VII. Farm machinery

Structure of the Chapter:

Introduction:

Farm machinery allows the farmer to carry out farming operations safely, economically and within the time available. Successful management of machinery involves the selection of equipment having the correct function and capacity, and the supervision of its efficient and safe operation to achieve quality work at the lowest possible cost. After studying this chapter, students should be able to describe a number of benefits while driving a four-wheel-drive tractor, in what forms the power for the tractor is used and health and safety for the tractor driver.

 

Key Words:

Power - energy of force that can be used to do work
Pull - to move something towards yourself, sometimes with great physical effort
Shaft - a bar or rod joining parts of a machine, or transmitting power
Ram - one of various implements or devices for striking or pushing with great force
Four-wheel drive - with four wheels connected to the source of power
Ballast - a stabilizer, to stabilize
Steer - to control the direction of a vehicle
Brake - device for reducing speed or stopping motion
Performance - doing a piece of work or activity
Pivot - a central pin or point on which something turns
Track - line or series of marks left by a vehicle
Slope - the area of rising or falling ground
Ditch - a narrow channel dug in or between fields or at the sides of a road
Trailer - a transport vehicle hauled by a tractor or truck
Slurry - a mixture of water, animal excrement, urine
Cab - the separate part at the front of vehicle in which the driver sits
Incident - en event which is either unpleasant or unusual


listening

Pre-reading Tasks:

Distinguish between the terms machinery and machines.
What machines could be included into farm machinery?
Try to describe the pictures at the beginning of the pictures.

Specialist text:

The agricultural tractor

The tractor provides power for most mobile operations on the farm and needs to be flexible to carry out tasks ranging from heavy pulling to transport and loading duties. Power for the tractor is produced by its engine, and this power is used in three forms:
- as pulling power at the drawbar, to operate trailed equipment
- as rotary power at the power take-off shaft
- as hydraulic power, to operate hydraulic rams and motors

Four-wheel-drive tractors:

The majority of new tractors sold in Europe are fitted with four-wheel drive,. Driving all four wheels of a tractor offers a number of benefits:
-greater soil contact area produces a greater cohesive pull, which is particularly advantageous under wet conditions when friction is low. When conditions are good, the advantage is small.
-the pull is shared between four drive wheels, reducing each wheel’s slip and compaction. Ballast is also spread between all wheels, reducing total weight for a given tractor power.
-the powered front wheels give improved steering control in wet conditions.
-the tractor’s brakes are effective on all four wheels. Some tractors have front brakes, but normally only rear brakes are fitted, and front-wheel braking is only effective when front-wheel drive is engaged.
Some very large sized tractors have drive systems where all four wheels are the same size. This configuration produces the best performance. The relatively large turning-circle problem can partly be overcome with centre-pivot or four-wheel steering, which also allows front and rear wheels to run in the same tracks during turns. If front wheels are to contribute fully to the performance, they must be correctly ballasted.
Soil working usually is required to convert a field carrying the remains of a previous crop into an environment suitable for the establishment and the continued growth of the next crop. Burying trash, reducing compaction, producing a seedbed, shaping the soil for a particular crop and improving harvesting conditions are examples of operations involving soil disturbance. A detailed understanding of the actions and interactions of cultivation equipment, under a full range of soil conditions, is essential if the aim is to achieve the desired result at least cost.

Health and safety for the tractor driver:

Hearing loss from noise exposure and injury from tractor overturning accidents are the major risks to which a tractor driver is subjected.
Since much of the noise from a tractor is airborne, most of the sound-proofing of the cab is lost if it is necessary to leave a door or window open for access to implement controls or for ventilation in hot weather.
Tractor overturns most commonly occur sideways, when operating on steep slopes or driving too close to ditches or steep banks. Trailers, slurry tankers or other heavy, unbraked machines can push the tractor down hills. Backward overturns occur less frequently, usually from attempting to pull from a high hitch point. In an overturning incident, it is most important to hang on and stay inside the cab until the tractor has come to rest completely.

Comprehension questions:

  1. For what operations does the tractor provide power?
  2. In what forms is the power used?
  3. With what drives are most new tractors sold in Europe fitted?
  4. What does the powered front wheel give in wet conditions?
  5. What are the major risks to which a tractor driver is subjected to?
 
