Question

The concentration of salt in the irrigation water having EC of 20 dS/m is :

• A. 12.8 g/l
• B. 13.8 g/l
• C. 14.8 g/l
• D. 15.8 g/l

Hint:

To convert $\text{EC (dS/m)}$ to $\text{TDS (g/l)}$ quickly, multiply the EC by $0.64$:
$\text{TDS (g/l)} = 20 \times 0.64 = 12.8 \text{ g/l}$.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Electrical Conductivity (EC) is a proxy measurement of the concentration of Total Dissolved Solids (TDS) or salt concentration in water.
Key Formula or Approach:
For standard agricultural waters, the empirical relationship used to estimate salt concentration (TDS) from EC is: \[ \text{TDS (mg/l)} \approx 640 \times \text{EC (dS/m)} \]

Step 2: Detailed Explanation:
Given EC value: \[ \text{EC} = 20 \text{ dS/m} \] Apply the conversion factor: \[ \text{TDS} = 640 \times 20 = 12,800 \text{ mg/l} \] Convert milligrams per liter ($\text{mg/l}$) to grams per liter ($\text{g/l}$): \[ 1 \text{ g/l} = 1,000 \text{ mg/l} \] \[ \text{TDS} = \frac{12,800}{1,000} = 12.8 \text{ g/l} \] Thus, the concentration of salt in the irrigation water is $12.8 \text{ g/l}$.

Step 3: Final Answer:
The salt concentration is $12.8 \text{ g/l}$, which matches Option (A).