PLANT PROTECTION EQUIPMENT

Introduction

The following methods have been recognized as the effective and economical ones under
different situations:

 Mechanical control
 Chemical control
 Biological control
 Agronomical methods
 Bio-physical methods
 Fire as control

In developing countries, combination of chemical and mechanical methods of weed control has
been successfully accepted.

The chemicals for protecting the plants from various injurious or organisms need to be applied
on plant surfaces in the form of sprays, dusts, mist etc.

Sprayers and dusters are available in many forms for this purpose.

Sprayers

Sprayer is a machine to apply fluids in the form of droplets.

Sprayer is used for the following purpose:

 application of fungicides to minimize fungal diseases,

 application of insecticides to control insect pests,
 application of herbicides to remove weeds
 application of micronutrients on the plants.

The main functions of sprayer are:

 to break the liquid into droplets of effective size,

 to distribute them uniformly over the plants
 to regulate the amount of liquid to avoid excessive application
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Desirable quality of sprayer

 The sprayer should produce a steady stream of spray materials in the desired fineness of
the particle so that the plants to be treated may be covered uniformly.
 It should deliver the liquid at sufficient pressure so that it reaches all the foliage and
spreads uniformly over the surface of the plant
 It should be light weight, sufficiently strong, easily workable and repairable.

Sprayer’s classification

1. Based on power source, sprayers may be classified as:

 Hand operated machines – suitable for small holdings.

 Power operated machines – suitable for treating a large area.
 Air planes – suitable for large scale work.

2. Based on spray volume, sprayers may be classified as:

 High volume sprayer - More than 400 litres of spray liquid per hectare is used.
 Low volume sprayer – Spray volume ranges between 5 to 400 litres per hectare is used.
 Ultra-Low volume sprayer – Spray volume less than 5 litres per hectare is used.

3. Based on working principle, sprayers may be classified as:

 Hydraulic energy sprayers

 Compression sprayers

Hydraulic energy sprayers

 In this category of sprayers, hydraulic pressure is thrust upon the liquid by the hand
operated pumps.
 As a result, the liquid is forced through the nozzle in the form of a spray of droplets
(diameter in the range of 300-400mµ).
 Sprayers of this type are high volume, high pressure and suitable for complete coverage
of both ground and field crops.

Bucket type sprayer

 It is very light and easily handled and develops sufficient pressure to spray small gardens
and low trees.

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 Figure: Line diagram of bucket type sprayer

Knapsack sprayer

 It is quite useful for spraying small trees, shrubs and row crops up to 2.5 m height.
 One man can spray about 0.4 – 0.5 ha in a day, thus spraying about 90 litres of spray
liquid.

Figure: Line diagram of knapsack sprayer

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Foot - operated sprayer

 It is also called pedal pump

 It is easy to operate and can be used for spraying tall crops and fruit trees up to 4 m
height.
 Sprayer can be used to spray trees up to 6 m height with additional hose.

Figure: Line diagram of foot operated sprayer

Rocking sprayer

 Such sprayers are used for spraying tall plants like coconut and sugar cane plants.
 It needs two persons to operate the sprayer, one for operating the pumping system and
another for the application of spray liquid.

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 Figure: Line diagram of rocking sprayer

Compression Sprayers

 In these types of sprayers, air is compressed into the container by the compression
air pump.
 When sufficient pressure is developed, then the delivery system is operated to obtain
spray in the form of fine droplets.
 The compressed air forces the liquid through the nozzle and the desired type of spray is
achieved.
 For this purpose, the tank is usually filled to three fourths of its capacity, leaving one-
fourth volume for the compressed air.
 The air pump is fitted vertically inside the container which acts as a force pump.

Hand compression sprayer

 The compressed air sprayer consists of an air pump, is fitted vertically inside the airtight
chamber.
 The outlet pipe is suspended in the liquid in the chamber, the end running into the
bottom of the chamber, the other end is provided with a nozzle.

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  The chamber is usually filled to three fourths of its capacity, leaving one-fourth volume
for the compressed air.
 Before spraying, the pressure is developed by pumping air into the chamber and
continued till sufficient pressure is built.
 When sufficient pressure is developed, then the delivery system is operated to obtain
spray in the form of fine droplets.
 The tank capacity is usually 14 litres.
 Frequent pumping must be done to maintain the required pressure.

Hand Atomizer

This is the smallest type of hand sprayer used to treat the plants in home garden or nursery and to
apply fly spray in the house.

Power sprayers

 Power sprayers are operated usually with IC engines.

 The prime mower capacity varies from 1 to 5 hp.
 These machines are usually portable type.
 Sometimes, power sprayers are operated by the PTO shaft of the tractor.
 Power sprayers can cover much larger area, and do the job efficiently.
 A power sprayer essentially consists of (see figure below):
(i) prime mower,
(ii) tank
(iii) agitator
(iv) air chamber
(v) pressure gauge
(vi) pressure regulator
(vii) strainer
(viii) boom
(ix) nozzles

 Prime mower - Prime mower is needed to supply power to the power sprayer. It is
usually internal combustion engine. The power generally varies from 1 to 5 HP.
 Tank - Steel tank is widely used to prevent corrosion. Plastic tanks are also getting
popular due to freedom from corrosion and ease of moulding into smooth shape. A

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 covered opening, fitted with a removable strainer is provided for easy filling, inspection
and cleaning. A drain plug is provided at the bottom of tank for draining the liquid.
 Agitator - Agitators are needed to agitate the liquid in the tank. Propeller or paddle type
mechanical agitators are provided to agitate the liquid. Horizontal shaft with flat blades
rotating at about 100 to 200 rpm may be used. Paddle tip speed in excess of 2.5 m/s may
cause foaming.
 Air chamber - An air chamber is provided on the discharge line of the pump to level out
the pulsations of the pump thereby providing a constant nozzle pressure.
 Pressure gauge - It is provided on the discharge line to guide the operator regarding spray
pressure. It should be under specified limit.
 Strainer - It is provided in the suction line between the tank and the pump to remove dust,
dirt and other foreign materials.
 Boom - It is driven by a tractor, has a long boom in a horizontal plane on which nozzles
are fixed at specified spacing. The boom can be adjusted vertically to suit the height of
plants in different fields.
 Nozzle - It is used to break the liquid into the desired spray and deliver it to plants.