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Activities:

I. Decide whether the following sentences are true or false:

  1. Power for the tractor is produced by its speed.
  2. A detailed understanding of the actions of cultivation equipment is essential unless the aim is to achieve the desired result at least costs.
  3. Unequal-wheel four-wheel-drive systems are common on small and medium sized tractors.
  4. The front wheels must be correctly ballasted if they are to contribute fully to the performance.
  5. Driving all four wheels of a tractor offers only few benefits.
  6. Some tractors have rear brakes, but normally only front brakes are fitted.
  7. The pull is shared between four drive wheels, reducing each wheel’s slip compaction and linkage.
  8. Greater soil contact area produces a greater cohesive pull.
 
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II. Fill in the blanks with the correct verb form taken from the list below:

generate diameter
capacity tillage
width rim
dimensions rear
rubber row-crop

Most tractors rely on 1) tyres to transmit the power of the engine to the soil and to 2) tractive effort. The size of a tractor tyre is described by two 3) (usually in inches). The first of these gives the maximum width of the tyre section, and the second indicates the 4) of the wheel 5) on which the tyre is mounted. A 50-kW tractor can be fitted with 13.6 x 38, or 18.4 x 30 6) tyres, which are similar in overall diameter. However, the wider 18.4 x 30 tyre has a larger ground-contact area and a greater carrying 7) , and when ballasted to take advantage of this will give a 5-15% increase in tractive performance. It is not possible to use wide section tyres for 8) work, but for most 9) and haulage operations there is no restriction on tyre 10) .

 
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III. Match the following antonyms:

1) benefits   a) much
2) heavy   b) push
3) pull   c) disadvantageous
4) few   d) backward
5) outside   e) many
6) close   f) drawbacks
7) diminish   g) inside
8) less   h) increase
9) forward   i) far
10) advantageous   j) light

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IV. Complete the table with the noun or verb which has been omitted:

VERB NOUN
eliminate
drive
grow
loss
injury
risk
establish
performance
maximize
contribute
reduce

 
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V. Quiz

Look at the sentences below and choose the right answer.
1. The tractor’s engine converts chemical energy contained in diesel fuel into rotary
force
energy
power
2. The conventional engine is the best mobile power ..... at present available in terms of efficiency and weight.
capacity
source
operation
3. Current ...... cabs must reduce the noise level inside the cab.
safety
security
insurance
4. Tractor overturns most commonly occur sideways, when operating on ..... slopes.
suitable
separate
steep
5. The actions of cultivation ..... on the soil fall into a number of categories.
engines
brakes
equipment
6. Operations involving soil disturbance include burying trash, reducing compaction, producing a seedbed and shaping the soil for a particular
crop
particle
weed
7. The size of a tractor tyre is described by two
diameters
dimensions
directives
8. For most tillage operations there is no restriction on tyre
width
wide
widen
9. ..... roll a wheel along a surface, a force must be applied to overcome its rolling resistance
In order as
In order to
So that
10. The tractors ..... their tyres to transmit the power of the engine to the soil.
rely in
count to
rely on
 
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Summary:

This chapter deals with the farm machinery, particularly with the agricultural tractor, its power and health and safety for the tractor driver. Students will practise the terminology of this topic in a specialist text, in a number of activities and in a final quiz.

Literature:

The Agricultural Notebook edited by R. J. Soffe, Blackwell Publishing Company 2003

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Checks:

Comprehension Check:

  1. for most mobile operations on the farm
  2. as pulling power, as rotary power and as hydraulic power
  3. four-wheel drive
  4. improved steering control
  5. hearing loss from noise exposure and injury from tractor overturning accidents

Check I:


F, F, F, T, F, F,T, T

Check II:

  1. rubber
  2. generate
  3. dimensions
  4. diameter
  5. rim
  6. rear
  7. capacity
  8. row-crop
  9. tillage
  10. width

Check III

1f, 2j, 3b, 4e, 5g, 6i, 7h, 8a, 9d, 10c

Check IV:

Verb: lose, injure, risk, perform
Noun: elimination, drive, growth, establishment, maximum, contribution, reduction

Check V

  1. c
  2. b
  3. a
  4. c
  5. c
  6. a
  7. b
  8. a
  9. b
  10. c
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