1. Methods of Irrigation
Dr. Sailesh Prajapati

2. Irrigation--Considerations
When do you water?
How often do you water?
How much do you water?
How do you water?
Does it matter?

3. Getting Water to the Plants
Large quantities of water for successful growth
Rainfall
Inadequate
Inconsistent
Irrigation

4. Water Requirements Water loss Plant composition Consumptive water use
Transpiration
Evaporation
Evapotranspiration
Plant composition
85-96% of total plant weight is water
Consumptive water use
Evapotranspiration + plant composition
wwwcimis.water.ca.gov

5. Water Requirements Critical water use periods Soil moisture
Constant water supply
Foliage crops – uniform water
Fruit and seed crops – fruit set/maturation
Root, tuber, bulb crops – enlargement period
Soil moisture
Consider
Soil type, texture, depth
Field capacity (60% in fine soil, 40% in sandy soil)

6. Types of Irrigation Systems
Sprinkler
Surface
Flood
Furrow
Drip (Trickle)

7. IRRIGATION METHODS
a) Surface Irrigation: Just flooding water. About 90% of the irrigated areas in the world are by this method.
b) Sprinkler Irrigation: Applying water under pressure. About 5 % of the irrigated areas are by this method.
c) Drip or Trickle Irrigation: Applying water slowly to the soil ideally at the same rate with crop consumption.
d) Sub-Surface Irrigation: Flooding water underground and allowing it to come up by capillarity to crop roots.

8. 1. Surface Irrigation (Flood/ Furrow)
used in almonds, peaches, walnuts, rice, alfalfa

9. Surface Irrigation
Water is applied to the field in either the controlled or uncontrolled manner.
Controlled: Water is applied from the head ditch and guided by corrugations, furrows, borders, or ridges.
Uncontrolled: Wild flooding.
Surface irrigation is entirely practised where water is abundant. The low initial cost of development is later offset by high labour cost of applying water. There are deep percolation, runoff and drainage problems

10. 2. (a) Surface Irrigation (Flood)

11. 2. (b) Surface Irrigation (Flood)

12. 2. (c) Surface Irrigation (Flood)

13. Flood Irrigation continued…
Advantages:
inexpensive
less labor
large amounts of water leach salts
rodent control

14. Flood Irrigation continued…
Disadvantages:
land must be leveled or contoured
uses large amounts of water
water loss through evaporation
may cause disease in some crops if applied incorrectly
run off water can cause problems (silt buildup in rivers, may contain pesticides)

15. 3. (d) Surface Irrigation (Furrow)
Used in row crops such as beans, tomatoes, corn, sugar beets other vegetable crops. Similar advantages and disadvantages to flood irrigation.

16. 3. (d) Surface Irrigation (Furrow)

17. 2. (e) Surface Irrigation Furrow (Surge)

18. Sprinkler Irrigation
Many types micro-sprinklers, solid set, aluminum pipe a. Advantages: use less water, more precise amounts of water can be applied, less run off (tail water), may be used on slightly hilly land b. Disadvantages: expensive (installation, labor, filters, maintenance), salt buildup

19. Introduction:
The sprinkler system is ideal in areas where water is scarce.
A Sprinkler system conveys water through pipes and applies it with a minimum amount of losses.
Water is applied in form of sprays sometimes simulating natural rainfall.
The difference is that this rainfall can be controlled in duration and intensity.
If well planned, designed and operated, it can be used in sloping land to reduce erosion where other systems are not possible.

30. 1. (a) Sprinkler Irrigation

31. 1. (b) Sprinkler Irrigation

32. 1. (c) Sprinkler Irrigation

33. 1. (d) Sprinkler Irrigation

35. 1. (e) Sprinkler Irrigation

36. Drip Irrigation Introduction: In this irrigation system:
i) Water is applied directly to the crop ie. entire field is not wetted.
ii) Water is conserved
(iii) Weeds are controlled because only the places getting water can grow weeds.
(iv) There is a low pressure system.
(v) There is a slow rate of water application somewhat matching the consumptive use. Application rate can be as low as l/hr.
(vi) There is reduced evaporation, only potential transpiration is considered.
vii) There is no need for a drainage system.

37. Drip Irrigation
Used on specific crops, such as grapes, trees (such as almonds, cherries, peaches)
a. Advantages:
uses less water
very precise amounts as well as fertilizer
b. Disadvantages:
expensive to install, (labor, equipment, maintenance)

38. Drip Irrigation System
The Major Components of a Drip Irrigation System include:
a) Head unit which contains filters to remove debris that may block emitters; fertilizer tank; water meter; and pressure regulator.
b) Mainline, Laterals, and Emitters which can be easily blocked.

39. Components of a Drip Irrigation System
Control
Head
Unit
Wetting Pattern
Mainline
Or Manifold
Emitter
Lateral

48. Drip Irrigation (1)

49. Drip Irrigation (2)

50. Drip Irrigation (3)

51. Drip Irrigation (4)

53. Drip Irrigation--ConsiderationsB C
A inch spacing between emitters
B 12-inch spacing
C 12-inch spacing on tightly-pressed beds

54. Home Garden Irrigation Systems

55. Sprinkler Irrigation

56. Sprinkler Irrigation

57. Furrow Irrigation

58. Drip/Trickle Irrigation

59. Comparison of Irrigation Systems
Sprinkler
Worst method
Wet foliage favors disease
Splashing of muddy water spreads pathogens
Furrow
Good method
Requires heavier soil (less sandy) and a slope
Drip/Trickle
Best method
Most expensive (but still affordable)

60. When, how often, & how much to water
With sprinkler irrigation, avoid watering very late in the day
Otherwise, water whenever needed
Avoid moisture extremes (too dry / too wet)
Water often enough to keep a consistent soil moisture
From: Once a week, wet soil 6-8” deep
To: A little every day to keep the soil moist

61. Too Much vs. Too Little Water
What will happen if you don’t water enough?
Reduced productivity
Poor pollination, cracked fruit (water fluctuations)
Delay maturity
Reduce quality and yield
What will happen if you water too much?
Waste water
Waste fertilizer
Favor disease