How to take soil samples
The results of a soil analysis are only as good as the sample on which it is based. To give reliable advice, a soil sample must be representative of the area sampled and be taken to a uniform depth (10cm).
The principle of soil analysis is to determine the average nutrient status of an area and to give a measure of the available nutrients in the soil. A sample normally consists of 0.25 – 0.5 kg of soil and this is taken to represent the entire sampling area or field.
- To take a soil sample it is essential to have a suitable soil corer
- Ensure soil cores are taken to the correct sampling depth of 100 mm (4”)
- Take a soil sample every 2 to 4 ha. (5-10 acres)
- Take separate samples from areas that are different in soil type, previous cropping history, slope, drainage or persistent poor yields
- Avoid any unusual spots such as old fences, ditches, drinking troughs, dung or urine patches or where fertiliser / manures or lime has been heaped or spilled in the past.
- Do not sample a field until 3 to 6 months after the last application of P and K and 2 years where lime was applied.
- Take a minimum of 20 soil cores, mix them together, and take a representative sub-sample for analysis, making sure the soil sample box is full.
- Take a representative soil sample by walking in a W shaped pattern across the sampling area.
- Sample fields at the same time of the year to aid comparisons of soil sample results and avoid sampling under extremes of soil conditions e.g. waterlogged or very dry soils.
- Place the soil sample in a soil box to avoid contamination and write the field number and advisor code on the soil box with a black permanent marker.
Soil Sampling Pattern
