Post on 25-Mar-2020
Infiltration of Water in Drip Irrigation
Dr. Garry Grabow, PEBiological and Agricultural Engineering
June 1, 2017
Fertigation Management• Good water and fertilizer management require knowledge of
irrigation system uniformity• Deep percolation is to be avoided and is affected by:
– Irr. System uniformity– Irrigation scheduling– Rainfall
• Leaching of Nutrients/Chemicals depends on amount and form
Drip Irrigation Headworks
Media Filters
Uniformity
Poor Uniformity
Uniformity
Poor Uniformity
Uniformity
Good Uniformity – Bad timing or amount
Infiltration Rate
0.000
0.500
1.000
1.500
2.000
2.500
0 2 4 6 8 10 12 14 16
Time
Inta
ke R
ate
8
Water Holding Capacity
Which has greater porosity?
12
9
Water Holding Capacity
12
Porosity = 47.6% Porosity = 47.6%
10
Capillarity
Water
SandClay
Weight of Water
Surface Tension
Soil Hydraulic Properties
Injection Considerations
• Better to inject over whole duration of irrigation rather than in a “slug” of chemicals introduced at first of cycle-leave enough time to flush chemicals out of system
• May want to use multiple cycles
Drip Lines
Main LineDrip Lines
Manifold
Flow Meter
Filter
Chemical Tank
Valve/Pressure Regulator
From Water Supply
Main Line
Dispersion
University of Florida1
Each concentric circle is 2-hour irrigation cycle
11 Nematode Management in Commercial Vegetable ProductionJ.W. Noling, 2002
Water distribution along drip line
4‐inch emitter spacing 12‐inch emitter spacing
1 Nematode Management in Commercial Vegetable ProductionJ.W. Noling, 2002
Subsurface Drip
Subsurface Drip
3- dimensional representation
From: Malek and Peters, 2011, Wetting Pattern Models for Drip Irrigationhttp://dx.doi.org/10.1061/(ASCE)IR.1943‐4774.0000320
Wetting over Time
From: Malek and Peters, 2011, Wetting Pattern Models for Drip Irrigationhttp://dx.doi.org/10.1061/(ASCE)IR.1943‐4774.0000320
Wetted Radius
1
IA Calculator, R. D. von Bernuth
Time to % Final Radius
Each concentric circle is 2-hour irrigation cycle
11 Nematode Management in Commercial Vegetable ProductionJ.W. Noling, 2002
IA Calculator, R. D. von Bernuth
Maximum Wetted Radius
1
IA Calculator, R. D. von Bernuth