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 gathering soil data on your farm, it will be most useful to you if your spade samples are as consistent as possible. This will make it simple to compare between different factors such as: different fields and to historic images. As well as making visual interpretation of the samples both possible and straightforward.

 

Here’s how it’s done: Step 1

  • 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 by putting extra weight onto the spade at the end

 

Examples of bad soil samples:

Interpreting your spade sample: Step 2

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

Handling the soil sample: Step 3

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.

 

Niels Corfield