
tallowamine
ethoxylates, cocobetaine, alkoxylated aliphaticamines, alkylpolyglucosides,
alkylglycosides, aliphatic amines, quaternary amines, aliphatic acetates,
ethylene
diamine ethoxylates, amphoteric surfactants such as polyoxyethylene aliphatic
amine
oxides and polyoxyethylene aliphatic ether salts, amine oxides and
amphoacetates.
The term aliphatic is used to include saturated as well as unsaturated
hydrocarbon
chains and includes linear and branched chains. Glyphosate-synergising
surfactants
typically contain at least one aliphatic group containing 8 to 22, more
frequently 12 to
18 carbon atoms. Discussions of glyphosate-synergising surfactants are
provided in
US 6207617, WO 95/16351, US Pub 20030158042, US Pub 20050170965 and US
Pub 20040224846 the contents of which are herein incorporated by reference.
The
preferred surfactants are selected from aliphatic, betaines
amidoaliphaticbetaines and
tallow amine ethoxylates.
[0045] Preferred surfactant include alcohol ethoxylates, alkylarylethoxylates,
fatty
amine ethoxylates, organosilicones and mixtures of alcohol ethoxylates and
alkylarylethoxylates. Suitable agriculturally acceptable surfactants are
available from
these classes. In one embodiment the wetter added to the spray tank comprises
a
nonionic wetter, more preferably comprises at least one wetter chosen from
alkylphenol ethoxylates, such as octyl phenyl ethoxylates and nonyl phenol
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ethoxylates, and alcohol ethoxylates, more preferably the wetter surfactant
comprises
both a nonylphenol ethoxylate and an alcohol ethoxylate. One specific example
of a
suitable wetter is "Wetter 1000" available from FMC Australia which contains
1000 g/L
nonyl phenol and alcohol ethoxylates.
[0046] The method may be conducted at ambient temperature where the
temperature. Preferably the method is conducted using water at a temperature
of at
least 5 C preferably at least 10 C, more preferably at least 15 C and most
preferably
at least 20C. Unlike processes used in commercial manufacture of glyphosate
for
farm use the components generally are not heated. Accordingly, the temperature
of
the water is generally not more than 40 C and may be not more than 35 C such
as
not more than 30 C or not more than 25 C. Water may be heated by running it
through black polymer (e.g. polyethylene) pipe or other means such as solar
heating
or direct conductive heating.
[0047] The glyphosate solution prepared according to the method may be used in
method of the invention may be used in spay application to plants to control
plant
growth such as in the preparation of fallow land, pre-sowing preparation of
land and
crop-topping. "Crop-topping' is the application of a non-selective herbicide
(in this
case glyphosate) prior to crop harvest when the target weed is at
flowering/early grain
fill. The selectivity of the crop-topping process is dependent on a sufficient
gap in
physiological maturity between crop and weed. Crop-topping is particularly
useful in
control of weeds in pulse crops,
[0048] Accordingly, in embodiment there is provided a method as described
herein
further comprising spray application of the glyphosate solution onto an area
of land in
which the growth of undesirable plants is to be controlled.
[0049] In one set of embodiments the spray application is used in preparation
of
fallow land or pre-so land preparation. In a further set of embodiments, the
spray
application of the glyphosate solution is carried out over a plant crop to
provide crop-
topping.
[0050] The method for preparation of the glyphosate acid solution may include
addition of a co-pesticides, such as herbicide, fungicides and insecticides,
such as
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one or more herbicides or insecticides registered for pest control in
croplands and
pastures. The co-pesticide may be added at any stage during the method such as
after the mixing of the ammonium sulfate and glyphosate acid. The co-pesticide
may,
for example, be added in the form of a water-soluble salt, a solution of a
water-soluble
salt or emulsifiable concentrate of an ester. The co-pesticide component when
used is
added to the spray tank at some time before completing the addition of spray-
water.
The co-pesticide may be an acid, acid-salt or ester functional pesticide such
as
chosen from the aromatic acid herbicides and their salts and esters.
