ATF PLANi bOARD
March 1947 ET-236
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
THE APPLICATION OF SOIL FUMIGAJITS WITH A PLOW
By William C. Cook and Merton C. Lane
Division of Truck Crop and Garden Insect Investigations
The recent development of machinery for the mechanical appli-
cation of soil fumigants (2, 3) has made feasible the treatment
of much agricultural land for the control of wireworms. Many fields
however, are too small for the economical use of a large injection
machine, and often a machine is not available at the best time for
soil treatment. For these reasons it is highly desirable to
develop a simpler method of application. Carter (1) described
the application of D-D mixture (a crude product containing dichloro-
propane and dichloropropylene) by means of a pump geared to the
disk plow wheel, a thin stream of the material being dropped into
the bottom of the furrow, just ahead of the plow.
During the summer of 1946 several applicators, by which a
fumigant was dropped into the soil ahead of a plow, using only
gravity to feed the liquid, were built and used in the Walla Walla,
Wash., area. These machines, made by local farmers, were very
successful, and experimental work showed them to be at least as
efficient as the more expensive injection machines.
The construction of these plow applicators is very simple.
A tank of suitable size, usually a second-hand gasoline tank of
10 to 16 gallons' capacity, is mounted on the tractor or plow
above the point of application. A line of 1/4-inch copper tubing
leads downward from the tank to within a foot or so of the furrow
bottom, ahead of the plow. Two standard shut-off valves are
installed in the line near the tank. The upper valve serves as
a shut-off valve, while the lower, fitted with a set screw to main-
tain a constant position of the opening, is used to control the
rate of flow of the fumigant. One of these applicators installed
on a tractor is shown in figure I.
A valve system used on a two-way-plow applicator is shown
in figure 2. The middle valve is a three-way valve, by means of
which it is possible to feed the fumigant to one side or the other
or to shut off the flow. On each side of the three-way valve is
the valve that regulates the rate of flow.
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The rate of flow of the fumigant is calculated from the speed
of the tractor when the plow is drawn through similar soil, and
from the width of the furrow. A flow of 1.8 ml. per square foot
will deliver about 20 gallons per acre. Table 1 shows the flow
rates for a delivery of 20 gallons per acre for three furrow
widths at speeds between 250 and 500 feet per minute.
Table l.--Flow rates per minute to distribute 20 gallons of fumigant
per acre for three furrow widths at various tractor speeds.
Tractor speed S 12-inch : 14-inch : 16-inch
I furrow s furrow t furrow
Feet per minute Milliliters Milliliters Milliliters
250 435 507 579
300 521 608 696
350 608 710 811
400 695 811 927
450 782 913 1,043
500 869 1,014 1,159
The cost of the machines so far constructed has been about
$10 each. Since no extra cultivation is involved, there is no
extra cost of application. The performance of these plow applica-
tors has been excellent. Delivery with the tank full runs less
than 10 percent higher than when it is nearly empty. The tanks
used so far have been shallows If a deep tank, such as a 50-gallon
drum, were used, it would probably be desirable to install a
constant-level device in the feed line.
As soon as possible after plowing, the fields are harrowed
and cross-harrowed, as is the usual practice for obtaining a
good seedbed. This produces a firm, even texture of the soil,
assuring even penetration of the fumigant. Wireworm mortality
has been checked in several fields so treated, caged larvae of
the sugar beet wireworm being used. In every field in which 20
gallons (about 200 pounds) per acre of either D-D mixture or 10-
percent solution of ethylene dibramide was used, the mortality
of wireworms was well above 90 percent. The few living wireworms
were found in the top 3 inches of soil. All this work was done
on Walla Walls silt loam at soil temperatures above 50*F. at
9-inch depth, and with soil moisture within the ordinary range
for good cultivation.
The plow applicator possesses one decided advantage over the
cultivator type of injection machine. The passage of the cultiva-
tor points through the soil loosens the soil about the lines of
passage. A light drag or roller is usually drawn behind the
points to seal this opening, but this method is not too successful.
Figure 3 shows the soil to a depth of 9 inches, across the path of
an injection machine using a railroad rail as a drag. The loosened
areas along three injection lines can be detected in the picture.
The plow does not leave such loosened areas, except in some places
at the bottom of the furrow, covered by the furrow slice. The
double harrowing after plowing seals the surface more effectively
than does the drag on the injection machine*
(1) Carter, Walter.
1945. Soil treatments with special reference to fumigation
with D-D mixture. Jour. Econ. Ent. 38s35-44, illus.
(2) Hannesson, H. A., Raynor, R. N., and Crafts, A. S.
1945. Herbicidal use of carbon disulfide. Calif. Agr. Exp. Sta.
Bul. 693, 57 pp., illus.
(3) Lange, W. H.,Jr.
1945. Ethylene dibromide and dichloropropane-dichloro-
propene mixture for wireworm control. Jour. Econ.
Ent. 58: U43-645.
Figure l.--Two-way-plow applicator showing fumigant tank (A) with tubes
Leading to the furrow.
Figure 2.-Valve system used on a two-way-plow applicator for soil
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Figure 3.--Section of soil following passage of a cultivator-type
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