Irrigation of Fruit Trees – Established Orchard

Sam Birrell, Netafim Agronomist

International Pink Lady Alliance Workshop, Chile

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AGENDAWater Budgets

Evapotranspiration

Crop Co-efficient

Crop Water Use

Irrigation Scheduling

When Do I Irrigate?

Monitor

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Water Budgets

Goodwin, Victorian DPI

Evapotranspiration (ETo)

Crop Co-efficient

FAO

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Crop Co-efficient

Kcb = Crop Co-efficientETo = Evapotranspiration

EAS = Effective area of shade

Crop Water Use

Goodwin et al

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Crop Water Use

Crop Co-efficient

Crop Water Use

Kcb = Crop Co-efficientETo = Evapotranspiration

EAS = Effective area of shade

1.3 X 0.4 = 0.52

0.52 X 8(mm) = 4.16 (mm)

Irrigation Scheduling

Run Time: How Long?

When do I irrigate ?

Drippers wet approximately 1/3 of the area ( W.A. )

Water contained in a 50 cm root zone ( R.Z. )

=RAW X R.Z. X W.A

=.3 X 50 X .33

= 4.9 mm

Moisture contained within the root zone or RAW of partial coverage irrigation system

When do I irrigate ?

System application rate System Application = emitter flow rate row spacing X emitter spacing

If Row spacing = 6 M Emitter output = 2.3 L/H Emitter spacing = 0.5 M 2.3 System Application = 6 X 0.5

= 0.76 mm/H

When do I irrigate ?

Run Time

Water used by the plant– = 4.9 mm

System application rate– = 0.76mm / H

No. hours to irrigate = 4.9 / 0.76 = 6.5 hours

When do I irrigate ?

Et

X

Kc

Month S O N D J F M A

Monthly Et 72 112 141 170 189 165 130 78

Crop Coefficient Kc .21 .21 .5 .6 .6 .57 .55 .5

Daily water use mm 0.5 0.75 2.3 3.3 3.6 3.3 2.3 1.3

Period between irrigations = RAW / Daily water use = 4.9 / 3.3 = 1.4 days ( every day )

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Monitor Moisture Probes

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Monitor

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Monitor

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Miscellaneous

Sub surface drip

THANK YOU