Getting the Dirt on DIY Soil Tests

NACC NRM’s RALF team recently attended a wonderful “Digging Deeper” workshop in Perenjori. The workshop was organised by the Moore Catchment Council and facilitated by Fiona Blackham of Gaia Permaculture.

The team were able to get hands on and experiment with a couple of simple methods for testing soil types . All soils are made up of a combination of particles of clay, silt and sand. The ratio of sand, silt, and clay in soil determines its ability to hold moisture and nutrients. Finding out what your underlying soil type is will help determine what plants will be able to grow successfully and where, and help you tweak your existing soil appropriately to make it suitable for a wider range of plants. 

  1. The bolus test:

Also known as field or hand texturing. This involves looking at the behaviour of a small handful of soil when moistened and kneaded into a ball slightly larger than the size of a golf ball or bolus and pressed out to form a ribbon between the thumb and forefinger. The behaviour of the soil during bolus formation, and the ribbon produced, enables characterisation of the soil.

(source: http://soilquality.org.au/factsheets/soil-texture )

  • The glass jar test

Using a large jar with a tight-fitting lid, fill half the jar with your soil sample, then fill the remainder of the jar with water until it is not quite full. Give it a really good shake then leave it to settle out. The sand grains will settle to the bottom within the first ten seconds, followed by the silt particles over the next two minutes. The clay will settle out last, and depending on your soil type, can take up to two weeks to fully settle! Once you have your main layers, you can easily measure (by sight) the percentages of sand, silt and clay. Any organic matter in the soil will float on the surface of the water. 

For further information about soil testing please get in contact with our Regional Agriculture Landcare Facilitators; Annabelle Garratt (E) annabelle.garratt@nacc.com.au or (P) 0448 986 879 or Lizzie King (E) Lizzie.King@nacc.com.au or (P) 0447 361 335.

Annabelle Garratt & Lizzie King – Regional Agriculture Landcare Facilitators

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