[0051] The relevant herbicides may include:
benzoic acid herbicides such as cambendichlor, chloramben, dicamba,
2,3,6-TBA and tricamba;
pyrimidinyloxybenzoic acid herbicides such as bispyribac and pyriminobac;
pyrimidinylthiobenzoic acid herbicides such as pyrithiobac;
picolinic acid herbicides such as aminopyralid, clopyralid, florpyrauxifen
halauxifen and picloram;
quinolinecarboxylic acid herbicides such as quinclorac;
phenoxyacetic herbicides such as clacyfos, 4-CPA, 2,4-D, 3,4-DA, MCPA and
2,4,5-T;
phenoxybutyric herbicides such as 4-CPB2, 4-DB, 3,4-DB, MCPB and 2,4,5-TB;
phenoxypropionic herbicides such as cloprop, 4-CPP, dichlorprop,
dichlorprop-P, 3,4-DP, fenoprop, mecoprop and mecoprop-P; and
quinmerac.
[0052] The additional herbicide may be in the form of an ester or salt.
[0053] The additional pesticide when present may be selected from the group
consisting of dicamba, aminopyralid, clopyralid, picloram, quinclorac, 2,4-D
ester,
MCPA, dichlorprop, dichlorprop-P, mecoprop and mecoprop-P herbicides.
Preferred
herbicides and insecticides for inclusion as co-pesticides may be selected
from the
group consisting of cypermethrin pendimethalin, oxyfluorfen, trifluralin,
diuron,
metolachlor, chlorpyrifos, simazine and atrazine.
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[0054] In some embodiments of the invention the aqueous glyphosate acid
composition during preparation in accordance with the invention is tank mixed
with c
co-pesticide liquid composition. Examples of co-pesticides which may be tank
mixed
in liquid form include trifluralin, s-metolachlor, prosulfocarb, 2,4-D
isobutylester,
carfentrazone and oxyfluorfen. Some specific examples of these compositions
are
commercially available as Trifluralin 480, s-metolachlor 960, prosulfocarb
800, 2,4-D
IBE 800 (isobutyl ester), carfentrazone 240 and oxyfluorfen 240. The number
following the pesticide name generally refers to the concentration of the
active in
grams per litre of liquid composition. The co-pesticide is preferably in the
form of a
suspension concentrate, solution concentrate or emulsifiable concentrate.
[0055] The 2,4-D ester co-herbicide may be added in a formulation in an amount
of
at least 40% on a weight/volume (w/v) of the 2,4-D ester herbicide (based on
acid
equivalent), preferably more than 60% w/v, more preferably about 62.5% w/v.
[0056] The term "spray-water" refers to the water used in formulating aqueous
pesticidal compositions for spray application in control of pests especially
pesticidal
formulations, which are in a diute form to provide a sprayable preparation,
for
example, a pressure pack ("aerosol") or commercial scale mobile boom sprayer,
for
domestic, horticultural or agricultural use. The concentration of materials in
the spray
water refers to the final spray water volume which may, in accordance with the
described process be made up to the final volume following addition of the
materials
such as ammonium sulfate, glyphosate acid, wetter and optionally additional
pesticide.
[0057] The terms "acid equivalent", "a.e." and "gly acid equiv." are used to
compare
the active glyphosate forms such as between different salts or between salts
with
glyphosate acid with reference to the equivalent amount of glyphosate acid.
[0058] The term "ha" is used as an abbreviation of hectare and g/ha and kg/ha
refer
to grams per hectare and kilograms per hectare respectively.
[0059] Where the terms "comprise", "comprises", "comprised" or "comprising"
are
used in this specification (including the claims) they are to be interpreted
as specifying
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the presence of the stated features, integers, steps or components, but not
precluding
the presence of one or more other features, integers, steps or components, or
group
thereof.
[0060] The invention will now be described with reference to examples which
are
provided for the purpose of further understanding embodiments of the invention
but are
not intended to limit the scope or applicability of the invention to the
specific examples.
EXAMPLES
[0061] Example 1
[0062] Spray-water was run into a 5000L spray tank on a boom spray rig. The
water
was passed through a chemical induction hopper mounted on the spray rig, and
the
passage of water in the chemical induction hopper caused the water in the
hopper to
swirl.
