Better Farming Series 17 - Groundnuts (FAO - INADES, 1977, 40 p.) Marking out the boundaries of the field (introduction...) How to calculate the area of a field

Better Farming Series 17 - Groundnuts (FAO - INADES, 1977, 40 p.)

Marking out the boundaries of the field

18. You must mark out the boundaries of the field before you start preparing it.

You will need to know how to measure your field. For this your field will need to be either square or rectangular. That is, its corners must be right angles.

How can you make a right angle? Put a stake at O in the diagram.

Tie a string to the stake and extend it along the line OB until the free end is 3 metres from the stake.

Do the same thing with a string from O to A, and make that distance 4 metres.

Move the ends of the strings at A and B until they are just 5 metres apart.

Now the angle at O is a right angle.

Why make a field with right- angled corners?

- It is easy to calculate the area of such a field.

- You will be a modern farmer who knows: how many groundnut plants you should have on this field; how much fertilizer you should apply; whether the field yields a good or poor harvest.

You need to know the area of the field in order to make these calculations.

You need to know the area of the field

How to calculate the area of a field

19. To calculate the area of a field with right angles at the comers, multiply the length by the width of the field.

Example: a field is 100 metres long and 100 metres wide; its area is 100 x 100 = 10000 square metres (m²).

A square metre is a square measuring 1 metre In length and 1 metre in width.

One hectare = 10 000 m².

Example: a field is 200 metres long and 50 metres wide; its surface is 200 x 50 = 10000 m².

It is also 1 hectare.

A field which is 71 metres long and 71 metres wide, has an area of 71 x 71 = 5041 m².

A field which is 100 metres long and 50 metres wide, has an area of 100 x 50 = 5 000 m².

These are both fields of half a hectare.

Before you put your stakes along the boundary of the field, you must ask permission to cultivate the field according to the local laws and customs.

You must ask permission to cultivate the field