Luke Freeman, University of Arkansas Oklahoma Beginning Farmer & Rancher Program 2013 Horticulture #2: May 11

1. Water & Irrigation
Systems for Market Farming
Luke Freeman, University of Arkansas
Beginning Farmer Workshop, May 11, 2013
Kerr Center for Sustainable Agriculture

2. Irrigation Systems at the Kerr Center

3. Sustainable System
Management
Conserving moisture on the farm
1. Organic Matter – hold more moisture
2. Mulch – trap moisture
3. Cover Cropping – build organic matter
4. Reduced Tillage – conserve moisture
5. Soil Structure – hold moisture in soil
6. Farm Landscape – capture moisture

4. Mulch
Trap moisture and feed soil biology

5. Setting Up an Irrigation System
1. Water Source 2. Pumping System
3. Filtration System 4. Distribution System

6. Water Source
• Depends on location, equipment, needs
• Access to 1.5” water/acre/week during Summer and
0.75” water/acre/week during Spring and Fall
• 1 acre inch = 27,200 gal = 11 hours at 40 gpm
1. City or Rural Water—expensive but safe and easy
– Chlorine or Chloramine may be a problem
2. Ground Water—test for contamination and filter
3. Surface Water—test for contamination and filter
– Pond, River, or Creek

7. Choosing Your Irrigation System
• Understand your crop needs and climate
– Winds and high temp in SE Oklahoma limit our use of
sprinkler irrigation
– Alabama Extension Publication (in your resources)
Drip or Sprinkler
Irrigation?

8. http://www.aces.edu/pubs/docs/A/ANR-1169/ANR-1169.pdf
Preferred Irrigation Method

9. Drip Irrigation
What is drip?

10. Drip Irrigation—Advantages
1. Reduced water use
– 25-50% water used by sprinklers
2. Less foliar disease
– foliage stays dry, no soil splash
3. Reduced weed pressure
– no water to stimulate weed growth
4. Customizable to fit your scale—if using rows
5. Does not require high pressure
– needs 20-25 psi at field entrance and 10 psi at tape
6. Easily automated—with irrigation timer
7. Can be used with plastic mulch

11. Drip Irrigation—Disadvantages
1. Economic investment
– $500-1200/acre, plus maintenance and replacement
2. Frequent maintenance
– easily cut or damaged by tools, repair leaks regularly
3. Can get in the way
– must work around or move drip tape when using tools
4. Need filtered water
– must use 200-mesh screen or risk clogging emitters
5. Set emitter spacing—match to plant spacing
6. Disposal—labor and cost
7. End of season clean up
– must be removed from field and stored

12. Sprinkler Irrigation
Lawn
Sprinklers
Impulse
Sprinklers
Micro
Sprinklers

13. Sprinkler Irrigation—Advantages
1. Wets more of root zone
– Greater width of soil being irrigated allows
root to branch out farther
2. Stimulation and washing of leaves
– Beneficial to some crops, controls aphids
3. Easier to irrigate large areas
4. Less timely set-up
5. Lower investment cost
6. Less maintenance cost

14. Sprinkler Irrigation—Disadvantages
1. Uses more water
– Evaporation loss and wind loss
2. Less precise wetting pattern
– Wetting pattern can be thrown off by wind
3. Uneven distribution of water
4. More likely to encourage disease
– Damp foliage and soil splash
5. Greater pressure requirement
– Need 50-80 psi

15. Setting Up a Drip Irrigation System
DripWorks.com
University of Florida
Publication HS1144
http://edis.ifas.ufl.edu/pdffiles/HS/HS38800.pdf
http://cdn.dripworks.com/downloads/manuals/DripPlanningGuide.pdf

16. Drip Irrigation Requirements
1. High Quality Water
– Filtered to remove particulate matter, 200-
mesh screen or sand filter
2. Pressure Control
– 20-25 psi entering the field
– 10 psi through drip tape
3. Labor
– Laying out drip tape in Spring
– Repairing lines, removing at end of season

17. Drip Irrigation Layout
Create a layout plan to estimate equipment needs
Zone
1
Zone
2
Length of drip tape?
Row spacing?
Rows per field?
Mainline/Header
Secondary
Headers
Shut-Off Valves

18. Drip Tape Equipment
Cost: $500 - $1,200 per acre (U Florida Publication)
Peaceful Valley Farm Supply
Diagrams in catalog, clear listing
Drip Works
Good pricing, customer support
Other suppliers on Kerr Center handout
http://www.kerrcenter.com/beginning-farmer/materials/horticulture/irrigation_suppliers.pdf

19. Drip Tape Set-Up
“Y” Connector
or Ball
Valve
Timer
Orbit Digital and Single
Dial Water Timer, $40
Backflow Preventer
Required when
injecting fertilizer
Flushable Filter
At least 200 mesh
Pressure Regulator
10 psi
Fertilizer Injector
optional
Connector
to Header
Brass Adapter
To connect two
male ends
Hose Saver
Use where needed
to relieve tension
on connections

