Soil sampling instructions from the Department of Soil Science of Thessaloniki – Institute of Soil and Water Resources – HELLENIC AGRICULTURAL ORGANIZATION “DEMITRA”
http://www.ssi.swri.gr/index.php/el/services-gr-main/services-gr-3

Figure 1. The procedure of soil sampling

 

Soil sampling is based on a fundamental principle: Sample Representativeness. In other words, the soil sample to be analysed should reflect, more or less, the physico-chemical properties of a relatively larger soil area, e.g. a 5-10 acre parcel.

Soil sampling is usually carried out in the period mid-autumn to late winter and in any case before the application of fertilisers.

1. For this purpose, a field visit is carried out where soil samples are taken from 5-10 points (depending on the area of the field*) and at a depth of 0-30 cm, where the active root system of the plants is mainly developing. The sampling locations are defined by the two diagonals of the farm and are chosen randomly.
2. Subsequently, these simple samples are mixed and a quantity of approximately 2 kg of soil is taken from this composite sample, placed in a bag and forwarded to the laboratory for soil analysis.
If a soil analysis is required from a greater depth (30-60 cm), then at one of the 5-10 points mentioned above, a quantity of soil of about 1,5 kg is taken from that depth.
3. For the identification of the sample, the origin data of the sample are written on a label: Name of the producer, municipality, municipality district, location, parcel number or code number of the farm (if available), type of crop.

*In fields with an area of more than 10 hectares, we recommend that the field be divided into 2 sections and that you provide us with separate samples from each section.
It is also recommended that fields with an area of less than 10 hectares but where there is a difference in slope or soil colour should also be divided.

When sampling, skip the part of the soil that has different characteristics and if desired, create a new sample for that part of the soil. If the field is uniform throughout, then we create a sample by zigzagging across the field. If we find by eye that the field is made up of different parts, i.e. it consists of different soil types (different colour), or has a slope, or shows a difference in plant growth, then we take a separate sample for each part of the field.

Soil sampling in tree crops
Sampling positions are determined by the two diagonals of the plot and are chosen at random in the area of the crown projection of the trees, i.e. where the greatest amount of fertiliser is applied.

Figure 2. Soil sampling with a slope. Three different samples are taken and each sample includes subsamples of soil points with different slopes.

 

Figure 3. The different types of sampler: a) tube for taking undisturbed sample, b) tool for breaking large stones, c) sampler for gravel soils, d) the classic type for sampling medium consistency soils and heavy soils that have high consistency and e) sampler for light soils that facilitates sand retention.

 

Figure 4. Taking 5-10 random samples for every 10 acres by zigzagging through the field.

 

Figure 5. Procedure for unbiased reduction of the soil sample.

 

Figure 6. Representative soil sampling from an orchard. Soil sampling at the crown projection in orchards.