Question

Given below are two statements:

Statement (I): Water storage efficiency becomes important when water supplies are limited or when excessive time is required to secure adequate penetration of water into the soil.

Statement (II): Water application efficiency decreases as the amount of water applied during each irrigation increases.

In light of the above statements, choose the most appropriate answer from the options given below.

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

Hint:

Think about what happens to the wasted water (deep percolation and runoff) as the applied depth per irrigation grows larger.

Answer 1

The Correct Option is A

Step 1: Recall what water storage efficiency and water application efficiency mean in irrigation engineering, since Statement I is about storage efficiency and Statement II is about application efficiency.
Step 2: Water storage efficiency compares the water actually stored in the crop root zone to the water needed there. It becomes especially important whenever the water supply itself is limited, or when the soil is slow to accept water so a long time is needed to push enough water into the root zone. This is exactly what Statement (I) says, so it is correct.
Step 3: Water application efficiency compares the water stored in the root zone to the total water actually applied at the field. If more water is applied than the root zone can hold during one irrigation, the extra water is lost to deep percolation below the roots or to runoff at the tail end of the field, so the useful fraction of the applied water drops. This means application efficiency falls as the applied depth grows larger, exactly as Statement (II) claims, so it is also correct.
Step 4: Because both statements match accepted irrigation efficiency theory, the correct choice is that both Statement (I) and Statement (II) are correct, which is option 1.