Irrigation Engineering Questions and Answers Part-7

1. The value of consumptive use may be different for different crops and different for the same crop at different times and places.
a) True
b) False

Answer: a
Explanation: Consumptive use is defined as the total amount of water used by the plants in transpiration and evaporation from soils, in specific time. So, therefore the values of consumptive use vary for different crops, and vary for same crops at different places or times

2. What is the process of a plant called, through which it leaves water?
a) Photosynthesis
b) Transpiration
c) Evapotranspiration
d) Chlorosis

Answer: b
Explanation: Transpiration is the process of the plant through which water leaves the plant, through its leaves as water vapor and enters the atmosphere.

3. Transpiration process is an integral part of the main process called photosynthesis.
a) True
b) False

Answer: a
Explanation: Yes, photosynthesis is an important process of the plant through which the plant produces carbohydrates for its growth, and it is during this process transpiration occurs as an integral process in the whole photosynthesis process.

4. Which protein in the leaf of the plant utilize carbon dioxide and produce carbohydrates?
a) Chloroplasts
b) Stomata
c) Xylene
d) Leaf

Answer: a
Explanation: Water enters the leaves of the plant through the roots, where photosynthesis happens. During this, air enters the stomata of the leaves. The protein chloroplasts present here takes the carbon dioxide in air and uses it to produce carbohydrates.

5. Total transpiration about 95% occurs during the day alone.
a) True
b) False

Answer: a
Explanation: Preparation of food, i.e carbohydrates is done during daylight alone, as photosynthesis process occurs only during sunlight. Therefore most of the transpiration occurs during the day alone.

6. On which factor does the transpiration loss also depends on
a) Available Moisture
b) Type of Soil
c) Type of Irrigation
d) Method of Irrigation

Answer: a
Explanation: Availability of moisture also affects the transpiration losses because plants transpire moisture according to its availability. That is plants transpire less moisture when moisture is scarce, and transpire more moisture when it is more available.

7. On what factor does transpiration ratio depends on?
a) Water
b) Soil
c) Air
d) Moisture

Answer: a
Explanation: Transpiration ratio is directly proportional to water requirement of the plant. So, therefore if amount of water increases the ratio increases, and if amount of water decreases the ratio decreases.

8. In transpiration ratio what type of crop is considered to be weighed, for mass of dry matter produced?
a) Marketed Crop
b) Cash Crop
c) Horticulture Crop
d) Plantation Crop

Answer: a
Explanation: Mass of dry matter is taken as the weight of the entire plant including its roots. And also sometimes only marketed crop like wheat, gram etc is weighed.

9. Given information is that total mass of water required for the growth of a plant is 285 kgs, and mass of the marketed crop is 19 kgs. Find the transpiration ratio?
a) 12
b) 16
c) 25
d) 15

Answer: d
Explanation: We have transpiration ratio (TR) = (total mass of water transpired by the plant during its growth / mass of dry matter produced)
= (285/19)
= 15.

10. A crop is being tested in the lab to its loss due to transpiration. Given that initial weight of instrument is 100 kgs, and final mass of instrument is 150 kgs. The amount of water added during full growth of plant is 70 kgs. Find the loss due transpiration when the method used is phytometer method?
a) 20 kgs
b) 15 kgs
c) 25 kgs
d) 10 kgs

Answer: a
Explanation: When phytometer method is used the formula for transpiration loss (T)
= (M1 + M) – (M2)
M1 = initial mass of instrument
M = mass of water added during full growth of plant
M2 = final mass of instrument
Therefore (T) = (100 + 70) – 150 = 170 – 150 = 20 kgs.