Soil Sampling Guidelines

It is important to take a correct soil sample from a field, or else the results will be skewed.

The following is guide to taking a correct soil sample:

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1. Area

   • Take one soil sample per 2 to 4 hectares (5-10 acres) to ensure adequate coverage.

2. Timing

   • Wait at least 3 months after the last application of fertilizer before taking a sample.

   • Wait 2 years after the last lime application before sampling.

   • Always sample fields at the same time of the year to ensure consistency and avoid extremes in soil conditions (e.g., waterlogged or very dry soils).

3. Equipment

   • Use a proper soil corer to collect soil samples.

   • Have a soil sample box/bag and a pen ready.

   • Fill the soil sampling box to the lid to ensure an adequate sample.

   • Label the soil box with the field number/name and advisor code (or farmer name) using a black permanent marker to avoid contamination.

4. Pattern

   • Walk in a “W” shaped path across the sampling plot.

   • Avoid sampling around gateways, muddy areas, old fences, ditches, drinking troughs, dung or urine patches, or areas where fertilizers, manures, or lime have been heaped or spilled.

5. Depth

   • Ensure soil cores are taken to a depth of 10 cm (100 mm or 4 inches).

6. Separate Samples

   • Take separate samples from areas with different soil types, previous cropping histories, slopes, drainage conditions, or persistent poor yields.

7. Sample Collection

   • Take a minimum of 20 soil cores per sample area.

   • Mix the soil cores together thoroughly.

   • Take a representative sub-sample from the mixed cores for analysis (ensure sample box is full).

By following these steps, you can obtain a reliable picture of the lime, phosphorus, and potassium needs of your farm, ensuring optimal soil health and crop productivity.