Micro-irrigation

This year we knew we would have to do something different with irrigation management.  Last year we struggled to make sprinkler systems work in the outdoor garden and the high-tunnel.  Given the extreme temperatures and lack of rain, evapo-transpiration rates were great enough that is was hard to keep up with water demand using a relatively conventional sprinkler (i-WOB nozzle on a 6' stand).  In the high tunnel, the same set-up created nonuniform patterns due to droplet contact with the plastic cover.  This led us to look into micro-irrigation.

Micro-irrigation can take several forms; individual emitters, emitter tubing, spray tip, rotors, and more.  It is help to determine what plant species will be grown, then study the growth habitat of that species.  Factors such as height, width, root system, radiant tolerance, and spacing requirements will help determine the proper system and emitter type to ensure a successful system.



Individual emitters were used on the windbreak.  That is because the trees and shrubs were spaced relatively far apart and spacing varied between 6'-8'.

 

Emitter Tubing


For the garden area, I researched emitter tubing and determined that this would be the best fit for that setting.  Emitter tubing as built-in emitters into the wall of the tubing at set intervals.  It also delivers a designed rate of water out of each emitter.  I went with a tubing that has an emitter spacing of 12 inches and is designed to allow 1 gallon of water per hour to flow through the emitter. 

Two zones were created to facilitate the two different management zones; outdoor and high tunnel. 

Three main benefits:
1) Water savings- By accurately placing the water at the base of the plant, maximum water is available for root uptake.
2) Pest and weed management- Reduced pest and weed pressures from no longer watering between the rows.  This should greatly reduce competition for the vegetables and time spent weeding.
3) Ease of use!

  Our entire garden was planted with seed this year, rather than using transplants.  I'm attempting to record the hours of irrigation operation in order to get a better handle on water use and savings.  For germination, I run each zone for about one hour every other day.  As the plants mature, I plan to run the system less often, but for longer periods; possibly 4 hours each zone twice a week.  This will help establish a healthy and greater root system by moving the water down deeper into the soil profile.  Actual irrigation will be determined by a combination of the feel method and appearance of plant vigor.