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B3.2.3 Irrigation techniquesSprinkler irrigation

Uniform application by artificial rain

Good application efficiencies (0.7 0.8)

dependent on wind, temperature, humidity

Fairly terrain independent (but design musttake terrain into account)

Can have a low labour content

But

High(ish) investment cost

High maintenance cost due to pumping

Can be complex to run

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B3.2.3 Irrigation techniquesSprinkler irrigation: Criteria

(from Cornish)

Must permit cost recovery within one to twoyears (and double investment in a short time)

Must be suitable for use on small and irregular

shaped plots

Must require only simple maintenance andtools

Have a low risk of component failure

Be simple to operate

Be durable and reliable able to withstandrough and frequent handling without seriousdamage

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B3.2.3 Irrigation techniquesSprinkler irrigation: System layout

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B3.2.3 Irrigation techniquesSprinkler irrigation

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B3.2.3 Irrigation techniquesSprinkler irrigation: Drag hose system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Sprinkler

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B3.2.3 Irrigation techniquesSprinkler irrigation: Spray pattern

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B3.2.3 Irrigation techniquesSprinkler irrigation: Spray pattern

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B3.2.3 Irrigation techniquesSprinkler irrigation: Spray pattern:

Variation in pressure

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B3.2.3 Irrigation techniquesSprinkler irrigation: Variation in pressure

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B3.2.3 Irrigation techniquesSprinkler irrigation: Solid set system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Hand move laterals

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B3.2.3 Irrigation techniquesSprinkler irrigation: Hop along system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Drag hose system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Drag hose system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Centre pivot system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Centre pivot system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Centre pivot system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Centre pivot system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Linear move system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Linear move system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Linear move system

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B3.2.3 Irrigation techniquesSprinkler irrigation: Mobile raingun

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B3.2.3 Irrigation techniquesSprinkler irrigation: Mobile raingun

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B3.2.3 Irrigation techniquesSprinkler irrigation: Appropriateness

Type Divisibility Maintenance Risk Operatorskill

Durability

Hand move 3 2 2 2 3

Drag Hose 3 4 2 3 3

Low-tech 3 4 3 3 3Perforated pipe 3 2 1 3 2

Side roll 0 2 2 2 2

Side move 0 1 1 1 1

Static gun 2 2 2 1 3

Boom 0 2 1 1 2

Traveling gun 2 1 1 1 2

Centre Pivot 0 1 1 1 2

Liner move 0 1 1 1 2

Solid set 3 3 2 3 3

Piped distribution 3 3 3 3 4

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B3.2.3 Irrigation techniquesSprinkler irrigation: Appropriateness

Type Score Crops

Piped distribution 16 All

Low tech 16 All

Drag hose 15 All

Solid set 14 Orchards

Hand move laterals 12 All

Perforated pipe 11 Soft fruit and veg

Static gun 10 Cereals, Row crops

Side roll 7 Short cereals, row crops

Traveling gun 7 Cereals, Row crops

Boom 6 Cereals, Row crops

Centre pivot 5 Cereals, Row crops

Linear move 5 Cereals, Row crops

Side move 4 Cereals, Row crops

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B3.2.4 Irrigation techniquesMicro irrigation

Excellent efficiency (>0.9)

little and often- plants have ideal water allthe time

As little as 30% of the root zone is wetted Not sensitive to slope

Good for mineralised water

Good for injected fertiliser

But

Very expensive

Needs well filtered water

Can be complex to operate ands maintain

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B3.2.4 Irrigation techniquesMicro irrigation: Improvements

Crop Yield Increase (%) Water saving (%)

Bananas 52 45

Grapes 23 48

Sweet lime 50 61

Pomegranate 98 45

Papaya 75 68

Tomato 50 39

Watermelon 88 36

Okra 16 40

Cabbage 2 60

Chillies 44 62

Sweet Potato 39 60

Beetroot 7 79

Radish 2 77

Sugar cane 33 56

Cotton 26 53

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B3.2.4 Irrigation techniquesMicro irrigation: Layout

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B3.2.4 Irrigation techniquesMicro irrigation: Drip irrigation

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B3.2.4 Irrigation techniquesMicro irrigation: Root zone

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B3.2.4 Irrigation techniquesMicro irrigation: Infiltration

