1. : The main purpose of drainage in agriculture is to:
(A) Increase evaporation losses
(B) Remove excess water and improve aeration
(C) Increase seepage
(D) Reduce transpiration
2. : Surface drainage deals with:
(A) Removal of excess soil moisture by lowering water table
(B) Removal of excess water from the land surface
(C) Addition of water to crops
(D) Storage of water in reservoirs
3. : Subsurface drainage is provided mainly to:
(A) Lower the water table
(B) Remove surface runoff
(C) Prevent erosion on slopes
(D) Control floods
4. : Open ditches and field drains are examples of:
(A) Subsurface drainage
(B) Surface drainage
(C) Tile drainage
(D) Seepage control
5. : Tile drains or perforated pipe drains are commonly used in:
(A) Surface drainage
(B) Subsurface drainage
(C) Storage reservoirs
(D) Bunding systems
6. : The main disadvantage of surface drainage is:
(A) Requires more maintenance and land area
(B) Reduces soil aeration
(C) Expensive installation
(D) No effect on crop yield
7. : The purpose of mole drains is to:
(A) Convey irrigation water
(B) Provide temporary subsurface drainage without pipes
(C) Store rainwater
(D) Increase seepage
8. : The safe depth of water table for most crops is usually considered as:
(A) 0.2 – 0.5 m below surface
(B) 1.0 – 1.5 m below surface
(C) 2.0 – 3.0 m below surface
(D) More than 5.0 m below surface
9. : The Dupuit-Forchheimer equation is used in:
(A) Irrigation duty calculation
(B) Canal seepage loss estimation
(C) Subsurface drainage design
(D) Surface runoff estimation
10. : In subsurface drainage design, Hooghoudt’s equation is used for:
(A) Estimating depth of irrigation water
(B) Determining spacing between drains
(C) Estimating evaporation
(D) Calculating seepage from canals
11. : The depth of lateral drains in subsurface drainage is generally kept at:
(A) 0.3 – 0.5 m
(B) 1.0 – 1.5 m
(C) 2.0 – 3.0 m
(D) 5.0 – 6.0 m
12. : Surface drainage is most effective in:
(A) Sandy soils with high permeability
(B) Clayey soils with poor infiltration
(C) Rocky soils
(D) Loamy soils only
13. : Subsurface drainage is best suited for:
(A) Areas with shallow impervious layer
(B) Areas with high rainfall and water table problems
(C) Steep slopes
(D) Forest land
14. : The type of drainage system most suitable for paddy fields is:
(A) Surface drainage
(B) Subsurface drainage
(C) Vertical drainage
(D) Tile drainage
15. : Vertical drainage involves:
(A) Open channels only
(B) Lowering water table by pumping groundwater through tube wells
(C) Lining of canals
(D) Construction of bunds
16. : The process of removal of salts from soil using good quality water through drainage is called:
(A) Infiltration
(B) Leaching
(C) Capillarity
(D) Seepage
17. : In subsurface drainage, envelope materials (like gravel or sand) around pipes are used to:
(A) Reduce pipe cost
(B) Prevent soil entry and clogging of drains
(C) Increase water pressure
(D) Increase discharge capacity
18. : Random drainage system is adopted when:
(A) Low-lying patches are scattered in the field
(B) Whole field is flat and uniform
(C) Land has steep slope
(D) Permanent water table is deep
19. : The parallel drainage system consists of:
(A) One main drain only
(B) Laterals and sub-laterals running parallel to each other
(C) Random open ditches
(D) Mole drains only
20. : In surface drainage, field drains usually carry water to:
(A) Subsurface drains directly
(B) Collector drains and then to main drain
(C) Irrigation canals
(D) Underground aquifers
21. : The main advantage of subsurface drainage over surface drainage is:
(A) Low installation cost
(B) Less land loss and permanent control of water table
(C) Easy cleaning and maintenance
(D) Suitable for all soils equally
22. : Mole drains are effective only in:
(A) Sandy soils
(B) Clay soils with stable structure
(C) Rocky soils
(D) Loamy soils with high organic content
23. : The typical spacing between subsurface drains in medium-textured soils is:
(A) 2–5 m
(B) 10–30 m
(C) 50–100 m
(D) More than 200 m
24. : Subsurface drainage improves crop growth mainly by:
(A) Increasing soil salinity
(B) Reducing root zone saturation and improving aeration
(C) Lowering infiltration
(D) Reducing soil fertility
25. : A combination of surface and subsurface drainage is generally used in:
(A) Arid sandy areas
(B) Saline and waterlogged soils
(C) Rocky hilly areas
(D) Paddy cultivation