How to take a test

The correct method to take a test sample is as follows:
  1. Dig down to the correct horizon.
This is either the "O" which is the surface, or the A , B , or C horizon.
The A, B, or C horizon are found further down in the soil profile and is usually noticeable with a change of color or soil Texture.
I need 200 grams of soil to do all the required tests, mark the bag with its location and profile layer.