Tài liệu tiếng anh - LAMNGHIEPVN.INFO (Hưng Bùi) UNIT 8

Tài liệu tiếng anh - LAMNGHIEPVN.INFO (Hưng Bùi) UNIT 8 tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập...

UNIT 8: THE COMBINE HARVESTER (A)

1 The combine harvester is used to harvest all types of grain and seed crops and its

use has relieved farmers of much of the burden of harvest It has not taken all the problems out of harvesting, most of which are created by weather conditions, but it has enabled farmers to rescue crops which otherwise may have been lost Fewer acres of crops are now left to perish in the fields

2 The combine was first developed for use in countries where the climate is more

suitable for grain production and it was said that the climate in such countries as the British Isles is totally unsuitable for its use This is not true Combine will work in quite damp conditions, but where the conditions are not ideal, they must be used in conjunction with a grain drier where the grain can be dried to a safe moisture content for storage

3 Its use results in a big reduction of time and layout required to harvest a given

crop because one man, or at the most two men only, are needed to operate the machine Other labour is required to transport the grain to the farmstead, but this is not excessive There is no stooking, carting, stacking, or any of the other work associated with harvesting when the binder is used The combine cuts and threshes the grain in one operation

Combine types

4 Three main types of combines are available and these are :

(a) tractor p.t.o driven combine,

(b) tractor-drawn, engine-driven combine,

(c) self-propelled combine

5 The tendency today is towards the use of the self-propelled type because of

certain advantages that it has over the other two It is more or less a self-contained unit propelled and having the threshing mechanisms powered by its own engine This means that it is not necessary to provide a tractor to drive it and/or pull it It is usually quite easy

to manoeuvre and work in the field because all the controls used to operate it are close to the driver; and when he becomes acquainted with them, he finds it no more difficult to drive than his tractor Probably the worst hazard confronting the driver of a self-propelled combine is the constant cloud of dust surrounding him whilst he is working with the machine This is much worse when crop conditions are very dry However, it is possible

to have fitted to a combine, an air-conditioned cab which considerably alleviated the dust problem

6 Self-propelled combines are made in widths of cut ranging from about 4 - 16m

(5 - 20 ft), the latter being used on the great grain-growing areas in such countries as Canada In this country such wide cutter-bars can present problems when it is necessary

to move the combine from field to field down narrow country lanes, and 965 cm (12 ft) of cut is a common size

7 Of the other two types of combines the main difference is the way in which they

are driven but in both cases a tractor is required to haul the combine In one, the tractor hauls the machine which is driven by an engine, whilst in the other tractor hauls and drives the combine by the p.t.o shaft The width of cut of these types generally does not exceed 560 cm (7 ft) but this does not mean that their output is necessarily lower than a larger-cut self-propelled combine Combine output depends more on the capacity of the

threshing and cleaning mechanism within the machine than on width of cut it will take.

Combine layout

8 The combine harvester can be described as a mobile threshing machine because

it differs little from the stationary thresher except that a crop is fed into a combine much more evenly and continuously as it move forward Figure 1 shows the various working parts of a typical self-propelled combine and the flow of the crop through it Reference should be made to this in conjunction with the following text in unit 4

Fig 1 A section through a combine harvester.

The cutter-bar

9 The cutting mechanism on a combine harvester is the same as that on a binder,

consisting of a finger bar and reciprocating knife This method of cutting crops has been used for many years now and, provided that the mechanisms are properly maintained, it is satisfactory The mower is another machine which employs this method The knives used

on combines and binders operate at a slower speed than the mower knife because the dry straw crop is easier to cut than a swath of grass Furthermore, it is normal practice to use

a serrated edged knife on machine cutting straw crops whilst the mower uses a smooth edged knife Very often it is found necessary to use a smooth edged knife on a combine

if there is a lot of green undergrowth to be cut, but it is better to avoid cutting this undergrowth if at all possible

10 Figure 2 shows methods used to provide knife movement The drive to the

crank pulley is usually by a V-belt and this should be kept correctly tensioned to prevent any loss of knife speed

11 The height of the cutter-bar is adjustable vertically by mechanical or hydraulic

control and it is usually arranged so that the whole cutter-bar bed and reel rises and lowers as a complete unit

