How to Take the Perfect Spade Soil Sample

Soil Sampling 101

Oct 21, 2020 | Soil Health

In this series of videos I will guide you on how to take the perfect spade sample. 
Taking good spade samples is essential when regularly monitoring and observing your soils.
If you are making the effort of spade sampling on your farm, it will be most useful to you if these are as consistent as possible. Making it easy to compare between different fields and with historic images. As well as making visual interpretation of the samples both possible and straightforward.

Step 1 – How to Take Your Sample

  •  Place spade vertical to the ground to ensure cubic shape of sample
  •  Jump on spade
  •  Repeat on all four sides
  •  Lever out the whole sample and place to side of hole
  •  Remove spade marks on sides of cube by tearing it in half
  •  Place this half onto tray with profile visible

How good is your spade sample?

Features of a good sample are:

  • As square shaped as possible
  • Flat base and flat face –  showing the profile clearly
  • Includes section of the sub-soil as well as top soil
    – achieved making sure the spade is in as far as it will go

       

      Examples of bad soil samples:

      Step 2 – Interpreting your Spade Sample

      Things to check for:

      •  Look for the difference between top soil layer and sub-soil layer
      •  Assess the structure and aggregation of the sample
      •  Using a ruler measure the top soil layer

      Step 3 – Handling the Soil Sample

      Breaking up the sample:

      •  Gently break off sections to reveal internal structure
      •  Tear it apart but handle as little as possible in order to inspect the shapes in the structure – blocks, crumbs etc.

       

      Step 4 – Photograph your Sample

         

        Breaking up the sample:

        •  Gently break off sections to reveal internal structure
        •  Tear it apart but handle as little as possible in order to inspect the shapes in the structure – blocks, crumbs etc.

        Step 4 – Photograph your Sample

        Take a good quality image of the sample in its tray. If it is sunny make sure to shade the soil sample (to avoid the colour change this will make to the soil thus making it possible to compare colour to samples photographed when weather is overcast).
        Remember these tips:

        • Shoot with your back to sun (ie in shade)
        • Shoot in portrait mode
        • Frame the image using the tray

         

        That’s it. Happy sampling!

        Niels Corfield