IRRI SERVICE LABORATORIES

provides quality and efficient integrated laboratory testing services and expertise

Soil sample preparation and submission guide

The most important aspect of soil analysis is knowing how to take a representative sample. Planning is an important step that must be done in order to address factors that need to be controlled. Sampling plan and method must be available during sampling and must be properly executed to ensure sample integrity. Results are only as good as the samples collected and the method used for its preparation. Because only a small amount of sample is used for any particular test, it is essential that sub-samples are carefully selected and thoroughly mixed, and the quantity prepared should be at least 10 times greater than the final sample analyzed.


The first consideration is the degree of urgency associated with certain analyses. For example, it may be desirable to measure pH, EC, ammonium (NH4 -N), etc., before handling the samples any further.

For pH, EC, exchangeable bases, CEC, particle size analysis, available P, K, available Cu and Zn, active Fe and Mn, organic C, Kjeldahl N, and B requiring coarse samples (<2 mm, <10 mesh):

The soil required must be air-dried, crushed, and passed through a 2-mm sieve to remove stones, twigs, leaves, stems, and roots. Dried soil should be ground to a size of 2 mm using the Rukhuhia grinder (see Facilities for Rent).

For Total C, Total N, C-13 and/or N-15 analysis requiring fine samples (<0.177 mm, <80 mesh):

The soil required must be air-dried, crushed and passed through a 0.177 mm sieve to remove stones, twigs, leaves, stems, and roots. Dried soil should be ground to a 0.177 mm size using Pascal grinder (see Facilities for Rent). Once the soil has been reduced to 0.177 mm particle size, it cannot be used for other analyses.


Place the ground sample in a paper envelope and label with the following information:

  • Sample identification and description
  • Customer name
  • Requested test parameter/s

Submit the labeled sample/s with accomplished sample ID list form.


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Soil Sample Weight Requirement.pdf

Notes:

ISL's Soil and Plant Processing Facilities are located at the 1st and 3rd floor levels of the Kenzo Hemmi Laboratory. All requests for the use of these facilities must be emailed to gqnsl@irri.org at least one week before the date of use. Include the requisition number or a scanned copy of the PR for reference on your email.

Refer to the Guidelines in using ISL Soil Processing Facilities and send an email to gqnsl@irri.org for any assistance needed.