[0063] As the spray tank was filling up, ammonium sulfate was added to the
swirling
water stream in the chemical hopper (at a rate of 2kg per 100L of final spray-
water
volume).
[0064] After addition of the ammonium sulfate, glyphosate acid technical
material
(95% to 97% purity) was added to the swirling water stream in the chemical
hopper
(at a rate of 0.5kg per 100L of final spray-water volume).
[0065] After addition of the glyphosate acid technical material, Wetter 1000
(comprising 100g/L of nonylphenol ethoxylates and alcohol ethoxylates) was
added to
the swirling water stream in the chemical hopper (at a rate of 250 ml wetter
concentrate per 100 L spray-water.
[0066] Example 2 (tendency of glyphosate acid to precipitate))
[0067] This example shows that the propensity of glyphosate acid to
crystallise at
low temperature in water of low hardness (tap water) is decreased if
increasing levels
of ammonium sulfate (AMS) are added to the water before the addition of
glyphosate
acid.
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[0068] Materials
= Glyphosate acid technical powder 97% active (Gly-97)
= Ammonium sulfate small granules (AMS)
= Wetter 1000 (WA)
= Tap water of low hardness
[0069] Protocol
= Solutions of AMS were made by adding 1% and 2% AMS to low-hardness tap
water.
= 0.5% glyphosate acid (Gly-97) was added to the AMS solution at 20 deg C.
= 0.25% Wetter 1000 was added to all liquors
= Solubility (of Gly-97) at 20 deg C was assessed in both liquors.
= Propensity of Gly-97 to crystallise after 3 hrs at 6 deg C was assessed
in both
liquors.
[0070] Results
= Both liquors were clear and free from crystals at 20 deg C.
= The liquor made with 1% AMS and 0.5% gly-97 was assessed as being at high
risk of precipitation at low temperature.
= The liquor made with 2% AMS and 0.5% gly-97 was assessed as being at low
risk of precipitation at low temperature.
[0071] Example 3 (solubilisation of glyphosate acid in aqueous solution of
ammonium sulfate)
[0072] This example shows that the capacity of an aqueous solution to
solubilise
glyphosate acid increases significantly as increasing amounts of AMS are
introduced
into the aqueous solution.
[0073] Materials
= Glyphosate acid technical powder 97% active (Gly-97)
= Ammonium sulfate small granules (AMS)
= Tap water of low hardness
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[0074] Protocol
= Solutions of 0%, 1%, 2% and 7% AMS were prepared in low-hardness tap
water.
= Varying quantities of Gly-97 were added to the above solutions with
stirring at
18 deg C.
= The capacity of the solutions to solubilise various quantities of Gly-97
was
assessed, based on the quantity dissolved within 15 mins of addition to a
stirred liquor.
[0075] Results
= At 0% added AMS, 8g/L of Gly-97 was soluble in low-hardness tap water,
however at 8.5 g/L Gly-97 and above some Gly-97 remained undissolved.
= At 1% added AMS, 8.9g/L Gly-97 was soluble in low-hardness tap water.
= At 2% added AMS, 11.1 g/L Gly -97 was soluble in low-hardness tap water.
= At 7% added AMS, 15.9 g/L Gly-97 was soluble in low-hardness tap water.
[0076] Example 4. Bioefficacy of glyphosate acid in AMS solution)
[0077] The following treatments shown in Table 1 were applied to control
ryegrass
weeds (late tillering stage) and Capeweed (6-leaf rosette stage).
[0078] Table 1
Treatment Treatment Treatment rate
(per
number hectare)
Ti Untreated control (UTC)
12 First add 1% AMS to spray-water in spray tank, 464 g Gly-
97
then add finely divided Gly-97
T3 First add 1% AMS to spray-water in spray tank, 464 g Gly-
97, 120 ml Wetter
then add finely divided Gly-97, then add 1000
Wetter 1000
T4 First add 1% AMS to spray-water in spray tank, 1 L
then add Glyphosate 450 specialty liquid
Glyphosate formulation
T5 First add 1% AMS to spray-water in spray tank, 957 ml
then add Glyphosate 470 (specialty liquid
Glyphosate formulation
Note: T3 is a composition in accordance with the invention.
