Question

Calculate the quantity of fertilizer required for making a 100 ppm solution of 20-10-20 in a 500 litre tank ?

• A. 150 g
• B. 250 g
• C. 350 g
• D. 500 g

Hint:

Steps for ppm calculation: 1. ppm means "parts per million" or mg/L. So, 100 ppm N = 100 mg N per liter. 2. Calculate total N needed: 100 mg/L * 500 L = 50,000 mg N = 50 g N. 3. Fertilizer is 20% N. This means 0.20 g N per 1 g fertilizer. 4. Amount of fertilizer = (Total N needed) / (N_concentration_in_fertilizer) = 50 g / 0.20 = 250 g.

Answer 1

The Correct Option is B

Step 1: Use the fertigation formula: \( \text{Fertilizer (g)} = \dfrac{\text{ppm} \times \text{Litres}}{\text{\% N} \times 10} \)
Step 2: Substitute \( \text{ppm} = 100 \), \( \text{Litres} = 500 \), \( \text{\% N} = 20 \).
Step 3: \( \text{Fertilizer} = \dfrac{100 \times 500}{20 \times 10} = \dfrac{50000}{200} \)
Step 4: \[ \boxed{250 \text{ g}} \]