Question

A soil has pH 9.8, ESP 12% and electrical conductivity 5.2 dS m$^{-1}$. What type of soil is it?

• A. Acid soil
• B. Saline soil
• C. Alkali soil
• D. Saline-alkali soil

Hint:

Soil classification:
- Saline: EC $>$ 4, pH $<$ 8.5, ESP $<$ 15.
- Alkali: pH $>$ 8.5, ESP $>$ 15, EC $<$ 4.
- Saline-alkali: EC $>$ 4, pH $>$ 8.5, ESP $>$ 15.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
This question tests knowledge of soil classification based on pH, ESP, and EC.

Step 2: Detailed Explanation:
Given:
- pH = 9.8 (alkaline).
- ESP = 12% (high sodium).
- EC = 5.2 dS m$^{-1}$ (saline).
Saline soils: EC $>$ 4 dS m$^{-1}$, pH $<$ 8.5, ESP $<$ 15%.
Alkali soils (sodic): pH $>$ 8.5, ESP $>$ 15%, EC $<$ 4 dS m$^{-1}$.
Saline-alkali soils: EC $>$ 4 dS m$^{-1}$, pH $>$ 8.5, ESP $>$ 15%.
Here, EC = 5.2 (saline), pH = 9.8 (alkaline), ESP = 12% (high sodium).
Since both salinity and alkalinity are present, it is saline-alkali soil.

Step 3: Final Answer:
Thus, the soil is saline-alkali, which corresponds to option (D).
[0.5cm]