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1. Irrigation Concerns withinHigh Tunnel Production Systems Jerry Wright, Extension Engineer
University of Minnesota Extension
Bioproducts & Biosystems Engineering Dept
West Central Research & Outreach Center - Morris, MN
High Tunnel Workshop – December 5, 2008
jwright@umn.edu or 320-589-1711
2. Uniformity of Irrigation Water Application Irrigation Water Quality
Sedimentation, algae
Water chemistry – salinity, calcium, iron, pH
Adequate filters after water source and fertigation system
Water Compatibility with fertilizer
4. Routine Line & Filter Flushing
5. Uniformity of Irrigation Water Application Water Pressure Distribution
Along header & lateral lines
Adequate pipeline diameter to minimize friction losses
Friction loss through filters, controllers and fertigation valves
Pressure Regulator & Gages
7. High Tunnel - Soil & Plant Water Management Irrigation timing and application depth
Over watering leaches nutrients & reduces O2
Under watering affects fruit growth & quality
Know your systems application rate
Gallons per linear foot per hour
Inches of water depth per hour
8. Drip Irrigation SystemWater application rate!!!
9. Know the soil texture and drip irrigation water movement
wetted soil pattern - width & depth
May need more than one drip line per row/bed
Understand plants water needs:
Increases with Plant density and foliage size
Daily crop ET (.1 to .25 inches per day)
.3 to .7 gallons per plant per day (research very limited)
Different crops may need difference irrigation schedules
Install small control valve on each irrigated row
Plant same crop type and planting date in same row
High Tunnel - Soil & Plant Water Management
11. In-Field Soil Water Assessment
12. SOIL WATER DEFICITSforTypical Soils & Soil Water TensionsGood Range for High Tunnels - 25 to 40 centibars
13. Soil Water Monitoring Sensors
15. High Tunnel - Soil & Plant Water Management Automation of irrigation system
Manual On switch with timer shut-off
Good for small - low flow systems
Too much pressure loss for high flow rates
Full timer 7day – 24 hour control
Can control one valve or multiple valves
Many sizes available & low friction loss
16. Automatic Controllers
17. Failed Irrigation with Automatic Timer
18. Closing Comments Know your irrigation system
Learn how water moves in your soil
Do not over irrigate!!!!
Automation requires a watchful eye