Where do I do Each Test and How Many Times per Field?

In each field you’re interested in monitoring, you need to decide where you want to sample your soil. If it’s your first time going out soil sampling, you can start with choosing one sample site in your field, with the idea that you will come back to within a 5m circular area of that spot each time you do the tests again. By returning to more or less the same spot you’re able to see how the soil is changing with time and as you change management. If you’re using the Soilmentor app, save the GPS locations of your chosen sample sites.

If you want to explore a field’s performance in more detail, you can add more sample sites in a field, for example at:

  1. The best spot
  2. The worst spot
  3. An ‘average’ spot in the field

You can choose more sample sites if you like – it’s all about how much time you have! You can also just do one sample site in a field and use that spot as an indicator site for changes in that field.

How to do a W Walk

You’ll need to know how to walk a W for some of tests, such as Plate Meter or or Sward Stick readings…

First go to a corner of your field, and walk 20 steps away from the corner towards the middle of the field. This is the start of your W.

Don’t get closer than 20 steps from the edge of your field.

Aim for the other end of the W to be in a similar spot in the other corner of the field either to your right or left.

How do I do the tests in each field?

  1. Spade and Probe Tests

For spade tests dig out a 20 cm block, digging the spade down on three sides and lever out the soil block from the dug side opposite to the undisturbed side. Try to keep the soil block as intact as possible. Put the soil block on a tray or bag and if there is any left in the pit going down to 20cm dig this out and put it on the tray too. Use the undisturbed side to do your VESS top/bottom depth assessment and don’t forget to take a photo.

2. Grass Tests

Do one grass test every one acre along your W walk (see instructions above) or a minimum of 6 grass tests, depending on how much time you have

In the Soilmentor app record information for each grass test using a sample called ‘W Walk’ for each field (this can be created as its own sample site).

For Lab Tests: Take a “Compound” Sample

In the Soilmentor app there is the option to add in lab test readings too. If you’ve created a sample for W walk tests, it can be interesting to add your lab results to this sample to compare to other W walk tests. In order to take a lab soil sample you want to get a sense of an average for the soil in that field.

Taking samples to combine into a compound sample across your W is a way to create a representative average for a whole field.

Avoid: Field margins, hedges, water troughs etc

  1. Walk a W across the field (instructions above)
  2. Take 20-25 “sub samples” more or less evenly along the way
  3. Mix sub-samples well in a bag
  4. Close bag
  5. Label bag with field name