Frequency of Irrigation

Q. Consider the following data:
Consumptive use = 2.8 mm/day
Root zone depth = 8 cm
Irrigation efficiency =65%
Readily available moisture = 80% depth of root zone
The frequency of irrigation will be __________ days.

1. 22

Q. A soil stratum $40cm$ deep with field capacity, wilting point and dry density $25\%$, $10\%$ and $1.5gm/c{m}^3$ respectively is grown with a crop having consumptive use requirement of $0.6mm/day$. If the soil is initially at field capacity , the number of days after which irrigation is required will be _____.

1. 150

Q. In a cultivated area, the soil has porosity of 45% and field capacity of 38%. For a particular crop, the root zone depth is 1.0 m, the permanent wilting point is 10% and the consumptive use is 15 mm/day. If the irrigation efficiency is 60%, what should be the frequency of irrigation such that the moisture content does not fall below 50% of the maximum available moisture?

1. 5 days
2. 6 days
3. 9 days
4. 11 days

Q. Consider the following statements:
Irrigation water has to be supplied to the crops when the moisture level falls
1. Below field capacity
2. To wilting point
3. Below wilting point
Which of these statements is/are correct?

1. 1
2. 2 only
3. 3 only
4. 2 and 3

Q. During a particular stage of the growth of a crop, consumptive use of water is 2.8 mm/day. If the amount of water available in the soil is 25% of 80 mm depth of water, what is the frequency of irrigation?

1. 9 days
2. 13 days
3. 21 days
4. 25 days

Q. During a particular stage of the growth of a crop, consumptive use of water is 3 mm/day. If the amount of water available in the soil is 25 % of 100 mm depth of water. The frequency of irrigation is ____ (days).

1. 25

Q. The following data were recorded from an irrigated field:

1. Field capacity : 20%
2. Permanent wilting point : 10%
3. Permissible depletion of available soil moisture : 50%
4. Dry unit weight of soil : 1500 kgf/m${}^3$
5. Effective rainfall : 25 mm

Based on these data, the net irrigation requirement per metre depth of soil will be

1. 75 mm
2. 125 mm
3. 50 mm
4. 25 mm

Q. The consumptive use of water for a crop during a particular stage of growth is 2.0 mm/day. The maximum depth of available water in the root zone is 60 mm. Irrigation is required when the amount of available water is 50% of the maximum available water in the root zone. Frequency of irrigation should be

1. 10 days
2. 15 days
3. 20 days
4. 25 days

Q. The following data pertains to healthy growth of a Crop:
1. Field capacity of soil = 32%
2. Permanent wilting point = 11%
3. Density of soil = $1500kg/m^3$
4. Effective depth of root zone = 75 cm
5. Daily consumptive use of water for the given crop = 12 mm
For healthy crop growth, moisture content must not fall down to 20% of the water holding capacity between the field capacity and the permanent wilting point, then the watering interval (in days) is

1. 12
2. 17
3. 15
4. 16

Q. A soil has a field capacity of 23% and wilting coefficient of 11%. The dry unit weight of soil is 1.5 gm/cc. The root zone depth is 70 cm. Irrigation water is applied when moisture content falls to 15%. If the water application efficiency is 75%, the water depth required to be applied on the field is _____ (cm)

1. 11.2