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V. Developments in Spraying and Dusting Equipment
T. W. EDMINSTER AND H. F. MILLER, JR.
were manufactured during each of the intervening years. In 1947 one
buyers’ guide listed only five manufacturers of tractor-mounted powertake-off sprayers, but a hundred manufacturers were listed in 1957.
The airplane is considered an agricultural machine for applying spray
and dust materials, since an estimated 5000 planes treat over 60 million
acres annually for pest control, A U. S. Department of Agriculture
(1958~)report on the pesticide situation for 1957-1958 stated: “The
acreage treated by aircraft for pest control in California rose from 296,059
in 1946 to 5,611,000 in 1956, with the area in 1956 almost twice that in
1951.” The U. S. Department of Commerce (1957) gives a breakdown
of aviation application uses for agriculture. The U. S. Department of
Agriculture (1958d) also gives a selected list of references on aircraft
Much progress has been made in the manufacture of spray equipment for both ground machines and aircraft by the use of better materials and manufacturing techniques. Improved nozzles, pumps, valves,
as well as longer-lasting tanks and lines, have come about by the use of
higher-grade metals or newly developed synthetic materials. For instance,
as many as six different types of stainless steel are used in the manufacture of present-day spray equipment. Detailed discussion of the use and
development of spray and dusting equipment is given by Smith (1955)
and Bainer et al. (1955).
Considerable work has been done on the effect of particle and droplet
size when using different chemicals for various purposes. However, researchers are still working for a method to control droplet size and to
produce sprays with a large percentage of droplets in a narrow range
of sizes. Other problems concern methods of increasing the percentage
of material which actually sticks to the plant stem and leaf surfaces, and
ways of measuring these amounts quickly and accurately.
A new photographic and electronic counting method of measuring
spray droplet size has been reported by Farnham (1958) to be a hundred times faster than presently used methods. Brittain et al. (1955)
discuss a relatively simple method of evaluating the deposit on plants,
and Kromer (1949) relates the engineering challenge of spray application. Black (1956) reports on the corrosion and abrasion effects of pesticides on application equipment.
Sprayers for field crops are primarily of three types-tractor-mounted,
tractor-trailed, and high-clearance self-propelled. Orchard sprayers are
generally classified as high pressure or blower (mist) types. Recent developments have been the increased use of self-propelled sprayers for
RECENT DEVELOPMENTS I N AGRICULTURAL MACHINERY
ficld crops and blower (mist) typc sprayers for orchards. The introduction of blower (mist) sprayers for use on field crops, primarily vegetable
crops, has been for disease control.
Williamson ( 1958) discusses recent increased use of self-propelled
high-clearance sprayers in cotton, Black et al. (1954) describe the de-
FIG. 8. New m i s t blower sprayer maneuverable for spraying in any direction.
(Courtesy Food Machinery and Chemical COT.)
T. W. EDMINSTER AND H. F. MILLER, JR.
velopment of a high-clearance, self-propelled sprayer for sweet corn.
These sprayers have recently been equipped with attachments such a s
topping devices for cutting tops from crops, flame cultivators for use
in flaming rank-growing cotton for weed control, and granular insecticide distributors for corn borer control.
The new development of blower-type sprayers, sometimes referred
to as air-blast or mist-concentrate sprayers, is significant and their use
is rapidly expanding. These sprayers use less water, thereby applying
more concentrated spray while also obtaining equal or better coverage
than hydraulic sprayers using large volumes of water. The use of this
type sprayer for row crops and vegetables is discussed by J. D. Wilson
( 1956) (Fig. 8 ) .
Recent developments and methodology in the use of airplanes for
forest and row-crop spraying are discussed by Isler and Thornton (1955),
Young et al. (1957), Chamberlin et aZ. (1955), U. S . Department of
Agriculture ( 1954), and Anonymous ( 1956~).
Helicopters are being used to a small but increasing extent. Their
use is limited to spraying of high-value specialty crops, such as cranberries, which are difficult to get to with either ground equipment or
Although the use of dusting equipment has rapidly declined owing
to increased use of sprays in the past decade, there has been some improvement in application equipment. This is particularly true with respect to modification of dusting equipment for use of granules.
Improved hopper and metering equipment design has resulted in more
uniform distribution of dust across the swath for both ground machines
and aircraft. For aircraft, an additional small airfoil has been closely
coupled to numerous discharge points to aid in promoting rapid spreading of the materials. This new equipment dispenses liquid, dust, or
granules with only minor adjustments being necessary for dispensing
the different types of materials.
VI. Developments in Harvesting Equipment
Quality changes through improved design and manufacturing processes have produced harvesting machines which do a better job in less
time, last longer, and require less labor for operation. The number of
machines has increased, although the number of farms has decreased.
During the period 1950 through 1958, the number of grain combines
increased by 46 per cent, corn pickers by 63 per cent, pickup balers by
RECXNT DEVELOPMENTS I N AGRICULTURAL MACHINERY
201 per cent, and field forage harvesters by 215 per cent. Percentage
increase of machines on specialized crops is even greater, depending
upon the number needed and the degree of success in perfecting the
equipment. The harvesting of specialized crops is rapidly changing from
hand to mechanical methods. Scarcity of labor and tightening of the
economic situation is expediting this change-over.
Increase of mechanized harvesting contributed primarily to the 21
per cent reduction in man-hours used on farms in the past ten years.
There has been very little reduction in man-hours used for those crops
in which the harvesting has not been mechanized.
The general trend has been toward harvesting equipment that can
be operated by one man with the least expenditure of his energy. The
trend in design is toward more automatic operation, increased use of
hydraulic systems, V-belt drives, self-aligning prepacked bearings, and
lighter materials for construction where possible. Less vibration is experienced owing to better balancing of moving parts. The use of large
harvester-mounted bulk bins unloaded by gravity dumping or auger
conveyors is becoming standard practice.
There is a trend toward larger self-propelled machines for the bigger
farms. Smaller machines are being designed to mount on tractors or
other power units which can accommodate several types of equipment.
Harvesting machines are being designed to operate under a wider range
of crops and cropping conditions.
Forage crop production of over 100 million tons (excluding that used
for silage) constitutes approximately one-fifth of all harvested crop acreage in the United States. S t r i d e r and Phillips (1956) report that while
only 29 per cent of all hay was baled in 1944, 73 per cent was baled in
1954. This trend was due primarily to the introduction of automatic-tie
pickup balers, reduction of storage space requirements, and ease of handling as compared with loose hay. Chopped hay for curing and dehydration increased from approximately 2 to 7 per cent during the same
period. Long, loose hay has steadily declined during these same years
to a low of 20 per cent in 1954.
Although hay crops in general have a relatively low cash value per
acre, much progress has been made in equipment for mechanizing the
crop. Improvements in hay crushers have decreased the hazard of crop
loss under changing weather conditions. Automatic one-man-operated
balers with a second man loading the trailer has been a common practice
for the past ten years. Recently, one-man hay balers have been designed
to kick or throw the bale into the trailer, thereby eliminating one man