With the help of a probe or a shovel and a bucket, remove the soil until a depth of about 17cm in 10 to 15 (or more) locations in the sampling zone by following a zigzag pattern:
A hollow probe with a 2cm diameter will be suitable for the majority of cases. In rocky or clay soil, a bored probe or auger works better;
With the shovel, first dig a hole and then take a 1.5cm thick slice, as uniform as possible, and only keep 2 to 3cm in width for that slice of soil. Always take the same volume of soil from each location;
With the help of the farm plan, design a random route to follow in the field.
Places to avoid are:
- Fertilized strips (in cases of sampling after seeding or direct seeding, etc.);
- Depressions, run-off channels and knolls (sample separately, if desired);
- Edges of fields: ditches, windbreaks, etc. (sample separately, if desired);
- Points where there is an accumulation of manure, compost, soil amendments, etc.
In order to limit all forms of contamination, the soil sample should not be handled with the hands. Clean plastic tools and containers must be used. The collected earth must be mixed with a trowel or any other small tool. Core samples (or slices) of moist or clay soil will crumble after being left to dry in the open air, spread on a piece of paper for several hours, free from dust. The sample must not be heated (oven, etc.) as this could alter the content of the mineral elements. Remove plant debris, stones, and other large bits of material and fill the pre-prepared shipping container.