What does the code “Bn” typically signify in the context of soil horizons?

✅Explanation:
In the context of soil horizons, the code "Bn" refers to a B horizon that is enriched with sodium ions (Na+). This horizon is typically found in sodic soils, which are characterized by poor structure, low permeability, and high pH due to sodium accumulation.

• 🔑Key Points:
The A-Horizon or Topsoil
-This layer is rich in organic material and is known as the humus layer. This layer consists of both organic matter and other decomposed materials. The topsoil is soft and porous to hold enough air and water.
-In this layer, the seed germination takes place and new roots are produced which grows into a new plant.
-This layer consists of microorganisms such as earthworms, fungi, bacteria, etc.

🛑 Additional Information:::
The O-Horizon
-The O horizon is the upper layer of the topsoil which is mainly composed of organic materials such as dried leaves, grasses, dead leaves, small rocks, twigs, surface organisms, fallen trees, and other decomposed organic matter.
-This horizon of soil is often black brown or dark brown in color and this is mainly because of the presence of organic content.
The E-Horizon
-This layer is composed of nutrients leached from the O and A horizons.
-This layer is more common in forested areas and has lower clay content.
-The B-Horizon or Subsoil
-It is the subsurface horizon, present just below the topsoil and above the bedrock.
-It is comparatively harder and more compact than topsoil. It contains less humus, soluble minerals, and organic matter.
-It is a site of deposition of certain minerals and metal salts such as iron oxide.
-This layer holds enough water than the topsoil and is lighter brown due to the presence of clay soil.
-The soil of horizon-A and horizon-B is often mixed while ploughing the fields.
The C-Horizon or Saprolite
-This layer is devoid of any organic matter and is made up of broken bedrock. This layer is also known as saprolite.
-The geological material present in this zone is cemented.
The R-Horizon
-It is a compacted and cemented layer.
-Different types of rocks such as granite, basalt, and limestone are found here.