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close this bookBetter Farming Series 04 - The Soil: How the Soil is Made up (FAO - INADES, 1976, 37 p.)
View the document(introduction...)
View the documentPreface
View the documentPlan of work
View the documentWhy we study the soil
close this folderDifferent kinds of land
View the document(introduction...)
View the documentThe soil
View the documentThe subsoil
View the documentThe parent rock
View the documentExamples of different soils
close this folderWhat is soil made of ?
View the document(introduction...)
close this folderSand
View the document(introduction...)
View the documentSandy soils
close this folderClay
View the document(introduction...)
View the documentClay soils
close this folderSilt
View the document(introduction...)
View the documentSilty soils
close this folderHumus
View the document(introduction...)
View the documentWhat humus does
View the documentSome practical advice
View the documentAir in the soil
close this folderWater in the soil
View the document(introduction...)
View the documentCirculation of water in the soil
View the documentPractical advice
close this folderLiving creatures in the soil
View the documentEarthworms
View the documentRats and other animals
View the documentTermites
View the documentOther insects
View the documentMicrobes
View the documentSuggested question paper

Examples of different soils

· Savanna soils

The depth of soil varies a great deal.
Often the soil is missing.
You can see the pebbles.


Bad savanna soil

The subsoil is very unstable.
It may become very hard.
Then a hardpan forms.
Roots cannot penetrate it.
Nothing can be grown on it.

· Mountain soils

In the mountains there is often neither soil nor subsoil.
You can see the parent rock and nothing grows.
If there is a little soil on the parent rock, a few small trees and some grass grow among the stones.

· Forest soils

The soil is rich.
The subsoil is always very poor; it contains no mineral salts; it does not become hard and does not form a hardpan.

· Soils of the same village

In various fields of the same village the layers of soil can be very different. On the slopes, for example, the soil may have been carried away by the rain.
That is why the soil is deeper in the valleys.


Soil is deeper in the valleys