Question

Write the names of two chemicals for the treatment of usar soil.

Hint:

For alkaline soils (usar), gypsum is the most common amendment.

Answer 1

Step 1: Understand usar soil.
Usar soil is saline/alkaline soil, characterized by excess sodium carbonate and poor fertility.
Step 2: Treatment chemicals.
- Gypsum (CaSO$_4$): Supplies calcium ions which replace sodium ions on the soil complex, thus improving soil structure.
- Elemental Sulphur (S): On oxidation, produces sulphuric acid which neutralizes alkalinity.
Step 3: Conclusion.
Therefore, the chemicals are Gypsum and Sulphur.