drip irrigation and high tunnels

Making a Difference in Minnesota

High Tunnels and Drip Irrigation

© 2009 Regents of the University of Minnesota


Drip Irrigation Considerationswith

High Tunnel Production SystemsJerry Wright, Retired Extension Engineer

University of Minnesota Extension Bioproducts & Biosystems Engineering Dept

West Central Research & Outreach Center - Morris, MnHigh Tunnel Workshop – December 2, 2009

[email protected] or 320-589-1711


mailto:[email protected]�

Reasons for Using Drip/Trickle Irrigationin High Tunnel Production System

•Efficiently & Uniformly Applies Crop Water as Needed

– to maintain optimum growing conditions– for transplant establishment – for uniform plant/produce development

• by enhancing INPUT use efficiency– to protect & enhance yield and quality

•Effectively Applies Some Nutrients in Water


Irrigation System Needs!!!

• Water supply• System performance

– Uniform water application– Flexible & crop specific control– Fertigation?? – Frost protection??– Cooling??

• System Options• Operating Labor• Cost????• Consult Local Experts


Water Supply!!!3 to 10 gallons per minute per tunnel

Dependent on Drip Flow Rate and Tubing Layout


Estimated Daily Crop Water Use “ET” Typical Annual Crop

0.00

0.05

0.10

0.15

0.20

0.25

0.30

14-May

28-May

11-Jun

25-Jun

9-Jul23-Jul

6-Aug20-Aug

3-Sep17-Sep

ET -

Inch

es p

er d

ay

Annual water use = 8 to 18 inches© 2009 Regents of the University of Minnesota

Irrigation Water Applied in 2005Average Inches per Day

High Tunnel Tomatoes at Staples, MN

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Inch

es o

f wat

er p

er d

ay

may = 5–10 inches more than outside


IRRIGATION WATER USE PERMITMinnesota Rules

www.dnr.state.mn.us/permits/water/index.htmlIN EXCESS OF 10,000 GALLONS PER DAY(= 7 gpm)

GREATER THAN ONE MILLION GALLONS / YEAR

WITHDRAWAL LIMITS ON SURFACE WATER 6 ACRE-INCHES PER ACRE with STREAM FLOW MINIMUM

GROUND WATER LIMITS 12-15 ACRE-INCHES PER ACRE CANNOT CREATE ANY INTERFERENCE WITH DRINKING WELLS

WELL CONSTRUCTION FEE $215 (Mn Dept Health)IRRIGATION APPLICATION FEE $150 - $300(after the fact)ANNUAL REPORT ($140 minimum fee) for 50M Gallons


Water Quality Concerns??• Iron–Calcium-Sand (groundwater)• Algae – Sand – Silt (surface water)

• Water Treatment– Screen/Disc Filters, – Sand filter Tanks– Chemical treatment?????


What are the soil characteristics in the proposed site???

• Rooting potential– Restrictive layer

• Drainage limitations • Soil texture• Water holding capacity• Consult local experts

– NRCS & Extension


Know Your Soil Rooting Depth

and

How Will Water Re-Distribute!


Drip Irrigation System Options!!!


Drip Irrigation SystemCharacteristics!!!

• Low pressure & small water supply• High water application efficiency• Solid-set management

– variety of emitter spacings– Irrigate crops separately

• Moderate Labor– easily automated

• Works well with mulches – plastic

• No frost protection• Emitters’ plug easily• Tube damage


Drip Irrigation Wetted PatternDesign!!!


