Question

Given below are two statements:
Statement (I): The sum of matric and osmotic potential is called 'hydraulic head' which is a useful index for characterizing the energy status of soil-water with respect to plant-water uptake.
Statement (II): Hydraulic potential is useful in evaluating the direction and intensity of water moving forces in the soil profile.
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:

Recall that hydraulic head normally combines gravitational and matric potential, not matric and osmotic potential.

Answer 1

The Correct Option is D

Both statements deal with the different pieces of total soil water potential, so it helps to first list what actually makes up hydraulic head before judging each claim.

1. Statement (I): this says hydraulic head is the sum of matric and osmotic potential. In practice, hydraulic head is built from gravitational potential plus matric (or pressure) potential, expressed as a height of water. Osmotic potential is left out of hydraulic head because it does not push bulk water through ordinary soil pores, it only becomes important at a membrane, such as a plant root, so this statement mixes up the components and is false.
2. Statement (II): this says hydraulic potential shows the direction and strength of water movement in the soil. This is exactly how Darcy's law works, water always flows from high hydraulic potential toward low hydraulic potential, and the steepness of that gradient tells us how strong the driving force is, so this statement is true.

Since the first claim wrongly defines hydraulic head while the second correctly describes its role in water movement, the pairing has one wrong and one right statement.

Let's summarize:

• Hydraulic head equals gravitational potential plus matric potential, osmotic potential is not part of it under normal soil flow.
• Hydraulic potential gradients set both the direction and the intensity of water movement in a soil profile.

So Statement (I) is incorrect and Statement (II) is correct, which is option 4.