Fig 2 Methods of providing knife movement

Text and illustration from SHIPPEN et al., Basic Farm Machinery,Pergamon Press

I COMPREHENSION CHECK:

1 Has the combine solved all the problems of harvesting ?

2 Can a combine work in damp climate ?

3 How must they be used in damp climate ?

4 What work does a binder eliminate ?

5 What danger does the driver of a self-propelled combine face ?

6 What is the main difference between type (a) and (b) ?

7 What does combine output depend on ?

8 What does Figure 6 show in addition to the parts ?

9 What do a mower and a combine have in common ?

10 How do you adjust a cutter-bar ?

II VOCABULARY:

1 Look at the first paragraph again What words have the same meaning as:

- save - made

- made it possible for - something difficult or troublesome to do

2 Look at paragraph 2 again What word has the opposite meaning to :

- without; separated from

3 Look at paragraph 3 again Can you explain the words:

- stooking

- carting

- stacking

4 Look at paragraph 4 and 5 again What words have the same meaning as:

- familiar with - move about

- danger - facing

5 Look at paragraph 6 again and say what this word refers to:

- line 2: latter

6 Look at paragraph 7 again What words have the same meaning as:

- be more than one

- pull

7 Look at paragraph 8 again Can you explain what is meant by:

- the flow of the crop

8 Look at paragraph 9 again What words correspond to these definitions:

- kept in good working order

- having a toothed edge, like a saw

- ridge of wheat, grass etc., lying after it has been cut

- plants etc growing at a lower level than the crop

9 Look at paragraph 10 and 11 again What word has the opposite meaning to:

- horizontally

III GRAMMAR:

1 Active or Passive voice ?

• Change the following sentences into passive or active voice

1 Today they grow watermelons worldwide

2 The first Europeans were growing this kind of vine in the Mississippi Valley when they arrived there

3 The watermelon is usually considered to have originated in Africa

4 They harvest watermelons when they are mature but not overripe

5 A long, warm growing season is required for watermelons

6 They are harvested by hand and loaded on trucks or trailers

7 Until recently only seeded types were on the market, but seedless cultivars have now been introduced

2 Defining and non-defining relative clauses

Look at these:

The water which can be taken up by the plant roots is called the available water The amount of water which is then retained by the soil is called the field capacity

* The clauses in italics define the kind of water: they are defining relative clauses The pore space, which may be filled with air or water or both, is a network of

spaces or channels

Nitrogenous fertilizers, which have nitrogen as the main food element, strengthen

plant tissues

* Here the clauses in italics gives us additional information about the pore space and fertilizer They are non-defining relative clauses They are separated from the rest of

the sentences by commas

Use the relative clauses to combine each pair of sentences into a single sentence In

each case say whether the relative clause is defining or non-defining:

1 The amount of water depends on a number of factors The amount of water is required for irrigation

2 Soil texture is the characteristic of soil Soil texture determined by the amount of silt, sand, clay and organic matter

3 The topsoil or the surface soil is a layer about 8-45 cm deep Most of the plant roots are found in the topsoil

4 A leguminous crop will add as much nitrogen to the soil per acre as 3 to 10 tons

of farmyard manure A leguminous crop is plough under

5 Banana is a starchy staple in many tropical regions of the world Banana is usually considered a fruit in the United States

6 A compost is a mixture of partly broken down material This material is usually made up of leaves or grass cutting

7 Organic matter is broken down most rapidly in warm, moist soils The soils are well limed and well aerated

8 The amount of humus formed is greatest from plants Plants have a lot of strengthening (lignified) tissues (e.g straw)

9 Fungi attack the aerial parts of the crop, the leaves, stems etc Fungi can be controlled by means of chemical substances These chemical substances are known as fungicides

10 Fertilizer or manure is required for rice cultivation The quantity of fertilizer or manure depends on the fertility of the soil and the nutrients The nutrients are released from the rooted weeds and stubble The weeds and stubble are ploughed in during cultivation

3 Short-form relative clauses

Relative clauses often appear in a shortened form The relative pronoun and the

form of verb to be can be omitted and with, the -ing form of the verb, past participle,

adjective or noun may be used instead

E.g Rice varieties with short erect leaves respond well to high level of fertilizer Rice varieties having short erect leaves respond well to high level of

fertilizer

The quantity of fertilizer required for rice cultivation partly depends on the variety of rice used.