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[0079] Application protocol (post-emergent).
[0080] The application equipment was a handheld 2m boom, the nozzle size was
110-015, the nozzle type was "Agrotop" Flat fan air induction, spray water
application
rate 60 Ilha, spraying pressure 230 kPa.
[0081] Assessment Timings (day after application =DA)
= 7 DA
= 12 DA
= 21 DA
[0082] Assessment Protocol (weed brownout)
[0083] Brownout score was based on visual assessment of weed phytotoxicity (0-
100% scale, where 0 = no damage and 100 = total weed death.) Results of the
assessment are shown in Table 2 below.
[0084] Table 2
% rating Effects
0 Non-evident
Negligible: slight discoloration, distorting and/or stunting barely seen
Slight: discoloration, distortion and/or stunting clearly seen
Moderate damage: moderate discoloration, marked distortion and/or
stunting, recovery expected
Substantial damage, much discoloration, distortion and/or stunting. Some
damage irreversible.
Majority of plants damaged, many irreversibly, some necrosis, discoloration
and severe distortions
Nearly all plants damaged, most irreversibly, some plants killed (<40%),
substantial necrosis and distortion
Severe; substantial number of plants killed (40-60%), much necrosis and
distortion
Very severe: majority of plants killed (60-80%), remainder show much necrosis
and wilting
Remaining live plants (<20%) mostly discoloured and distorted permanently or
desiccated
100 Complete loss of plants.
[0085] Statistical Analysis
[0086] Data was recorded in "Agriculture Research Manager" software program
and
statistically analysed using an analysis of variance with mean values
summarised and
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separated using Least Significant Test at 5% level of probability. Statistical
analysis is
shown in Table 3 below.
[0087] Table 3
Treatment no Brownout, 7 DA Brownout, 12 DA Brownout,
22 DA
Ti 0.00 c 0.00 d 0.00 c
12 23.33 b 78.67 d 90.00 b
13 26.67 ab 91.00 a 99.67 a
14 21.67 b 86.67 b 98.67 a
15 28.33 ab 86.00 b 100.00 a
Note: In Table 3 values reported with different letter are statistically
significantly different.
[0088] Discussion
[0089] At 12 days after application, weed brownout using T3 (the method of the
invention) was significantly greater than for other treatments. The
achievement of
more rapid brown-out is a significant benefit in terms of improved farmer
satisfaction
with the new method of use of glyphosate.
[0090] Example 5 (Gly-97 solubility in hard water)
[0091] 2% AMS was added to hard water (CaCO3 270 mg/ml, TDS 598 ppm) and
the maximum amount of Gly-97 that could be dissolved was measured at a range
of
temperatures and the results are reported in Table 4 below.
[0092] Table 4
Temperature deg C Max conc sol Gly-97 Gly acid equiv g/L
Solution pH
in g/L
7.96 7.72 3.0
10.58 10.26 2.9
12.50 12.13 2.8
13.08 12.69 2.7
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25 15.12 14.67 2.6
30 17.58 17.05 2.5
35 19.66 19.07 2.5
[0093] Example 6 (Gly conc preferred range)
[0094] It was established that if 2% AMS is dissolved in spray-water, a
concentration
of Gly-97 of up to 1.2% (preferably up to 1%) was viable to enable spray
application
under a range of spraying conditions and spray-water compositions.
[0095] Example 7 (examples of spray tank water preparation according to the
invention)
1. Half fill total required volume of water into spray tank and maintain full
agitation
throughout filling
2. Add 2% AMS (based on the full required volume)
3. Add spray pH adjuster if required (e.g. citric acid)
4. Add Gly-97 slowly though an induction hopper as tank is filled to about 75%
total
required spray-water volume. Minimise dust from powder handling by opening bag
corner to pour out powder close to liquid surface in hopper and if necessary,
engage overhead spray in induction hopper.
5. Add other tank mix products and then fill spray tank to total required
water volume.
6. Add surfactant at 0.2% of tank mix volume (e.g. 4Farmers Wetter 1000 -
1000g/L
non-ionic alcohol ethoxylate).
[0096] Example 8. Spray-water preparations according to the invention.
