Water & IrrigationSystems for Market Farming

Luke Freeman, University of ArkansasBeginning Farmer Workshop, May 11, 2013

Kerr Center for Sustainable Agriculture

Irrigation Systems at the Kerr Center

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

MulchTrap moisture and feed soil biology

Setting Up an Irrigation System

1. Water Source 2. Pumping System

3. Filtration System 4. Distribution System

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

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?

http://www.aces.edu/pubs/docs/A/ANR-1169/ANR-1169.pdf

Preferred Irrigation Method

Drip IrrigationWhat is drip?

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

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

Sprinkler Irrigation

Lawn Sprinklers

Impulse Sprinklers

Micro Sprinklers

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

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

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

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

Drip Irrigation LayoutCreate 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

Drip Tape EquipmentCost: $500 - $1,200 per acre (U Florida Publication)

Peaceful Valley Farm SupplyDiagrams in catalog, clear listing

Drip WorksGood pricing, customer support

Other suppliers on Kerr Center handouthttp://www.kerrcenter.com/beginning-farmer/materials/horticulture/irrigation_suppliers.pdf

Drip Tape Set-Up“Y” Connector

or Ball Valve

Timer

Orbit Digital and Single Dial Water Timer, $40

Backflow PreventerRequired when injecting fertilizer

Flushable FilterAt least 200 mesh

Pressure Regulator10 psi

Fertilizer Injectoroptional

Connector to Header

Brass AdapterTo connect two male ends

Hose Saver

Use where needed to relieve tension on connections

Poly Tubing1/2 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

Connecting Drip Tape to Header

1/4” Barbed Drip Tape Connector

1/4” Barb with Valve

Hole Punch

Hole Punch Demo

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

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

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

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

Rolling Up Drip TapeGrowing 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

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

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

Sprinkler IrrigationWhen 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

Impulse Sprinklers1. 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

Impulse SprinklersPerrot Impulse Sprinkler with Five-Legged BaseLee Valley Tools, $69 – operates under low pressure

Cheaper options at hardware or farm supply store

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 UpsonNoble Foundation

Critical Moisture PeriodsLeafy 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

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

Thank You

Any Questions?