1. With what type of mounting does a sprinkler irrigation network give the best results?
a) Revolving Sprinkler Heads
b) Nozzles
c) Open Pipes
d) Pipes with holes near the crop
Explanation: Generally in sprinkler irrigation system water flows with pressure in the pipes. So, sometimes the pressure may be low or high depending upon the water availability, and crop requirement. So, revolving sprinkler heads are mounted upon these rising pipes because these sprinklers can work under both high and low pressures.
2. Furrows of 150 m long and 2 m apart, have longitudinal slope of 0.5 percent are initially irrigated by non-erosive stream for 100 minutes. The stream size is reduced to 50% and continued for another 40 minutes. Determine the average depth of irrigation.
a) 50.34 mm
b) 43.56 mm
c) 47.58 mm
d) 43.84 mm
Explanation: Given L = 150 m and W = 2 m and s = 0.5%
Now we have qm = 0.6/s = 0.6/0.5 = 1.2 lps
Now q = 0.4qm = 0.4×1.2 = 0.48 lps
Average depth of water applied
= (2 x 100 x 60 + 0.48 x 40 x 60) / 1000 x (1 / 300) x 1000
= (12+1.152) / 300 x 1000
= 43.84 mm.
3. In which type of irrigation method the entire land is not wetted?
a) Furrow Method
b) Free Flooding
c) Contour Farming
d) Basin Flooding
Explanation: In this method only one half to one fifth of the surface of land is wetted so as to reduce the evaporation losses. In other methods, evaporation losses cannot be controlled properly.
4. In which irrigation method levees are provided along the contours?
a) Check Flooding
b) Free Flooding
c) Contour Farming
d) Basin Flooding
Explanation: This method is a type of ordinary flooding except water is controlled by surrounding the plots into which is divided by low and flat levees. These levees are constructed along the contours and have vertical interval of 5 to 10 cm.
5. In which method of flooding, does the water take circuitous route to irrigate the land?
a) Check Flooding
b) Zigzag Flooding
c) Free Flooding
d) Basin Flooding
Explanation: In this method, the entire land is divided into square or rectangular plots, which are subdivided with help of low bunds or levees. So, therefore the water which comes from the main ditch takes a circuitous route in each plot to irrigate the land. This is done to control the velocity of the flow of water.
6. What is the time interval between two consecutive watering called?
a) Crop Period
b) Period
c) Base Period
d) Rotation Period
Explanation: Every type of crop requires different amount of water for its complete growth in certain fixed intervals of time. The time interval between two consecutive intervals is called a rotation period.
7. What is total depth of water, for complete growth of crop called?
a) Triangle
b) Delta
c) Duty of Water
d) Rotation Period
Explanation: The total quantity of water required by the crop for its complete growth can be expressed in terms of depth of water standing on the field. This total depth expressed in cm is called delta.
8. Duty of water helps in the work out of discharge required for designing the channel.
a) True
b) False
Explanation: Duty of water gives a relation volume of water required and the area of irrigated crop. So, in this way if we know the area of crop irrigated we can know discharge required for the channel.
9. What is the name of duty called as in direct irrigation?
a) Flow Duty
b) Quantity Duty
c) Duty
d) Delta
Explanation: When direct irrigation is used, then the units of duty, always expressed in hectares/cumec. Then duty is called flow duty.
10. Which type of period is slightly more than its counterpart period?
a) Crop Period
b) Period
c) Base Period
d) Rotation Period
Explanation: Crop period is time period between the instant of sowing to its harvesting. Base period is the time period between the first watering of crop to its final watering before harvesting.