Question

Given below are two statements:
Statement (I):High Cu in soil causes Fe chlorosis in citrus
Statement (II):Application of potassium increases Mn & Fe content in rice
In light of the above statements,choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are true.
• B. Both Statement (I) and Statement (II) are false.
• C. Statement (I) is true but Statement (II) is false.
• D. Statement (I) is false but Statement (II) is true.

Hint:

To prevent iron toxicity (bronzing) in flooded rice, farmers are advised to apply adequate potassium fertilizers.
This practice utilizes the antagonistic relationship between potassium and iron to reduce iron uptake.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Nutrient interactions in soils can be antagonistic or synergistic.
High concentrations of one nutrient can inhibit the uptake or physiological activity of another nutrient, leading to induced deficiency symptoms.

Step 2: Detailed Explanation:
- Statement (I): High copper (Cu) levels in the soil interfere with the uptake and translocation of iron (Fe) in plants.
In citrus orchards, frequent applications of copper-based fungicides can lead to copper accumulation in the topsoil.
This high copper level induces iron chlorosis in citrus trees by competing for absorption sites on root membranes. Thus, Statement (I) is true.
- Statement (II): Potassium (K) acts as an antagonist to divalent cations like iron (\( \text{Fe}^{2+} \)) and manganese (\( \text{Mn}^{2+} \)).
In flooded rice soils, reducing conditions can cause toxic accumulations of soluble iron and manganese.
Applying potassium fertilizers helps suppress the uptake of excess Fe and Mn, protecting the rice crop from iron toxicity (bronzing).
Therefore, potassium application *decreases* (rather than increases) the Fe and Mn content in rice. Thus, Statement (II) is false.
Consequently, Statement (I) is true, and Statement (II) is false.

Step 3: Final Answer:
Statement (I) is true, but Statement (II) is false.