Question

Deficiency of boron (B) can be corrected by application of which of the following fertilizers?
(A). Borax
(B). Boric acid
(C). Solubor
(D). Lime
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (B) and (C) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Applying lime increases soil pH, which enhances boron adsorption on soil particles and clay minerals, reducing its availability to plants. Hence, lime cannot correct a boron deficiency.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Boron deficiency in soil is corrected using boron-bearing chemical fertilizers. Alkaline substances, such as lime, are not used to supply micronutrients.

Step 2: Detailed Explanation:
- Borax (\(\text{Na}_2\text{B}_4\text{O}_7 \cdot 10\text{H}_2\text{O}\)): Contains approximately \(10.5\%\) Boron. It is a common soil-applied boron fertilizer.
- Boric Acid (\(\text{H}_3\text{BO}_3\)): Contains around \(17\%\) Boron and is highly water-soluble, making it suitable for foliar sprays or soil applications.
- Solubor (\(\text{Na}_2\text{B}_8\text{O}_{13} \cdot 4\text{H}_2\text{O}\)): Contains about \(19\%\) Boron. It is highly soluble and commonly used for foliar applications.
- Lime (\(\text{CaCO}_3\)): Is an amendment used to neutralize soil acidity. Applying lime raises soil pH, which reduces the availability of boron and can induce boron deficiency.
- Thus, (A), (B), and (C) are correct boron fertilizer sources.

Step 3: Final Answer:
The correct combination is (A), (B) and (C) only.