Note these instructions are a very brief snapshot to encourage samples to be taken with the best chance of representing the paddock avoiding contamination.
Sampling practice is the single most important component to getting value from soil testing, and should be taken very seriously. Accurate analysis, interpretation and precise nutrient management can only occur with a quality representative sample.
Choosing where to sample
- Avoid unusual areas, stock camps, fertilizer dump sites, dam sites, gates, troughs, trees, fence lines (old and new), old burn heaps, sheds and roadways.
- Sample varying topography (Hills and flats) separately.
- Avoid poorly drained areas and wet conditions.
- Avoid headlands.
- Ensure different fertilizer and rotation histories are sampled separately.
- Avoid dung and urine patches in pastures.
- Sample high and low yielding areas separately.
- Sampling paddocks that have had ameliorants (lime) or fertilizer applied in the past 2-3 months is likely to skew results.
Taking the sample
1. Review your required tests. If guidance is required consult your local advisor/agronomist.
2. Determine an appropriate sampling plan.
3. Ensuring a representative sample is obtained.
a) Avoid unusual areas listed above.
b) Ensure all your equipment is clean.
4. Remove debris and plant material from the soil surface.
5. Take the required number of cores, aim for at least 25 cores per site, in an appropriate pattern (see below).
6. As a general rule, 8-10 inch rows and 1-inch corer, 1 in every 8 cores should be taken on a recent seeding row furrow and the remainder between the seeding rows.
7. Pool your cores in a clean plastic bucket, breaking the soil into small crumbs.
8. Mix the sample thoroughly in the bucket.
9. Place your representative sample into soil test bags and fill to the required line.
10. Ensure your equipment and bucket is clean before moving onto your next sample.
11. Shovels are not ideal, but if using a shovel ensure the sample is consistent down to the required depth (e.g. take a slice down the side not a V shaped “hole” sample).
12. If excess sample is collected ensure the sample is well mixed before sub-sampling into the bag, try to reduce the sample to around 250-300 grams to avoid excessive postage charges.
Regular testing builds a better soil nutrient profile
A comprehensive guide to “fit for purpose” soil sampling can be found at the Fertcare website under the Soil Sampling heading https://fertiliser.org.au/fertcare/Nutrients-And-Fertiliser-Information
Different sampling patters:
d) Uniform grid