Question

Which of the following factors affect the net amount of water to be applied during an irrigation?
(A) moisture content of soil at field capacity (B) average moisture content of soil before irrigation (C) bulk density of soil (D) depth of soil within root zone
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (C) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Recall the standard net-irrigation-depth formula and which soil/crop factors it uses.

Answer 1

The Correct Option is C

The standard formula for net irrigation depth is \(d = \dfrac{\rho_b \times D_r \times (M_{fc} - M_{bi})}{100}\), and every term in it matters: field-capacity moisture content, the moisture present before irrigation, the soil's bulk density, and the effective root-zone depth.
All four of these together determine exactly how much water needs to be added to bring the root zone back up to field capacity.
Since none of them can be dropped from the calculation, the answer includes all four factors, option 3.