The document discusses the significance and various aspects of drip irrigation technology in crop production, emphasizing its benefits such as reduced water losses, increased efficiency, and the possibility of fertigation. It outlines different types of drip systems, essential components, maintenance requirements, and specific management packages designed for optimal crop yields. Additionally, case studies demonstrate the economic advantages and farmer adoption experiences associated with drip irrigation practices in Sri Lanka.

1. Drip Irrigation Technology
in Crop Production
Chamila Perera
Assistant Director of Agriculture (Research) - Soil and Water Management
Field Crops Research and Development Institute - Sri Lanka

2. Content
▪ Importance of drip irrigation
▪ Different types of drip irrigation
▪ Components of drip irrigation systems
▪ Maintenance of drip systems
▪ Drip irrigation based crop
management packages
▪ Further developments
▪ Technology dissemination

3. Irrigation has the potential to provide higher yields than rainfed agriculture.
Source: FAO publications on water management
Impact of irrigation on crop productivity

4. Drip irrigation :
Supplying water to the soil very close to
the plants at very low flow rates through
emitters.
FAO Training Manual - 05

5. Benefits of drip irrigation
▪ Reduced water losses
▪ Increased water use efficiency
▪ Fertigation possibility
▪ High efficiency (labour/ energy)
▪ Land grading & leveling not required
▪ Possibility of measuring water usage
▪ User friendly operation

6. Component
Efficiency (%)
Surface Sprinkler Drip
Conveyance
40-50 (canal)
60-70 (well)
100 100
Application 60-70 70-80 90
Overall 30-35 50-60 80-90
Irrigation efficiencies

7. Different types of drip/ trickle irrigation

8. Bucket type drip irrigation

9. Low head drip irrigation

10. Drip irrigation with mulching

11. Drip irrigation under greenhouses

12. Drip irrigation under protected plant houses

13. Automatic irrigation with fertigation

14. Components of a typical drip irrigation system
▪ Water source
▪ Water pump
▪ Head controlling unit -
Filter/ Fertigation unit/ Air relief valve/ Pressure gauge/ Controlling
valves
▪ Field irrigation system

15. Drip tapes
▪ Lower cost
▪ Lesser durability
▪ Fixed emitter spacing

16. Polyethylene tubes with Inline emitters
▪ Fixed emitter spacing
▪ Higher durability compared to the drip tapes

17. Polyethylene tubes with
Online emitting devices
▪ Customized emitter spacing
▪ Replaceable

18. Technology Development
Inline drippers Inline NPC drippers Inline PC drippers
Online drippers Online NPC drippers Online PC drippers
Online PC
Self Flushing
drippers

19. ▪ Suitable for potted plants
Stake drippers

20. Other localized irrigation types

21. Bubblers
▪ Discharge - Approx. 25 - 40 LPH
▪ Suitable for orchard crops

22. Spray - jets

23. Not only the water, but also the uniform fertilizer distribution
in the root zone is very important in the fertigation
Practices.

24. Selecting the appropriate emitter type
A
B
C
0.2 bar 0.6 bar 1.0 bar
Source:
Drip
Research
Technology
Solutions
(DRTS)
PC: Pressure
compensated
Non-PC: Non pressure
compensated
PCND: Pressure
compensated non
drained

25. Water distribution in different soil types
under drip irrigation
Ideal
distribution pattern

26. Designing an appropriate layout for a drip system
- Clay soils
Planting bed

27. Designing an appropriate layout for a drip system
- Excessively well drained soils
Planting bed

28. Accessories for
the drip irrigation systems

29. Disk filters
▪ More efficient in filtration
▪ Suitable for small scale drip irrigation
Filters

30. Screen filters
▪ A commonly used filter type
▪ Suitable for small scale sprinkler irrigation systems

31. Sand media filters
Hydro cyclone flirters
▪ Suitable for large scale irrigation systems

32. Fertilizer tanks Fertigation equipments
▪ Higher durability
▪ Suitable for large scale irrigation systems

33. Venturi injectors
▪ Suitable for small scale
irrigation systems

34. Ball valves
Valve
s
▪ Release trapped air in the system
▪ Control water flow
Air release valves
Control valves

35. Other fittings

36. Maintenance of the
drip irrigation systems

37. Water source :
Agro-well
▪ Water quality
▪ Runoff blocking
▪ Cement lining
▪ Covering with nets
▪ Cleaning

38. Water class
Electrical
conductivity
(dS/ m)
Salt
concentration
(mg/ l)
Type of water
Non-saline < 0.7 < 500 Drinking and irrigation water
Slightly saline 0.7 - 2 500 - 1500 Irrigation water
Moderately saline 2 - 10 1500 - 7000
Primary drainage water and
groundwater
Highly saline 10 - 25 7000 - 15 000
Secondary drainage water
and groundwater
Very highly saline 25 - 45 15 000 - 35 000 Very saline groundwater
Brine > 45 > 45 000 Seawater
Source: FAO Irrigation and drainage paper - 48
Water quality

39. ▪ Filter cleaning
▪ Emitter cleaning
- Physically
- Chemically
- Acids - For salts (Phosphoric acid)
- Chlorination - For algae
▪ Flushing the pipes
▪ Storage in off season
▪ Security - Rodents/ Dogs
Other maintenance

40. Component
Head requirement
Bar Feet
Minimum inlet pressure 0.50 16.5
Average depth of the water table commonly observed in the
shallow wells in Sri Lanka (15 - 20 feet)
0.60 20.0
Average vertical elevation differences from the surface level of
the shallow well and the field level
0.30 10.0
For the disk filter and the venturi system in the drip system 0.30 10.0
Average head losses in the pipe system (around 50 m long) 0.15 5.0
Total dynamic head requirement of the pump at operation 1.85 61.5
Pump capacity requirement for smooth functioning of
the drip systems - Operating head & Discharge rate
The required discharge rate at the operation head is depended on the number of emitters
operated at a given time.
Ex. If 3000 of 2 LPH emitters are operated then, the required discharge is 6000 LPH.
Then, a pump with a discharge rate of 6000 LPH @ 1.85 bar pressure is most suitable for this
requirement.

