Chapter 9 Mixing Materials ,Calibrating Equipment, and Calculating Aquatic Herbicide Requirements

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AFM 91-19 / TM 5-629 / NAVFAC MO-314
24 May 1989
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Chapter 9
MIXING MATERIALS, CALIBRATING EQUIPMENT, AND CALCULATING
AQUATIC HERBICIDE REQUIREMENTS
Section A -- Mixing Materials
9-2. Mixing Procedures:
a. Never pour a liquid concentrate or dry
9-1. Determining Tank Capacity:
herbicide formulation into an empty tank. Either
a. When the capacity of a spray tank is not
fill the tank with half of the water to be used,
known, or the tank is not marked to indicate the
add the herbicide, agitate, and complete the
number of gallons it contains, set the sprayer or
tank on a level place and gradually fill it with
tank is filled. Agitate or stir until all solid
known quantities of water. Mark the water
material is dissolved or suspended.
levels in gallons or fractions of a gallon on the
b. If a water-soluble powder or crystalline
side of the tank or on a calibration rod or stick
form of herbicide is to be used with a liquid
held upright in the center of the tank. The
herbicide, dissolve the solid material in the water
marks can then be used to determine the quan-
first, and then add and mix the liquid.
tity in the tank when it is partially filled.
c. If oil is to be used in an oil-water or invert
b. To quickly approximate the capacity of a
emulsion, premix the emulsifier and the oil-
spray tank in gallons, use the following calcula-
soluble herbicide with the oil in a separate
tions. All tank measurements are in inches.
container, and then add it slowly to a partly
filled tank of water with constant stirring or
(1) For rectangular tanks:
Before using, circulate the mixture
Capacity in gallons = length x width x depth
until it is uniformly white.
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d. Agitate suspensions of water-dispersible
powders and oil-water emulsions constantly or
Example:
frequently during spraying to maintain a uni-
If a tank is 60 inches long, 36 inches
form spray mixture. Use the spray mixture
wide, and 30 inches deep, the capacity is
within 1 or 2 days because some herbicides
about 60 x 36 x 30 = 280 gal
mixtures lose strength and deteriorate when
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standing.
(2) For cylindrical tanks:
e. Recommendations for herbicide application
Capacity in gallons = length x square of radius
rates are based on the active ingredient or acid
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equivalent contained, not on the total weight of
Example:
the product.
If a tank is 60 inches long and 30 inches
in diameter, the capacity is about
Section B -- Calibrating Equipment
60 x 152 = 197 gal
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9-3. The Importance of
a. The results of using herbicides depend
(3) For tanks with an elliptical cross sec-
greatly on how well, or poorly, the herbicides
tion:
are applied. This, in turn, depends on the
Capacity in gallons =
suitability of the equipment for the particular
length x (square of long diameter +
situation and the skill and care with which the
square of short diameter)
operator uses the equipment. This is especially
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true of sprayers. Accurate application at the
Example:
desired rate and uniform distribution of the
If a tank is 60 inches long, 36 inches
material are essential for good results. A sprayer
wide, 24 inches deep, and elliptical in
must uniformly distribute any quantity from 5
to 100 gallons or more per acre, because various
60 x (362 + 242) = 243 gal
weeds and situations may require a wide range
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of dilution for proper plant coverage.