Define :-
A, B, C, D horizon in soil
Answers
A : Horizon or topsoil is the uppermost layer. It consists of fine particles. It contains humus so it is dark in colour. It is soft, porous and can hold water. Plants grow in this layer. Humus is the decomposed dead organic matter which makes the soil fertile.
B : Horizon or subsoil does not have much humus so it is lighter in colour. It has more minerals and pieces of rocks. It has oxides of iron and other minerals. It is a hard layer.
C : Horizon or parent rock consists of small pieces of rocks with cracks and crevices.The particles of rock found in soil come from this layer.
D : Horizon or bedrock is the lowermost layer which is very hard and non-porous. The properties of this rock help in determining the properties of the soil. This layer is very difficult to dig. Water collects over this layer to form the water table. Bedrock can also be the loose material deposited in huge quantities by rivers, glaciers and wind.
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