Question

The characteristic of Saline-Alkali soil are

• A. pH $>$ 8.5, EC$<$ 4 dSm$^{-1}$, ESP $>$ 15
• B. pH $>$ 8.5, ESP $<$ 15, EC $>$ 4 dSm$^{-1}$
• C. pH $<$ 8.5, ESP $>$ 15, EC $<$ 4 dSm$^{-1}$
• D. pH $>$ 8.5, ESP $>$ 15, EC $<$ 4 dSm$^{-1}$

Hint:

Remember: High pH, high ESP, and low EC are indicators of sodic (alkali) soils.

Answer 1

The Correct Option is D

Saline-Alkali soils are characterized by high pH ($>$ 8.5), high exchangeable sodium percentage (ESP $>$ 15), and low electrical conductivity (EC $<$ 4 dSm$^{-1}$), indicating low soluble salt content but high sodium hazard.

Answer 2

Threshold elimination: Indian soil classification uses three cut-offs: EC = 4 dS m\(^{-1}\), ESP = 15, and pH = 8.5.
A Saline-Alkali (sodic) soil is dominated by exchangeable sodium rather than soluble salts, so its exchangeable sodium percentage exceeds 15 and its pH rises above 8.5 due to sodium carbonate and bicarbonate hydrolysis, while its electrical conductivity stays below 4 dS m\(^{-1}\) because soluble salt content is low.
Matching pH \( > \) 8.5, ESP \( > \) 15, and EC \( < \) 4 dSm\(^{-1}\) against the options identifies the fourth option as correct.