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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
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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
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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

Some practical advice

· Brush fires

In traditional farming; leaves and branches are burned.
The fire destroys the organic matter, so that no organic matter is left to make humus.
The brush fire destroys the organic matter and changes the soil structure.
Modern farmers do not make brush fires.

· Fallow

Cassava gives an example.

When cassava is harvested, the whole plant is lifted: the root for eating and the stems for replanting.

Almost nothing is left either on the soil or in the soil.

The cassava has taken humus from the soil, but the organic matter of the cassava is not returned to the soil. So the soil is less rich.

After growing, cassava farmers let the soil rest. They let it lie fallow.

During the fallow, the soil gets all the dead plants; it gets the organic matter from the dead plants, and the soil improves.

Soil must be given organic matter. The remains of the crop, grass, manure, provide organic matter.

· Some crops improve the soil.

When you harvest a bean plant, you take only the fruits.
The stems, roots and leaves are left to rot on the soil.
They decompose and give humus.
Beans are a crop that leaves organic matter in the soil.
The beans take humus from the soil but return organic matter to it.

· Manure

Modern farmers use animal manure.
Manure returns to the soil the organic matter taken out by the crop.

· Do not mix the soil and the subsoil.

The soil is rich in humus.
The subsoil has no humus.
In tilling, the farmer should never mix the soil and the subsoil, so as to keep his soil rich.
In planting a tree, do not mix the layers of soil.


Do not mix the layers of soil