Soil Sampling Procedures

General Sampling Guidelines Take cores from at least 30 sites evenly distributed over the block or section of a block. A grid pattern should be used to determine the site locations (See Diagram). Cores should be taken from spots of average growth or poorer spots if they predominate. Remember that you are trying to get an "average" sample that is representative of the entire area. For most horticultural crops cores should be taken from 0-150 mm (0-6 in) and 150-300 mm (6-12 in) depths separately and later combined into one sample. Remove each core carefully from the sampler using a clean screw driver or similar tool and place it in a clean plastic sample bag or other suitable container. At least 30 cores should be taken from the area being sampled and placed in a clean bag or other suitable container. The more cores that are taken the more representative the sample will be.

Diagram: Recommended sampling sites for established crops - row crops

If you have more than the amount of sample required by the laboratory it will be necesary to sub-sample. Place the sample in a clean container, break up the clods and spread the total sample evenly on a clean bench. Divide the sample into four quarters, discard the two diagonal quarters and place the remaining samples in a clean container. Transfer the cores or sub-sample into a clean sample bag if you have not already done so and seal the bag. Mark the bag with the block or section name, the number of cores taken and the depth of the sample. Your samples are now ready for dispatch to the laboratory. Be sure to provide all the information requested by the laboratory processing your samples to ensure that the best possible recommendations can be made.

Sub-surface Soil Sampling
Sampling of the sub-surface soil may be required where:

• soil structural problems may exist;
• deep rooted plants are not growing well; or
• salt is suspected of being a problem.