Page 100 - Nutrient Management Planning Guide

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Chapter 3.3

tip

Use a reputable soil testing laboratory that uses Alberta data to determine fertilizer recommendations. Keep a copy of sample information sheets and a completed field plan of the area represented by each sample. Follow the packing and shipping instructions provided by the lab.

Information sheets, soil sample cartons, and shipping boxes are available from soil testing laboratories.

s i d e b a r

Drying Samples Prior to Shipping

If samples cannot be sent to the laboratory immediately, they can be air dried by:

Spreading out each soil sample on a clean surface •

(aluminum pans, plastic trays, etc.). Allow the sample to completely air dry at a •

temperature no more than 30°C. If desired, a fan may be used to ensure constant airflow over samples to enhance drying. Do not dry in an oven, microwave or at a high temperature. This can change the levels of some nutrients, invalidating test results, and fertilizer recommendations.

Shipping Samples

When shipping samples to the soil testing laboratory:

Fill the soil sample bags or cartons with 0.5 kg (1 lb) •

of soil. Label each container with the information specified •

by the testing facility including: date of sampling, field number, contact name and sample depth. Complete an information sheet on cropping and •

fertilizer history. Note in detail where unusual problems exist. Ensure that samples do not become contaminated •

with anything that might invalidate test results (e.g., fertilizer).

Laboratory Analyses

Consult the soil testing laboratory regarding available analysis packages. Typical soil analyses packages for surface (0 to 15 or 0 to 30 cm) agricultural soils should include soil analyses for:

extractable nitrate nitrogen • available P • available K •

extractable sulphate sulphur • soil pH • salinity (electrical conductivity) •

Nitrate and sulphate analysis should be completed for subsurface soil samples (15 to 30 and 30 to 60 cm). If high levels of NO

3

-N or available P are suspected, ask the lab to dilute the extract to get exact NO

3

– and available P levels.

Additional analyses can also be requested for:

micronutrients (boron, chloride, copper, iron, •

manganese or zinc) organic matter • texture (usually a one-time analysis) •

Information to Submit with Samples

Soil samples should always be accompanied by information about the site, cropping expectations and management. This will put soil analysis results in context and lead to relevant fertility recommendations. Some of the information that should be submitted includes:

Legal land description or location: • This information is used to make assumptions about precipitation, soil zone, organic matter content, and length of the growing season. It can also be used to identify samples sent for analysis and for field records.

Planned crop rotation: • Planned rotation is used to determine fertility and nutrient requirements, which should be based on provincial yield response curves. The planned crop rotation will have implications for nutrient management due to differences in crop nutrient demand. Fertility recommendations based on test results can be developed for several different crops. Economics can then be factored into decision-making based on recommendations.