20. Poly Tubing
1/2 or 3/4 inch
$75 - $85 per
1,000 ft
• Order tubing and fittings from same
supplier, ensure they match
• Use In-Line Valves to control zones
independently
• “Easy Loc” or “Power-Loc” fittings
In-Line Valve Tee Connector
Female
Starter
Fitting
Figure 8 Closure
Drip Header

21. Connecting Drip Tape to Header
1/4” Barbed
Drip Tape
Connector
1/4” Barb with
Valve
Hole
Punch
Hole Punch
Demo

22. Drip Tape
• Brands: T-Tape or Chapin
– $200 for 7,500 ft
• Thickness
– 5 min for 1 year use
– 8 to 10 mil for 2-5 years (recommended)
• Emitter Spacing
– 6, 8, 12 inch
– Match to crop spacing

23. Laying Out Drip Tape
• Rolling Out Drip Tape
– Use rebar propped on cinderblocks
or jack stands
• Ending a line of drip tape
– Line should be no longer than 350’,
check with supplier
– Purchased “Grip Sleeve Ends,”
– DIY sleeve—Demo
• Securing line of drip tape
– Fabric staple on end will secure 100 ft
– Landscape staple every 30’
– Bury drip tape “Grip Sleeve End” $10
for 50

25. Repairing Drip Tape
1. Electrical Tape—for small holes
– Wrap tape around line while irrigation on
2. Tape Coupler—for large holes and tears
– Replace line after 3 couplers used, $0.57 each

26. Removing Drip Tape
• Remove from field at end of season
• Avoid damaging—used for multiple season
• Roll up tape with Jenny or home-made reel
•
•
• Tie up rolls with zip ties or baling wire
• Store off ground to prevent rodent damage

27. Rolling Up Drip Tape
Growing For Market, Nov-Dec
2009
“Build your own drip tape winder”
by Josh Volk
Growing For Market, Jan 2008
“Winter work: Build shuttles for
rolling up drip tape” by Pam Dawling

28. Using Drip Tape Effectively
• Understand the wetting pattern
– gravity and capillary action
• Longer irrigation periods
– Thoroughly wet the root zone
– 3-5 hours per session
– 1-2 x week during Spring/Fall
– 3 x week during Summer
Sandy Soil Clay Soil

29. Using Drip Tape Effectively
• Match emitter spacing to plant spacing
– 6, 8, 12 inches
• May need two drip tape lines per row
– Crops with extensive root systems, e.g. tomatoes
• Cover row with mulch
– Prevents evaporation loss
• Fertigation can be effective delivery of fertilizer
– Liquid fish and kelp common in organics

30. Sprinkler Irrigation
When is it appropriate?
1. Need to deliver a lot of water
in short amount of time
2. Establishing cover crops in
unusually dry weather
3. Crop that tolerate wet leaves,
washing off aphids, dust
4. Early morning or late
afternoon
• Minimum wind
• High humidity
• Low temperature

31. Impulse Sprinklers
1. Good for field irrigation
2. Adjustable wetting pattern
– Unsure wetting pattern overlaps
3. Need good pressure, 50-80 psi
4. Requires durable, long hoses
5. Frequent moving, dragging hoses
6. Use rain gauge to monitor
– 1 in per session, even distribution
NOT

32. Impulse Sprinklers
Perrot Impulse Sprinkler with Five-Legged Base
Lee Valley Tools, $69 – operates under low
pressure
Cheaper options at hardware
or farm supply store

33. Monitoring Soil Moisture
• Feel the soil, dig to observe depth of moisture
– Squeeze Test
• Tensiometer
– Precise (centibars)
– Expensive
• Better to irrigate sooner than later
– Wilting plant already suffering heat stress
• Better to irrigate longer than shorter
– Frequent irrigation encourages shallow root growth
Steve
Upson
Noble
Foundation

34. Critical Moisture Periods
Leafy Vegetables (cabbage, lettuce, spinach)
Root, Tuber, Bulb Vegetables (potatoes, carrots, onions)
Fruit and Seed Vegetables (cucurbits, beans, tomatoes)
• Plant with moisture at or near field capacity
• Frequent irrigation during season
• Most sensitive between head formation and
harvest
• Require regular, even irrigation
• Most sensitive as storage organs expanding
• Carrots very sensitive to moisture stress
• Most sensitive at flowering and fruit
development
• Need constant moisture during fruit enlargement
• Moisture can be reduced as fruit enters maturing
stage
See Handout and Alabama Extension Publication

35. Summary
1. Develop a system to effectively capture
and conserve soil moisture
2. Choose an irrigation system that works
for your specific needs
– Drip tape very useful in vegetable and
specialty crop production
3. Actively monitor soil moisture and
provide water when your crops need it
the most

36. Thank You
Any Questions?