Line Source Drip Tape

• Tape– Emitters manufactured within the tape wall– Common spacings: 4”, 8", 12", 16", 18", 24’’– Flow rates (GPH) @ 8 psi: .16, .21, .33, .53

• .45GPM/100feet = 27 GPH/100ft or .67GPM = 40GPH/100ft.– Wall thickness (mil): 6, 8, 10, 15

• One to two year of usage– Maximum operating pressures: • 6 mil @ 10 psi– • 8 mil @ 12 psi • 10 mil @ 14 psi •15 mil @ 25 psi– ?? Pressure compensated drippers for more uniformity of

water and fertilizer applications• Surface or sub-surface installations


Line Source Drip Tubing

• Tubing (in-line emitter devices)– heavy wall thickness: 2-3 times tape– Variable spacings: 9, 12, 18, 24, 48”– multi-seasonal use

• 6 to 10 times more costly– pressure compensated dripper options for best uniformity of

water and fertilizer applications and self-flushing: dirt and debris during operation

• Surface or sub-surface installations


Table 4: Average Application Rate from Drip Irrigation Systems by Jerry Wright, Extension Engineer, University of Minnesota

Email: [email protected] (April 2005)

Drip Tube Flow ********** Wetted Soil Width in Inches *************GPM GPH 8 12 16 20 24

per 100ft per 100ft Average Application Rate - Inches per Hour0.200 12 0.29 0.19 0.14 0.12 0.100.250 15 0.36 0.24 0.18 0.14 0.120.300 18 0.43 0.29 0.22 0.17 0.140.350 21 0.51 0.34 0.25 0.20 0.170.450 27 0.65 0.43 0.32 0.26 0.220.670 40 0.97 0.64 0.48 0.39 0.320.850 51 1.23 0.82 0.61 0.49 0.411.700 102 2.45 1.64 1.23 0.98 0.82

Appl. Rate inches/hour = 12 in/ft * (GPH/100ft)/(7.48 gal/cuft * 100 * wetted width in feet)file: irrigation gallons per ET version 3e.xls

Drip Irrigation SystemWater application rate!!!


Drip Irrigation System Design ??One or Two Lateral Lines per Row


Drip Tube Placement

Plants off-set down the row


Drip Tube Placement

• Tube should be installed at same time/prior to mulch• Single-row crops:tomatoes,cucumbers, muskmelons

– Place tube 4 to 5 inches from the center or in the center• Double-row crops: eggplant, peppers and strawberries

– tube should be placed directly on the center of the bed • Placement: keep emitters up and place in a shallow

groove or buried (1-2”) to aid in keeping from shifting in the bed or fasten each end of tubing to keep straight

•Caution – avoid puncturing tube during planting/staking© 2009 Regents of the University of Minnesota

Drip Installation Prior to Plastic MulchHand or Mechanical Installation


Drip Installation Prior to Plastic MulchOn a smooth soil surface & slightly buried


Header Options


Water Supply & Pump

Air - FlushingRelease Valve

High Tunnel House

Shut of fValves

Sub-main

Tee AdapterTo Drip Tubewith Shut of f

Valve

Drip Tubes

Pressure Gauges

Pressure Regulator

Filter

ChemicalInjector

Backf low Device

Control Timer Valve

2004 Jerry Wright, University of Minnesota

Filter


Drip Irrigation SystemOperation & Maintenance!!!

• Easily damaged– Rodents, hoe,

• Emitters’ easily plugged– Iron and calcium– Sand, algae – Some fertilizers


Water Supply & Pump

Air - FlushingRelease Valve

High Tunnel House

Shut of fValves

Sub-main

Tee AdapterTo Drip Tubewith Shut of f

Valve

Drip Tubes

Pressure Gauges

Pressure Regulator

Filter

ChemicalInjector

Backf low Device

Control Timer Valve

2004 Jerry Wright, University of Minnesota

Filter

Drip Irrigation Control Assembly© 2009 Regents of the University of Minnesota

Drip Irrigation Control Assembly

Cost: $300–600 + water supply system© 2009 Regents of the University of Minnesota

Trickle Irrigation SystemZone - Design!!!


FERTIGATIONNutrient "spoon-feeding"

• Check out chemical compatibility with irrigation water• Provide backflow protection – MDA Fertigation permit?


