In my case we had a red clay. To see how much of each component was in the soil,
- I placed a sample of soil in a glass bottle, so it filled it to about half way.
- I added water and shook it vigorously.
- I left it to settle overnight and it separated into three layers, below a layer of excess water – humus at the top in a thin dark brown layer. A large band of dissolved clay in the middle and a lower layer of sugar like sand.
- The next morning I re-shook the sample again and checked it that evening, The humus layer was thicker and the layers were more clearly defined. The clay had not completely dissolved the day before.
This was a perfect visual representation of my soil. Since my block was scraped free of top soils when they built the house, it was highly likely this sample represented the soil structure over my entire block. I would advise anyone to take 4 to 6 samples, as far away as possible from each other, to get an more accurate idea of their block because it can varey widely, especially with established homes.
Ideally you want to see equal layers of each structural element – humus, grit and clay. For root crops a little more grit and for leaf crops a little more humus.