Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Farmyard manure or composts application increases water holding capacity of the soil.
Reason (R) : Compost and FYM application increases the soil temperature by 3 - 4$^\circ$C.
In the light of the above statements, choose the most appropriate answer from the options given below :
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FYM improves:
1. Soil aggregation & pore space
2. Water retention (WHC)
3. Cation Exchange Capacity (CEC)
It moderates (buffers) soil temperature rather than causing a steady temperature rise.
Both (A) and (R) are correct and (R) is the correct explation of (A)
Both (A) and (R) are correct but (R) is NOT the correct explation of (A)
(A) is correct but (R) is not correct
(A) is not correct but (R) is correct
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The Correct Option isC
Solution and Explanation
Step 1: Understanding the Question:
The question evaluates the physical effects of organic amendments (FYM and compost) on soil properties like water holding capacity and soil temperature. Step 2: Alysis of Assertion (A):
• Farmyard Manure (FYM) and compost add organic matter to the soil, promoting granular structure and soil aggregation.
• Humus formed from organic matter decomposition has a high surface area and porous structure, drastically increasing soil water holding capacity (WHC).
• Therefore, Assertion (A) is correct. Step 3: Alysis of Reason (R):
• Applied organic manure moderates soil thermal fluctuations (acts as a buffer), darkening the soil and slightly improving heat absorption, but it does NOT continuously raise bulk soil temperature by $3--4^\circ\text{C}$ in field conditions.
• Active composting piles experience heat generation due to thermophilic microbes, but once applied and incorporated into field soil, FYM moderates thermal extremes rather than elevating field soil temperature by $3--4^\circ\text{C}$.
• Furthermore, increased water holding capacity is a result of improved soil pore geometry and humic colloidal absorption, not soil warming.
• Thus, Reason (R) is scientifically incorrect. Step 4: Fil Answer:
Statement (A) is correct, but statement (R) is incorrect. Hence, option (C) is correct.