[0097] Table 5
Spray- Spray- Spray-water mixing sequence Agricultural use
water water (after AMS 2% has been
code rate prepared) - does not include
(L/ha) water addition steps
SWC1 50 (i) 120 g/ha Gly-97, (ii) 0.2% Spray top barley
grass after head
Wetter 1000 emergence
SWC2 75 (i) 564 g/ha Gly-97, (11)80 ml Pre-seeding
control of emerged and
alpha cypermethrin 250 SC, (iii) pre-emerged weeds.
Emerged
0.25% Wetter 1000 (250 weeds targeted include
Barley grass,
m1/100L), (iv) 300 m I/ha 24D Annual Ryegrass, Brome
grass,
Capeweed, Long fruited turnip,
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ester 680 EC, (v) 1.6 L/ha Indian hedge mustard,
Soursob,
Pendimethalin 330 EC, Sand fescue, volunteer
cereals,
medics and wild oats
SWC2a 75 As for SWC2 but 24D ester
replaced with 100 ml/ha
Oxyfluorfen
SWC3 75 i) 564 g/ha Gly-97, (11)80 ml alpha As for SWC2
cypermethrin 250 SC, (iii) 0.25%
Wetter 1000 (250 m1/100L), (iv)
300 ml/ha 24D ester 680 EC, (v)
1.1 L/ha Trifluralin 480 EC
SWC4 75 As for SWC3 but 24D ester replaced As for SWC2
with 100 ml/ha oxyfluorfen
SWC5 80 (i) 500 g/ha Gly-97, (ii)500 gm/ha Pre-seeding
control of emerged weeds
diuron 900 DF, (111)0.2% wetter and pre-emergent weed
control.
(200m1/100L), (iv)1.0 L/ha Emerged weeds targeted
were Annual
metalochlor 720 EC, (v)100 ml/ha ryegrass, Wild oats,
Bromegrass, Sand
oxyfluorfen 240 EC Fescue, Capeweed, Wild
geranium
(Storks bill -Erodium sp, Salvation Jane,
Wild raddish, Sub Clover.
SWC6 70 (i) 500 g/L Gly-97, (ii) 750 glha As for SWC5
Simazine 900 WG, (iii) 250 g/ha
Atrazine 900 WG, (iv)0,2% Wetter
1000 (v) 100 ml/ha Oxyfluorfen 240
EC, (v) 140 ml/ha Chlorpyrifos 500
EC
SWC 7 80 (i) 500 g/ha Gly-97, (ii) 0.2% Wetter Pre-seeding
control of emerged weeds
1000, (iii) 2.0 L/ha Trifluralin 480 EC, and pre-emergent weed control.
(iv)100 ml/ha Oxyfluorfen 240 EC, Emerged weeds targeted
were Annual
(v)140 ml/ha Chlorpyrifos 500 EC ryegrass, Wild oats,
Bromegrass, Sand
Fescue, Capeweed, Wild geranium
(Storks bill -Erodium sp.
SWC 8 80 (i) 600 g/ha Gly Gly-97, (ii) 0.2% As for SWC 7
Wetter 1000, (111)100 ml/ha
Oxyfluorfen
SWC 80 (i) 650, 700, 750 and 800 g/L Gly-97, As for SWC 7
8a,b,c,d otherwise as for SWC 8
SWC 9 90 (i) 650g/ha Gly-97, (ii) 0.2% Wetter As for SWC 7
1000, (iii) 100nril/ha Oxyfluorfen 240
EC, (iv)1.5 L/ha Prosulfocarb 800 EC,
(v) 1.5 L/ha Trifluralin 480 EC
SWC 10 90 (i) 700 g/ha Gly-97, (ii) 0.2% Wetter As for SWC 7
1000, (iii) 100m1/ha Oxyfluorfen,
(iv)2.0 L/ha Trifluralin 480 EC
SWC 90 (i) 800 g/ha otherwise as for SWC As for SWC 7
10a 10
SWC 11 90 (i) 1000g/ha Gly-97, (ii) 5g/ha Pre-seeding
control of emerged weeds
Metsulfuron methyl 600 WG, (iii) and pre-emergent weed
control.
