Optimization of water and nitrate
application efficiency for Citrus trees:
recommendations for irrigation and
fertigation practices
Maziar M. Kandelous
([email protected])
Barzin A. Moradi
1
Background Information
• What do we do (Objectives)?
• Why do we do what we do (The importance of the work)?
• How do we do (Methodology)?
• Who get benefits from what we do (Benefit to Citrus Industry)?
2
Objectives
• Monitor the water and fertilizer application
• Monitor the water and fertilizer leaching
• Find possible solutions for the discovered issues
• Provide recommendation to help farmers
maintaining/improving the yield while following the regulation
3
Application
• How much water we apply? Is it uniformly distributed?
• How much nutrient we apply? Is it uniformly distributed?
• What is the evapotranspiration demand? Is it uniform?
4
Leaching
• Water Balance
• Darcy Law
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Water Balance
Leaching  Irrigation  Precipitat ion
 Evapotranspiration  Change in Storage
6
Fanjet
Drip
Cumulative leaching (cm)
Water Balance
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Darcy Law
Leaching 
 K  
HB  HA

Z A B
8
Darcy Law
HB  HA

Z AB
Total head gradient
9
Darcy Law
Total head gradient
10
Darcy Law
Total head gradient
40cm
A
B
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Darcy Law
Soil hydraulic conductivity
K    K s  f  
12
Darcy Law
Ks
Soil #2
Soil #1
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Darcy Law
K    K s  f  
f 2  
f1  
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Darcy Law
15
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Just an example
Darcy Law
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Study Site
19
Results - Mandarin
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Results – Orange
21
Benefit to Citrus Industry
• Self-monitoring of water/nitrate leaching
• Monitoring of soil profile water status
• Site dependent irrigation management
• Site/Crop dependent fertigation management
22
How will industry implement
your results
• Citrus grower as end user will have better
understanding of managing their farm and
improve it (if indeed needed)
• This study will result a guideline on how to use
the available technologies to better manage
each specific orchard?
23
One thing to remember
• No one should tell you that you need to eliminate
your leaching
• Based on the quality of water you have you are
required to add more water than required to leach
the salt out of root zone
• You just want to make sure that you have no nutrient
(Nitrate) in your leaching water
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