41. Drip irrigation based
crop management packages
-
Experiences in Sri Lanka

42. Realizable potential yields of crops
Farmer average yields of crops
Agronomic
best
management
packages
While
conserving
natural
resources -
soil
water
Challenge

43. Increased crop productivity of crops
Fertigation
Split
application
of fertilizer
Micro
nutrients
Components of micro irrigation system based
agronomic management packages
Mulching
Raised beds
Micro irrigation - Drip systems
High yielding
varieties
Organic
matter

44. Agronomic
management
package for chilli
under drip irrigation
▪ Yields - Around 45 t/ ha of green chilli from hybrids
▪ Water productivity - 50 % increase compared to surface irrig.
▪ Labour saving - Irrigation and Weeding
▪ Energy saving in irrigation
Package
▪ Drip irrigation
▪ Cattle manure - 15 t/ ha
▪ Straw mulching - 5 t/ ha
▪ Split application of
fertilizer through
fertigation

45. Smartness in agriculture
Drip based
management
package
Water smart √
Energy smart √
Carbon smart √
Nitrogen/ Nutrient smart √
Weather smart √
Knowledge smart √
Smart Agriculture technologies/ practices

46. Case study -
Drip irrigation based chilli cultivation package
Area: Anuradhapura

47. Pick
number
Yield
(kg)
Price
(LKR)/ Kg
Income
(LKR)
1st 248 360 89280
2nd 621 380 235,980
3rd 583 450 262,350
4th 256 280 71,680
5th 378 400 151,200
6th 540 320 172,800
7th 320 260 83,200
8th 380 550 209,000
9th 365 500 182,500
10th 450 460 207,000
11th 320 550 176,000
12th 300 850 255,000
13th 270 830 224,100
14th 210 760 159,600
15th 180 700 126,000
16th 90 800 72,000
Total 5,511 - 2,677,690 USD 1 = LKR 300
Unit area: 0.25 ac
Yields and the income

48. Component LKR
Total cost 665,500.00
Total income 2,677,690.00
Profit 2,012,190.00
Profit with the
depreciated cost for the
drip system*
2,282,190.00
* The drip system will be used for 10 seasons
and thus the cost of the drip system per
season is LKR 30,000.00
Costs - Benefits
USD 1 = LKR 300

49. Yield (t/ ha) - 11 months
(35 - 40 picks)
Max. Min. Average
65 30 45
Agriculture Sector Modernization Project
- ASMP

50. Smallholder Agribusiness Partnership
Programme - SAPP
Average yield :
50 - 60 t/ ha

51. Agronomic
management
packages for onion
under drip irrigation
▪ Yields - Around 40 t/ ha
▪ Water productivity - 50 % increase compared to surface irrig.
▪ Labour saving - Irrigation and Weeding
▪ Energy saving in irrigation
Package
▪ Drip irrigation
▪ Cattle manure - 15 t/ ha
▪ Straw mulching - 5 t/ ha
▪ Split application of
fertilizer through
fertigation

52. Farmer adoption -
▪ Interprovincial Agriculture Extension Service
▪ Provincial Department of Agriculture - Central
Province
▪ Mahaweli Authority of Sri Lanka
▪ Agriculture Sector Modernization Project

53. Yala 2021 - Yala
2023
• Majority of farmers obtained - > 30 t/ ha yields
• Some have achieved - 40 t/ ha
• Average profits - > LKR 300 000/ 0.25 ac.
• Some have obtained - > LKR 500 000/ 0.25 ac.
Programme Unit area (ac.) Number
Demonstrations 0.25 28
ASMP 0.25 50
Sayubhagya 0.25 259
Sayubhagya 0.5 38
Total 375
USD 1 = LKR 300

54. Big onion true seed production under drip irrigation

55. Other crops grown -
▪ Cabbage
▪ Radish
▪ Capsicum
▪ Tomato
▪ Beet
▪ Knol khol
▪ Chilli

56. Private sector involvement
Keels Pvt. Ltd./ Cargills Pvt. Ltd.
20 different types of crops

57. Further developments

58. Water pump
Controlling unit
Soil moisture sensors
Irrigation system - Crop
Automated irrigated systems

59. Solar power for irrigation - Sustainable green energy
in agriculture
Factors to be considered -
▪ Capacity - Head/ Discharge
▪ Durability
▪ Efficiency -
• Operating under low light intensity
(DC/ Brushless)

60. Usage of the micro irrigation in the region
FAO Waters Reports - 37
Irrigation in Southern and East Asia in Figures - 2011

61. Technology dissemination strategies
▪ Field demonstrations
▪ Visits on successful farm fields
▪ Video/ Audio programmes (TV/ Radio/ You
Tube)
▪ Social media (FB/ WhatsApp groups)
▪ Leaflets/ Booklets
▪ Street drama
▪ Individual meetings with farmers
▪ Hands on training

62. Thank You