Figure 9.11 Some examples of beds

machine ►

Why have machines improved agricultural production?

harvester ►

combine harvesters ►

Figure 9.13 A sugar cane harvester.

9 • Land preparation

9.6 Machinery used in crop husbandry

A machine may be defined as:

• an instrument or device used for carrying out a task

• any equipment or apparatus, specially designed for a particular purpose and used for the transmission of force, power or motion to produce a desirable effect.

In agriculture, several types of machines are used for tasks such as ploughing, planting, harvesting, plucking, ear-notching and castrating. New machines are continually being designed and existing machines are re-designed and improved.

AGRICULTURAL MACHINES

1. have changed and improved agricultural production, worldwide

2. enable more farm work to be done, more effectively, per day

3. enable agricultural tasks to be done more efficiently, saving time and money 4. help to red ce the cost

of production and to increase farm profits

5. help to elle late drudgery, motivating oung people to take up agriculture as a career

Figure 9.12 The importance of machines in crop husbandry.

Seeders

seeders ► Seeders, otherwise known as planters, may be of various types. Some consist of drills, which sow seeds directly on to the soil. Sometimes drills combine seeds and fertilisers, so that the seeds are planted with an appropriate fertiliser for the crop.

transplanters ► Transplanters are machines which plant seedlings such as tomato, sweet peppers or rice, or they may plant bulbs, tubers or corms.

The advantage of a seeder is that the seeds are planted evenly and at the required density. This is a more efficient method than broadcasting the seed. The machines that can transplant seedlings speed up the operation, saving time and the cost of manual labour.

Harvesters

There are various types of harvester, each designed to harvest a specific crop. These machines speed up the process of gathering in a crop, saving time and manual labour.

The simplest types are those which can be attached to a tractor, such as the sweet potato harvester. This machine digs the tubers, lifting them from the soil on to a conveyer belt.

Combine harvesters are used for grain crops, such as rice and other cereals. This type of harvester is self-propelled and cuts, threshes and winnows the grain, which is then gathered in trailers and transported away for storage. Sugar cane can also be harvested by special combine machines.

Section B: Crop Production

Tractors

tractor ► The tractor is one of the most useful pieces of farm machinery. It is mainly used for pulling ploughs, harrows, cultivators and trailers, and for transmitting power (by means of the power-take-off shaft) to attachments (brushcutters, rotovators, fertiliser spreaders and threshers).

Which type of tractor would you recommend to a _{Tractors are built for use in different environmental situations and purposes.} farmer whose farm was 20 hectares? _{Therefore tractors will vary in:}

• size TRACTORS

• horsepower (hp) or kilowatts (KW)

What are the advantages of using a mechanical • mode of mobility: wheels or tracks Wheeled tractors I I Crawler tractors

seeder rather than sowing seeds by hand? • price, including resale value. _• two-wheeled tractors • bulldozers • four-wheeled tractors: I I • excavators

small _{I I •} graders medium-sized • loaders large • harvesters

Figure 9.14 The classification of

tractors.

Type of tractor

Two-wheeled: 5 to10 horsepower or 3.75 to 7.5 KW engines Suitable for smallholdings from I to 2.5 hectares; e.g. Merry Tiller mounted on 2 wheels; 2 handles and lever tilling light soils on flat or gently sloping land; not Gravely controls; attachments include brushcutter, difficult to operate; not suitable for use on steep

rotovator, rotary plough, trailer, slopes, rough land or dry clay soils.

Four-wheeled: Gasoline or diesel engines; 10 to 20 horsepower Suitable for small farms of less than 2.5 hectares; Small or 7.5 to 15.0 KW; small front wheels; large rear economical to use with diesel engine; limited in

wheels; pneumatic tyres; attachments include scope for tasks such as levelling and grading; not brushcutter, plough, rotovator, trailer, suitable for long hours on clay soils.

Four-wheeled: Engine capacity 30 to 60 hp or 22.4 to 44.8 KW; Suitable for medium-sized farms of 2.5 to 25 Medium similar features to a small 4-wheeled tractor. hectares; used for mowing, tilling, planting,

fertilising, spraying and threshing; economical to use with diesel engine but higher maintenance costs. Four-wheeled: Same features as other 4-wheeled tractors but Suitable for large farms of greater than 25 hectares; Large engines have a capacity of 80 to 100 hp or 59.7 to greater scope for a range of agricultural operations

74.6 KW or more; may have additional ballasting including ploughing, grading, levelling and

for increased grip in the form of metal wheel grips harvesting; higher maintenance costs; requires well- or spiked metal w

heels.

dskilf

l opera

Table 9.3 Types of tractors.

Figure 9.15 A two-wheeled tractor. Figure 9.16 A four-wheeled tractor. Figure 9.17 A crawler tractor with a

device for tilling attached.

Figure 9.19 A chisel Figure 9.20 A fertiliser

plough. spreader.

Figure 9.21 A

mouldboard plough.

Figure 9.18 A disc plough.

crawler tractors ► Crawler tractors are more powerful than wheeled tractors and have metal chain

belts on sprockets, instead of wheels and rubber tyres. They are suitable for land clearing operations, site preparation for roads and buildings and the construction of dams and embankments (levees). They are used where land is damp and slippery, covered in tree stumps and stubble and not suitable for the four-wheeled tractor. These machines are expensive, have high maintenance costs and require skilled operators. Many farmers find it more economical to hire such equipment when it the functions of a harrow.

is needed for a specific purpose, rather than investing in a machine which might

List I not be used all the year round.