Common nitrogen fertilizers suitable for rice are ammonium sulphate & urea Urea, the substance in human and animal urine, is a nitrogenous fertilizer.

* Combine each of the following pairs of sentences into a single sentence Then shorten the relative clauses

1 Viruses are very small organisms They are usually transmitted by means of insects

2 Nematodes are small worms in the soil that enter plant roots They cause serious losses in some crops, particularly in the tropics

3 Compound fertilizers are multiple nutrient materials They supply two or three plant nutrients simultaneously

4 It is essential to understand the materials The materials are available to the farmer to maintain the supply of minerals in the soil

5 Fungi are microscopic organisms These organisms produce thread-like growths These growths are known as hyphae

6 The types of disease organisms are fungi and bacteria They are found in the soil They attack the roots of plants and they cause root rot and wilt

7 Another fertilizer is urea This fertilizer contains nitrogen

8 A soil will contain quite a high proportion of calcium Such a soil has a pH value

of 6.5 or more

9 A compost is a mixture of partly broken down material This material is usually made up of leaves or grass cutting

10 Fungi attack the aerial parts of the crop, the leaves, stems etc Fungi can be controlled by means of chemical substances These chemical substances are known as fungicides

New words and expressions:

- the combine harvester:

- be used in conjunction with:

- safe moisture content:

- excessive (adj.):

- tractor p.t.o driven combine:

- tractor-drawn, engine-driven

combine:

- self-propelled combine:

- manoeuvre (v.):

- become acquainted with:

- air-conditioned cab:

- alleviated:

- stationary thresher:

- the cutter bar:

- reciprocating knife:

- mower (n.):

- smooth edged knife

- serrated edged knife:

- crank pulley:

máy gặt đập liên hợp được dùng kết hợp với

độ ẩm an toàn quá lớn, quá nhiều máy gặt được lái bằng máy kéo có p.t.o máy gặt bằng động cơ, đầu máy kéo máy gặt liên hợp tự đẩy

thao tác trở nên quen thuộc với cabin có gắn máy điều hòa (nhiệt độ) được giảm bớt

máy đập/tuốt (lúa) cố định thanh cắt

dao cắt (chuyển động qua laị) máy cắt cỏ

dao phẳng dao răng cưa trục tời

IV FURTHER READING: THE REEL

The purpose of the reel is twofold Where a crop is standing well, the reel must steady it against the cutter-bar whilst it is being cut Where the crop is not standing well, and may be in a tangled and flattened mass, the reel must pull it into the cutter-bar for cutting and feeding into the combine

Generally, a fairly standard type of reel, known as the pick-up reel, is used and there are few badly laid crops that it cannot effectively pull into the combine, provided that it is correctly set This type of reel has spring tines fitted to it which can be set at an angle if necessary

The other type of reel is known as a bat reel and its use is restricted to crops in good standing condition It is not fitted with tines for pulling in laid crops

To provide for different crop conditions, certain adjustments can be made to the reel For example, the reel must not strike the crop any more than necessary otherwise grain will be shed out of the ears and on the ground This will happen if the reel speed is too fast On the other hand, if the reel speed is too slow the crop will be pushed forward

by the cutter-bar and fall beneath it The speed at which the reel rotates can therefore be altered to suit the volume of crop Alteration is usually brought about by fitting the different size of reel-drive sprocket

It is also necessary to be able to raise and lower the reel whilst the combine is working and this is done so that it can be held in its correct position according to the height of the crop It should be just low enough to have a steadying action on the crop If

it is set too low, the straw will be carried around on the reel bars and tines An hydraulic

or mechanical control may be provided to make this adjustment

One other important adjustment is necessary and this is to be able to move the reel forward and backward if necessary The usefulness of this is when a crop is laid forward away from the cutter-bar

* Put questions about:

1 The purpose of the reel 2 Different types of reel

3 Their uses 4 Adjustments for different crop conditions

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