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 Figure: Line diagram of power sprayer

Care and maintenance of sprayer

(i) All washers and packings should be soaked in oil or water before use.

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 (ii) The ends of the nozzle should be unscrewed and cleaned before starting the work.
(iii) When spraying is over, the sprayer should be operated for sometime with clean water
to remove sediments from the pressure vessel and the discharge tube.

DUSTERS

Duster is a machine to apply chemical in dust form.

Dusters make use of air streams to carry pesticides in finely divided dry form on the plants.

A duster essentially consists of:

 hopper,
 agitator,
 feed control
 fan or blower
 Delivery nozzle

Figure: Line diagram of rotary duster

Power duster

 The blower is directly mounted on the crankshaft of the high speed (4000 rpm) air cooled
engine.
 The air pressure is utilized to agitate the dust in the container in order to blow it through
the flexible hose pipe.
 The direction of the dust is regulated by a movable delivery spout suitably fitted with the
unit.

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  The dust can be blown up to about 6 meters height. Such a duster can cover about a
hectare in a day.
 This type of duster can be converted into a sprayer with little modifications.
 Portable type power dusters are also in use.
 They are mounted on two wheel trolleys.

Care and maintenance of dusters

 Thoroughly cleaned before and after use with a suitable brush.

 The hopper should be filled with dust about half of its capacity.
 The lid of the hopper should be closed during the operation.
 In rotary dusters, the handle should be cranked at 30 to 35 rpm for efficient performance.
 Before and after use of the duster, the dust from the fan box, suction pipe and hopper
should be thoroughly blown out.
 Pieces of paper, gunny bag and other and other foreign materials should be prevented
from getting into the hopper.
 The agitator parts and dust feed should be occasionally checked for blockage by foreign
matter.

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 HARVESTING EQUIPMENT

Harvesting plants

The operation of cutting a plant is achieved by four different actions.

 slicing action with a sharp smooth edge,

 tearing action with a rough, serrated edge,
 high velocity single element impact with sharp or dull edge, and
 A two element scissor type action.

Sickle

 It is used for harvesting crops and cutting other vegetation

 It is essentially consists of a metallic blade and a wooden handle.
 Blade is the main metallic part of the sickle.
 The tooth of serrated sickle is made sharp for efficient working in the field.
 However, harvesting by sickle is very slow and labour consuming device

Figure: Sickle

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Mower

Mower is a machine to cut herbage crops and leave them in swath. The conventional mower has
the following main parts (see figure below):

Figure: Components of a reciprocating mower

Combine harvester

 Combine harvester is a machine designed for harvesting, threshing, cleaning and

collecting the grain while it moves over the land.
 All the five operations are carried out in single operation of the harvester.
 The machine is versatile and with minor adjustments can handle a variety of crops.
 The size of the combine is indicated by the width of cut, it covers in the field.

Functions of combine harvester

 Feeding the standing crops to the cutter bar with the help of the reel
 Cutting the crop (harvesting)
 Feeding the crop to the threshing unit
 Separating the husks from grains
 Cleaning the grains
 Conveying and storing the grains

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Inside a Combine Harvester

 There is an awful lot going on inside a combine harvester—gears, blades, augers (screws
that move cut crops), conveyors, belts, levers, and wheels
 Roughly speaking, here's how a combine harvester works:

1. Cereal crops are gathered in by the header at the front, which has a pair of sharp pincers
called crop dividers at either end. Generally speaking, the wider the header, the faster and

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 more efficiently a harvester can cut a field. Different headers are used for cutting
different crops; the header is often hydraulically powered and can be raised, lowered, and
angled in different ways from the cab. The header can be removed and towed behind the
harvester lengthwise so it can fit down narrow lanes.
2. A slowly rotating wheel called the reel (or pickup reel) pushes the crops down toward the
cutter. The reel has horizontal bars called bats and vertical teeth or tines to grip the plant
stalks.
3. The cutter bar runs the entire length of the header underneath the reel. Its teeth
(sometimes called mowing fingers) open and close repeatedly to cut off the crops at their
base, a bit like a giant electric hedge cutter sweeping along at ground level.
4. Behind the cutter bar, the cut crops are fed toward the center by spinning augurs (screws)
and travel up a conveyor to the processing mechanism inside the main part of the
combine.
5. A threshing drum beats the cut crops to break and shake the grains away from their
stalks.
6. The grains fall through sieves into a collecting tank below.
7. The chaff (unwanted material) passes along conveyors called straw walkers toward the
back of the machine. More grain falls through into the tank.
8. When the grain tank is full, a tractor with a trailer on the back pulls alongside the
combine. The grain is carried up from the tank by an elevator and shoots out of a side
pipe (sometimes called the unloader) into the trailer.
9. The unwanted straw chaff tumbles from the back of the machine. Some combines have a
rotating spreader mechanism that throws the straw over a wide area. Sometimes the
straw is baled up by a baling machine and used for animal bedding

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