0.2% Wetter 1000 (200m1/100L), Emerged weeds targeted
were: Annual
ryegrass, Wild oats, Bromegrass, Sand
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(iv)100 ml/ha Oxyfluorfen 240 EC, Fescue, Capeweed, Wild
geranium
(v)2.0 L/ha Trifluralin 480 EC (Storks bill -Erodium
spõ Sorrel, Wild
Radish, Couch Grass.
SWC 12 90 (i) 800 g/ha Gly-97, (ii)500 g/ha Pre-seeding
control of emerged weeds
Diuron 900 WG, (iii)200 g/ha and pre-emergent weed
control.
Metribuzin 750W6, (iv)0.2% Emerged weeds targeted
were Annual
Wetter 1000 (200m1/100L), (v)100 ryegrass, Wild oats,
Bromegrass, Sand
ml/ha Oxyfluorfen 240 EC, (vi) 1.5 Fescue, Capeweed, Wild
geranium
L/ha Triflural in 480 EC (Storks bill -Erodium
sp.
[0098] Example 9
[0099] Agronomic Observations Associated with the use of Spray-water
Preparations of Example 8
[00100] Table 6
Spray-water Observation
code
SWC1 Worked well and reduced viable seed set. Could be seen
in the following
season by a notable reduction in barley grass plants germinating.
SWC2, No compatibility issues, good weed control
SWC3
SWC4 Very good weed control. Higher rate of glyphosate used
as weeds were
older and more established, no compatibility issues
SWC 5 Good weed control. No issues with compatibility
SWC6 Good weed control. Applied after 8pm in darkness with
high humidity no
compatibility issues
SWC7 Good weed control, no compatibility issues
SWC 8 and Good weed control. Higher glyphosate rates used on
larger older plants
8 a,b,c later in the season, when temperatures were lower.
SWC 9 Good weed control, no compatibility issues
SWC 10, Good weed control, no compatibility issues
10a
SWC 11 Good weed control, no compatibility issues
SWC 12 Good weed control, no compatibility issues
[00101] Note Selection of Wetters
[00102] Commonly available agricultural examples include:
= Alcohol ethoxylates
= Allkylaryl ethoxylates (including nonylphenol and octylphenol
ethoxylates)
= Alcohol ethoxylates plus alkylphenols
= Fatty amine ethoxylates
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= Organosilicones.
[00103] Preferred for this invention are alcohol ethoxylates, alkylaryl
ethoxylates and
blends thereof. For example, wetters of this type are available under the
trade name
"Wetter 1000" sold by 4 Farmers, a liquid product which comprises 1000g/L
nonylphenol and alcohol ethoxylate blend.
[00104] Process for adding glyphosate acid technical material to a Spray Tank.
[00105] The options include:
[00106] Option A
= Place a bulker bag containing glyphosate acid technical material in the
field.
= Install a chute arrangement (such as a `Fledbag`) to the bulker bag
outlet,
which enables controlled removal of powder contents, e.g. controlled removal
into a bag placed on a set of scales (which enables controlled removal of a
given weight).
= Unload the contents of the weighed bag into an induction hopper that
feeds
into the spray tank.
[00107] Option B
= Provide glyphosate acid material in 10 or 15 kg bags and unload the bags
into the induction hopper that feeds into the induction hopper.
[00108] Option C
= Provide Glyphosate acid material in 10 or 15 kg water-soluble bags and
place the bag into the spray tank (which has been at least partially filled
with spray-water.
[00109] Example 10 - BIOEFFICACY DATA (MELONS)
[00110] The following foliar post-emergent treatments shown in Table 7 were
applied
to Afghan melons (Citrullus lanatus) weeds. The weed growth stages were Melon
Cotyledons ¨ 1 true leaf, Melon vine 2 leaf-reproductive.
