Exploring Soil Texture

By Andrea Jaggi, UNE Discovery Voyager Team Leader

The Soil Your Undies challenge is well underway and our participants have now received their Checkpoint 2 – Exploring Soil Texture email and instructions.  Even if you’re not part of the challenge, you might find the concept of soil texture rather interesting.

Texture is an essential component of soil health and exploring the physical characteristics of our soil can help us determine the influences it will have on plant growth, microbial activity and other essential processes occurring in the ecosystem. Rock, either originating as igneous, sedimentary, or metamorphic, is the source of all soil minerals and origin of all plant nutrients other than of nitrogen, hydrogen and carbon. As the parent material is chemically and physically weathered, transported, deposited and precipitated, it is transformed into a soil. Additionally, decaying organic matter like plants and animals, gases, liquid and millions of other organisms constitute the soil.

In particular soil texture influences how well nutrients are able to hold onto the, water storage and drainage. We can break soil texture down into three distinct sizes including sands, silts and clays. Particles of sand are generally quite large and can be compared to a bus in the world of soil. Next are silts, which are comparable to a basketball, and lastly, the smallest of the particles, clays. Clays are very fine particles that have a relative size comparable to a five-cent piece. Soils with a higher proportion of sand retain or absorb less nutrients and water compared to clay soils. Clay soils may be prone to waterlogging and poor drainage, where silty soils are somewhere in between.

When looking at our soils, it’s often difficult to see all particle sizes without looking closely. To observe the particle sizes of our soils, we can instead undertake a special experiment. To do this, you and your students or children will need a jar with a lid (around 250mL is a good size), a large handful of your sample soil, and a little bit of water.

We have developed a short video explain how you can undertake this experiment, as well as teacher/parent and student activity sheets. These can be found on a dedicated educational checkpoint two webpage found here.  So even if you haven’t buried any of our special Soil Your Undies undies, you can certainly do the experiment with any soil and see what happens!  Good luck.