Question

Name and explain different Horizons of soil.

Answer 1

Soil is made up of distinct horizontal layers and these layers are called horizons.

• O Horizon - The top, organic layer of soil, made up mostly of leaf litter and
humus.
• A Horizon -The layer called topsoil; it is found below the O horizon and above
the E horizon. Seeds germinate and plant roots grow in this dark-coloured
layer. It is made up of humus mixed with mineral particles.
• E Horizon - This eluviation (leaching) layer is light in colour; this layer is
beneath the A Horizon and above the B Horizon. It is made up mostly of sand
and silt, having lost most of its minerals and clay as water drips through the
soil.
• B Horizon - Also called the subsoil - this layer is beneath the E Horizon and
above the C Horizon. It contains clay and mineral deposits (like iron, aluminum
oxides, and calcium carbonate) that it receives from layers above it when
mineralized water drips from the soil above.