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[00111] Table 7
Treatment Treatment Treatment rate
(per
number hectare)
Ti Untreated control (UTC)
T2 First add 1% AMS to spray water in spray tank, 368 g
Gly-95 technical
then add finely divided Gly-95 (95% glyphosate glyphosate = 350g
technical powder), then add Wetter 1000 glyphosate acid
T3 First add 1% AMS to spray water in spray tank, 737 g
Gly-95 technical
then add finely divided Gly-95, then add 250 ml glyphosate = 700g
Wetter 1000 per 100L of spray water glyphosate acid
T4 First add 1% AMS to spray water in spray tank, 400 g
Glyphosate 875
then add Glyphosate 875, then add 250 ml (ammonium
glyphosate) =
Wetter 1000 per 100L of spray water. 350 g glyphosate
acid
equivalent
T5 First add 1% AMS to spray water in spray tank, 800g
Glyphosate 875
then add Glyphosate 875, then add 250 ml (ammonium
glyphosate) =
Wetter 1000 per 100L of spray water. 700 g glyphosate
acid
equivalent
[00112] Application protocol (post-emergent)
[00113] The application equipment was a handheld 2m boom, the
nozzle size
was 110-015, the nozzle type was "Agrotop" Flat fan air induction, spray water
application rate 100 L/ha, spraying pressure 250 kPa.
[00114] Assessment Timings (day after application =DA)
= 6 DA A (day after application)
= 10 DA A
= 19 DA A
[00115] Assessment Protocol (weed brownout)
[00116] Brownout score was based on visual assessment of weed
phytotoxicity
(0-100% scale, where 0 = no damage and 100 = total weed death.) Details are in
Table 8 below.
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[00117] Table 8
% rating Effects
0 Non-evident
Negligible: slight discoloration, distorting and/or stunting barely seen
Slight: discoloration, distortion and/or stunting clearly seen
Moderate damage: moderate discoloration, marked distortion and/or
stunting, recovery expected
Substantial damage, much discoloration, distortion and/or stunting. Some
damage irreversible.
Majority of plants damaged, many irreversibly, some necrosis, discoloration
and severe distortions
Nearly all plants damaged, most irreversibly, some plants killed (<40%),
substantial necrosis and distortion
Severe; substantial number of plants killed (40-60%), much necrosis and
distortion
Very severe: majority of plants killed (60-80%), remainder show much necrosis
and wilting
Remaining live plants (<20%) mostly discoloured and distorted permanently or
desiccated
100 Complete loss of plants.
[00118] Statistical Analysis
[00119] Data was recorded in "Agriculture Research Manager"
software program
and statistically analysed using an analysis of variance with mean values
summarised
and separated using Least Significant Test at 5% level of probability.
The results are shown in Table 9.
[00120] Table 9
Treatment no. Brownout, melons Brownout, melons,
10 DA A 19 DA A
Ti 0 d 0 d
12 57b 62b
13 73a 83a
14 42c 53c
15 63 ac 82a
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[00121] Note: In the above table values reported with a
different letter are
statistically significantly different.
[00122] Discussion
[00123] From the above table it can be seen that treatment T2
according to the
invention (at 350g/ha glyphosate acid) provided significantly better weed
brown-out
than treatment T4 (same glyphosate acid equivalent as T2, same ammonium
sulfate,
same wetter conc.) ¨ the only difference between the two treatments is that
glyphosate acid was used in T2 rather than ammonium glyphosate in T4.
[00124] Without wishing to be bound by theory, it is believed
that the superior
efficacy in T2 arose because glyphosate acid in the spray tank was in acid
(rather
than neutralised) form.
[00125] Tank-Mix Co-Pesticides
[00126] Compositions in accordance with the invention may be
prepared
according to T3 of Table 1 with variation to include a further tank-mixed
pesticide in
the form of a liquid compositions shown in Table 10. The copesticide was added
following the AMS and glyphosate acid. The specified co-pesticides in liquid
form
were found to be compatible when tank-mixed in carrying out the method of the
invention. The water used was tap water in Welshpool Western Australia.
[00127] Table 10
Compatibility testing
Test Tank-mixed co-pesticide Second tank mixed co-pesticide
1 Trifluralin 480 _
2 s-metolachlor 960 ¨
3 Trifluralin 480 Prosulfocarb 800
4 Prosulfocarb 800 _
5 2,4-D IBE 800 _
6 Ca rfentrazone 240 ¨
7 Oxyfluorfen 240
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