Soil Composition and
Hydraulic Conductivity
Irrigation Tip
Technical Bulletin Series
Why is it Important to know the
Sand-Silt-Clay % Mix
Before suggesting an
Irrigation Design & Schedule?

Guessing doesn't get us close!

The most critical aspect of soil composition is its' Hydraulic Conductivity, or the rate at which water will flow through the soil when that soil is saturated.

Within each of the twelve Soil Composition Groups the Hydraulic Conductivity Rate [HCR] varies as much as 1,000% and more.

Yes, the flow rate within the "Silty Loam" group varies from 0.07 in/hr to 1.20 in/hr (that is a 1,714% variance).
Obviously we need to get closer than just identifying the soil composition group, if we want to accurately plan our irrigation application rate and run time.

Without accuracy, we have no chance of predicting how deep water moisture will permeate a soil during an irrigation.

Preventing unnecessary evaporation is key to reducing wasted water during lasndscape irrigations. Moisture needs to be deep
(6 to 12 inches) in order to shield moist soil from evaporation

Shallow watering creates shallow root systems that need more frequent irrigations

The single most important aspect towards healthy plants is building healthy root systems!

The two most critical aspects for plants having a healthy & vibrant root system; are the type of soil they are growing in, and how that soil is irrigated.

It matters a lot that
Moisture is 12 inches deep
not 5 or 20 inches

Guessing at the rate of moisture movement in a soil may be a popular method for some to design the drip emitter layout and schedule watering intervals.

It is not a professional or successful method. The only way the "guess" method works is with luck!

A poorly designed irrigation system often produces results like this
Look at the difference between these two plants!

This same genus & species is thriving with proper irrigation designed for the existing soil composition. You can see how, even though drought tolerant, they benefit greatly from proper irrigation that produces large healthy root systems.

An Irrigation System designed
to match soil composition

Provides healthy root systems
for healthy plants

Deep moisture protected from evaporation
Easily saving 30% of landscape water use!

These are the reasons that the
Irrigation & Soil Calculators
Sand-Silt-Clay % Mix

Proper irrigation means much more than being frequently watered!
Two critical parameters of a healthy root system is their depth and spread.

Soil Settlement (Jar) Tests take about 5 minutes to complete. If you have a larger landscape, and the composition varies - it is advisable to perform a Jar Test in another area.

A convenient way to save these the Test Reults is to perform a "print-screen" following the completion of the Jar Test Analyzer.

It's not difficult to find out
which type soil composition
you have - as well as
the Hydraulic Conductivity Rate