Question

During a particular stage of the growth of a crop, the consumptive use of water is 2.8 mm/day. The amount of water available in the soil is 50 % of the maximum depth of available water in the root zone. Consider the maximum root zone depth of the crop as 80 mm and the irrigation efficiency as 70 %.
The interval between irrigation (in days) will be \(\underline{\hspace{2cm}}\) . (round off to the nearest integer)

Hint:

The interval between irrigation can be determined by dividing the effective available water by the daily consumptive use of the crop.

Answer 1

Correct Answer: 20

The total available water in the root zone is:
\[ \text{Total available water} = 80 \, \text{mm} \times 0.50 = 40 \, \text{mm}. \] The effective irrigation water is:
\[ \text{Effective irrigation water} = \frac{40 \, \text{mm}}{0.70} = 57.14 \, \text{mm}. \] The interval between irrigation is given by:
\[ \text{Interval} = \frac{57.14}{2.8} = 20.4 \, \text{days}. \] Thus, the interval between irrigation is \( 20 \, \text{days} \).