Drip Irrigation for Trees
Drip irrigation can reduce your water use, but doing it right can be difficult. Let’s look at getting a drip irrigation system in place for your trees.
- Water needs to be clean.
- Pressure regulation is needed, usually between 10 to 30 PSI.
- To avoid toxic salt build-up around your trees emitters need to be spaced.
- Consider elevation changes.
- The drip system needs to wet a minimum of 50 percent of the tree’s root. 60 percent is optimum
- When connecting to culinary water systems use special low pressure back flow preventers.
- The drip system must meet the needs of a mature trees during the summer.
- Emitters should be above ground. This allows visual inspection to see that the system is working. It also prevents root intrusion into emitters.
Calculate the Water Use by Mature Trees
Water used or needed per tree is calculated as follows:
Gallons per Tree = 0.623 x Tee Area x Tree Factor x
Potential ET per Day / Drip System Efficiency
ET = evapotranspiration
This conversion factor is the gallons of water for every square
foot of ground irrigated with one inch of water.
Tree Area = The diameter of drip-line or crown diameter
squared x 0.7854
For example, your tree has a 10 foot diameter crown, that is
measured from drip-line to drip-line. The formula looks like this. Tree area =
10 x 10 x 0.7854 = 78.54 square feet
This factor helps adjust for trees using water at a
different rate when presented with the same conditions. Here are some examples.
- Apple, walnut, and cherry trees = 0.85
- Mature shade trees = 0.80
- Pecan, plum, peach, pear, almond and apricot trees = 0.75
- Native plants in semi-arid areas = 0.70
Drip System Efficiency
Most drip systems are between 85 and 90 percent efficient,
which is the amount of water the tree actually has applied to it.
Proper tree planting is best handled by a professional tree
care company. Drip irrigation is a very efficient way to keep your trees