Agricultural/Bioengineering Irrigation and Drainage Engineering 1 — Questions and Answers
Question 1: Which irrigation method delivers water directly to the root zone of individual plants through emitters?
- Flood irrigation
- Sprinkler irrigation
- Drip or trickle irrigation (Correct answer)
- Furrow irrigation
Correct answer: Drip or trickle irrigation
Drip irrigation delivers water slowly and directly to the root zone via emitters, minimizing evaporation and runoff for high efficiency.
Question 2: Irrigation efficiency is defined as the ratio of:
- Water applied to water evaporated
- Water beneficially used by crops to water delivered to the field (Correct answer)
- Total rainfall to irrigation water
- Soil moisture to field capacity
Correct answer: Water beneficially used by crops to water delivered to the field
Irrigation efficiency is the percentage of water delivered to a field that is actually used beneficially by crops, excluding losses to deep percolation and runoff.
Question 3: The concept of 'consumptive use' or evapotranspiration (ET) refers to:
- Water lost to deep drainage below the root zone
- Total water used by plants through transpiration plus soil evaporation (Correct answer)
- Runoff leaving the irrigated field
- Water stored in the soil profile
Correct answer: Total water used by plants through transpiration plus soil evaporation
Evapotranspiration (ET) is the combined water loss from plant transpiration and soil surface evaporation, representing the crop's consumptive water use.
Question 4: Which drainage system uses perforated pipes buried below the soil surface to remove excess water?
- Surface drainage
- Subsurface tile drainage (Correct answer)
- Mole drainage only
- Open ditch drainage
Correct answer: Subsurface tile drainage
Subsurface tile drainage uses perforated plastic or clay pipes buried in the soil to collect and remove excess groundwater, lowering the water table.
Question 5: In furrow irrigation, water is applied by:
- Flooding the entire field surface uniformly
- Flowing through small channels between crop rows (Correct answer)
- Spraying water from overhead nozzles
- Dripping water at plant bases
Correct answer: Flowing through small channels between crop rows
Furrow irrigation delivers water through small parallel channels (furrows) cut between crop rows, allowing it to infiltrate laterally into the root zone.
Question 6: Field capacity is defined as the soil water content after:
- Prolonged drought stress
- Rapid drainage following saturation has essentially ceased (Correct answer)
- Maximum plant water uptake
- Complete evaporation from the surface
Correct answer: Rapid drainage following saturation has essentially ceased
Field capacity is the soil moisture level retained after excess water has drained away following saturation, typically 2-3 days after a heavy rain or irrigation.
Agricultural/Bioengineering Irrigation and Drainage Engineering 1
Which irrigation method delivers water directly to the root zone of individual plants through emitters?