CHEMIGATION - FertigationNutrient "spoon-feeding"

• Calibration to a daily or weekly feeding program• Assess backflow protection between water source – ?MDA Permit?© 2009 Regents of the University of Minnesota

When & How Much Should I Water????


Average Irrigation Applied in High Tunnel TomatoesGallons per Plant per Day - Staples 2005

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

15-M

ay

22-M

ay

29-M

ay

5-J

un

12-J

un

19-J

un

26-J

un

3-J

ul

10-J

ul

17-J

ul

24-J

ul

31-J

ul

7-A

ug

14-A

ug

21-A

ug

28-A

ug

4-S

ep

11-S

ep

18-S

ep

25-S

ep

2-O

ct

9-O

ct

Gal

lon

s p

er P

lan

t p

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a

Plt/dy in 18" spacing Plt/dy in 24" spacing

Poly. (Plt/dy in 18" spacing) Poly. (Plt/dy in 24" spacing)

Average Irrigation Applied in High Tunnel TomatoesGallons per Plant per Day - Staples 2005field observations indicate cucumbers can use more water


In-Field Soil Water Assessment


Soil Water Monitoring Sensors


Sensors Installation Steps

• Soak sensors in water 2-3 hours & air dry –repeat cycle 2/3 Xs

• Place in soil profile within plant row at 2 to 3 depth locations

• Mark sensor depths and site• !!! Read Sensors Frequently !!!!© 2009 Regents of the University of Minnesota

SOIL WATER DEFICITSfor

Typical Soils & Soil Water TensionsGood Range for High Tunnels - 25 to 40 centibars

Soil water tension in centibars, cbs 10 30 50 70 100 200 1500**

Soil Texture

Soil water deficit – inches per foot of soil

Coarse sand 0 0.1 0.2 0.3 0.4 0.6 0.7 Fine sand 0 0.3 0.4 0.6 0.7 0.9 1.1

Loamy sand 0 0.4 0.5 0.8 0.9 1.1 1.4 Sandy loam 0 0.5 0.7 0.9 1.0 1.3 1.7

Loam 0 0.2 0.5 0.8 1.0 1.6 2.4 **1500 cbs is approximately the permanent wilting point for most plants and the soil water deficit values equal the soil’s available water holding capacity


Installation Tips

• Soak sensors in water 2-3 hours & air dry – repeat cycle 2/3 Xs

• Place in soil profile within plant row at 1 to 2 depth locations

• Mark sensor depths and site• !!! Read Sensors Frequently !!!!

Soil Water Monitoring Sensors


Soil Water Monitoring

Irrometer Co - http://www.irrometer.com/Spectrum Technologies - http://www.specmeters.com© 2009 Regents of the University of Minnesota

http://www.irrometer.com/�

Hansen AM400 Soil Moisture Data LoggerWatermark Soil Moisture Date Logger

Automatic Soil Moisture MonitoringSave 10 to 20 minutes Each Day

$500-650


http://www.mkhansen.com/�


Extension MaterialsMinnesota High Tunnel Production Manual

http://www.extension.umn.edu/distribution/horticulture/M1218.html or http://www.mfvga.org/

Handbook –“Trickle Irrigation in the Eastern United States” NRAES #4http://www.nraes.org

High Tunnels for the Central Great Plains - Kansashttp://www.hightunnels.org/

High Tunnel Production in Pennsylvania http://plasticulture.cas.psu.edu/H-tunnels.html

Plastic Mulches & Drip for Vegetable Production North Carolina State University Extension

http://www.ces.ncsu.edu/hil/hil-33.html

Micro irrigation in Mulched Bed Production Systems: Irrigation Depths. Florida Cooperative Extension

http://edis.ifas.ufl.edu/AE049


http://www.nraes.org/�

http://plasticulture.cas.psu.edu/H-tunnels.html�

http://edis.ifas.ufl.edu/AE049�

*** Time for Questions ***


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