Sandy soil Clay soil

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B3.2.4 Irrigation techniquesMicro irrigation: Emitters

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B3.2.4 Irrigation techniquesMicro irrigation: Thick walled drip hose

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B3.2.4 Irrigation techniquesMicro irrigation: Thin walled drip hose

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B3.2.4 Irrigation techniquesMicro irrigation: Bubblers

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B3.2.4 Irrigation techniquesMicro irrigation: Microsprinklers

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B3.2.4 Irrigation techniquesMicro irrigation: Microsprinklers

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness

Type Divisibility Maintenance Risk Operatorskill

Durability

Drip emitters 3 3 1 1 1

Drip hose (thick) 3 3 1 1 1

Drip hose (thin) 3 3 1 1 1

Micro sprayers 3 3 2 1 3

Pressurised bubbler 3 3 3 3 4

Gravity fed bubbler 3 3 3 1 2

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness

Type Score Crops Cost (USD1990)

Piped distribution 16 All 800

Low tech Sprinkler 16 All

Pressurised bubbler 16 Orchard 3,000

Drag hose Sprinkler 15 All 675

Solid set Sprinkler 14 Orchards 3,500

Hand move laterals Sprinkler 12 All 675

Micro sprayers 12 Orchard, Soft fruit and 3,500

Gravity fed bubbler 12 Orchard 3,500

Perforated pipe Sprinkler 11 Soft fruit and vegetables 800

Static gun Sprinkler 10 Cereals, Row crops 950

Drip emitters 9 Wide row fruit and vegetables 3,500

Drip hose (thick) 9 Wide row fruit and vegetables 5,000

Drip hose (thin) 9 Wide row fruit and vegetables 3,000

Side roll Sprinkler 7 Short cereals, row crops 1,500

Traveling gun Sprinkler 7 Cereals, Row crops 1,500

Note:Skilled workers wages in Sri Lanka $4/day, Uganda, $2.5/day

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness:

Methods based on imported components

Manufactured drip emitters andmicrosprayer assemblies are carefullysupervised and maintained.

Ancillary equipment such as screenand media filters, metering valves,pressure regulators and fertilizerinjectors are used in various

combinations.

Note: These options will be justified only for cash crops in astable market economy.

From Small-scale irrigation for arid zones; Principles and options:http://www.fao.org/docrep/w3094e/w3094e00.htm

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness:

Methods based on imported materials butlocal fabrication

Moulded plastic pipes or extruded plastictubing are perforated manually and laid

over the ground to simulate dripirrigation.

Vertical sections of plastic pipes (or evendiscarded plastic containers such as

bottles) are embedded in the ground.

Thin-walled plastic vessels are filled withsand or gravel to provide mechanicalresistance to crushing.

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness:

Methods based on imported materials butlocal fabrication

Slit plastic sleeves cover the perforatedsections of the tubes to prevent root

penetration into the outlet holes.

Sand filters prevent suspended particles oralgae from clogging the outlets.

Auxiliary containers are used to dissolve andinject fertilizer into the irrigation water.

Vertical standpipes are used to deliver waterfrom an underground pipe to small basins.

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness:

Methods based entirely on local materialsand workmanship

Low-fired porous ceramic pots areplaced on the surface or embedded in

the soil within the root zone. Whenfilled with water and dissolvedfertilizers, the permeable clayreceptacles ooze water and nutrients

into the soil. Sectioned ceramic pipes constitute line

sources that feed elongated beds.

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B3.2.4 Irrigation techniquesMicro irrigation: Appropriateness: Clay

pot method

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B3.2.4 Irrigation techniquesModern irrigation technologies:

Appropriateness(from Cornish)

The technology must offer the farmersufficient financial return or a

reduction in labour demand, to justifythe investment

Farmers need to grow high valuecrops for an assured market in order

to cover costs Increasing national or regional water

shortage is an important factormotivating governments to promotethe use of modern irrigationtechnologies

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B3.2.4 Irrigation techniquesModern irrigation technologies:

Appropriateness

Governments must enact policiespromoting the technologies for the

smallholder, making it attractive tomanufacturers and dealers to developand promote them

Suitable systems must be relatively

cheap and straightforward to operateand maintain

Farmers require effective technicalsupport in the initial years failure =ruin