Tech Tuesday: How to take the Perfect Sample

So you’re sampling your soil, but where to start?? Here’s our handy tips and tricks for soil sampling (especially when you’re using a PES Technologies ERU!)

Planning sampling sites

• Make sure the sites/fields you are sampling have a wide range of characteristics e.g. multiple soil types, high and low yield etc. It is useful to note this when recording data.
• Each field or area you sample should have a ‘reference’. This is an area that has not been cultivated and therefore will show the soils capabilities when not agriculturally modified. We recommend underneath a hedgerow. 

Soil Sampling

1. Choose the location you wish to sample. Remember to take notes of the conditions and context of the location e.g., soil type, cropping system etc.,
2. Take a note of your location using GPS or an app such as What Three Words.
3. Clear a small area of vegetation if present.
4. With an auger or spade take a sample to a depth of up to 15cm, removing the top 5cm. 
5. Place the sample into a bucket and mix to homogenise, breaking up large clods, remove large rocks/stones or roots.
6. Place the sample in a labelled and sealable bag, with the farm/organisation name, sample name and replication e.g., One tree farm, B3. Do not evacuate all the air in the bag, the microbes within the soil will need a small amount of air even within refrigerated hibernation to survive.
7. Remove the residual soil from the bucket and tools before taking another sample.
8. Get the samples to a refrigerator at 4°C as quickly as possible, using an insulated cool bag in the meantime.

Storage

Soil samples should be kept at 4°C +/- 1°C which places the microbial community into hibernation, keeping the soil and its properties in its current state.  This is especially important for biological and nitrogen testing.

1. Make sure the fridge you are storing your samples in is programmed for 4°C and there is no ice forming anywhere in the fridge. Ideally use fridges with forced air circulation.
2. Maintain air flow by keeping in shelves and not piling the samples too high on top of each other.
3. Do not push out all the air from the sample bags or vacuum seal them. The microbes within the soil need a small amount of air to survive, so keep a bit of air within the sample bag.

Wanting some more in-depth info? Head to our How to guides