1. Use a soil probe to collect the soil sample.
2. Collect samples for a soil fertility test from a depth of 0-8″ for analysis of all nutrients. Collect a subsoil sample between 8-24″ or 8-36″ for residual nitrate analysis. For a herbicide residue test, collect a sample from 0-5″ depth.
3. Collect soil samples in a plastic pail to prevent contamination with zinc and other micronutrients.
4. A good sample should not represent more than 60 acres if the field is uniform, or 20 acres if the soils are quite variable. The soil sample should consist of 10-15 soil cores taken at random throughout the area being sampled.
5. Sample the field according to soil type or name. If you do not know the name of the soil type, the county extension service or NRCS offices have maps showing soil types on the farm. If the soil type cannot be determined, sample areas separately that differ in texture, color, slope, depth, or vary with respect to crop yields and fertilizer history. Areas such as eroded hill tops, dead furrows, alkali spots, terraces, old fence lines, fertilizer bands, etc., should not be included in the sample or can be sampled separately.
6. If samples cannot be sent to the laboratory immediately, allow the soil to air dry for 24-48 hours before placing in a sample bag. Do not place moist soil in a sample bag and allow it to be exposed to high temperature (for example, dashboard of a pickup, heat vent in a house, etc.) for extended periods of time. Send a minimum of one pound of soil to the lab for testing.
7. Wrap securely for mailing. A soil sample submittal form should accompany the samples. Please call the laboratory for a supply of these forms.
8. Soil sample probes can be purchased from American Laboratory.