Question

Given below are two statements, one is labeled as Assertion (A), and the other one is labeled as Reason (R).
Assertion (A): The water requirement of Rice varies from 100 to 200 cm.
Reason (R): Water requirement varies due to soil type and rainfall and variety.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Rice has the highest water requirement among cereals (100–200 cm), but sugarcane has an even higher requirement (150–250 cm) due to its longer growing period.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Crop water requirement (WR) is the total depth of water needed by a crop for healthy growth and transpiration during a specified period under field conditions.
It includes water lost through evapotranspiration, percolation, seepage, and water required for land preparation.
Rice (*Oryza sativa*) is a hydrophytic crop with a high water requirement compared to other cereals.

Step 2: Detailed Explanation:
Assertion (A): Rice is typically grown under flooded or submerged conditions.
The total water requirement for rice is high, generally varying from 900 mm to 2500 mm (90 to 250 cm), with a widely accepted average range of 100 to 200 cm under typical Indian climatic conditions.
This includes water required for nursery preparation, transplanting, and maintaining standing water during the vegetative and reproductive phases. Thus, Assertion (A) is correct.
Reason (R): The exact water requirement of rice varies across different locations.
This variation is driven by:
- Soil type: Sandy soils have high percolation losses, increasing water requirements, whereas heavy clayey soils retain water well, reducing percolation.
- Rainfall: Effective rainfall directly contributes to crop water needs, reducing irrigation requirements.
- Variety: Short-duration varieties require less total water than long-duration varieties.
This variability in environmental and biological factors directly explains why the water requirement of rice spans a wide range (100 to 200 cm).
Therefore, both statements are correct, and (R) is the correct explanation of (A).

Step 3: Final Answer:
Both statements are correct, and (R) is the correct explanation of (A).