Which of the following exchangeable sodium percentages is characteristic of alkaline soils?

Correct option is A

• Characteristics of Alkaline (Sodic) Soils:
  

  • ESP ≥15%

  • pH usually >8.5

  • Poor permeability and drainage due to sodium dispersing soil particles.

  • Hard crust formation and reduced plant growth.

  • Reduced availability of essential nutrients like calcium and magnesium.

• Reclamation of Alkaline Soils:

  • Gypsum (CaSO₄·2H₂O) is used to replace sodium ions with calcium.

  • Sulfur and organic matter help improve soil structure.

  • Leaching with good-quality water removes excess sodium.

• Difference Between Saline and Sodic Soils:

  • Saline soils have high soluble salts (EC >4 dS/m).

  • Saline-Sodic soils have both high ESP and high salts.