There are two types of components of soil:
(i) Organic Components: Organic wastes, dead animals, plants and decomposition products.
(ii) Inorganic Components: Minerals which are derived from fragmentation and weathering of rocks. The pore spaces formed between the mineral particles of soil are filled with water and gases.

The nature of any soil depends upon the rocks from which it has been formed and the type of vegetation that grows on it.

The rotting dead matter in the soil is called humus.

Clayey soil and loamy soil are rich in humus and are suitable for growing plants like wheat and gram.

Clayey soil absorbs more water but allows less water to percolate

The man digging a pit could dig with ease initially because of th~\presence of topsoil and subsoil (mainly comprising of humus and nutrients). But as he digs deeper, he finds it difficult to dig beyond a depth of 5 feet as lower layers are made up of small partially weathered rocks with cracks, crevices and with bedrock which make it hard to dig.

The upper crust of the earth, which is capable of supporting vegetation is called soil. We usually see the surface of the soil. The sides of trench sides of a hill or steep river banks are clearly visible different zones or layers. The side-view of soil zones or layer is known as soil profile.
The upper most layer of the soil is called the A-horizon or top soil. It absorbs maximum water. The top soil consists of soil particles, minerals, water and humus. The decomposed organic matter (decayed plant and animal) remains forms a spongy and brownish or blackish material known as humus. The humus makes the soil very fertile. It also increases water holding capacity of the soil. Worms, insects, algae and fungi are found in the top soil. You will also find roots of plants in this layer. Plants get essential nutrients from the top through roots.
The second layer, called B-horizon, is more compact and harder than the top soil. It consists of sand, silt and clay. This layer contains very little organic matter. It is rich in soluble minerals and iron oxides.
The third zone, called C-horizon, consists of weathered rock. It is made up of small lumps of rocks with cracks and crevices. Below the C-horizon is found the bedrock.