James Stewart – Training & Development Manager

We all know the importance of soil testing and the valuable data it can provide for fertiliser and soil amendment recommendations. With the soil testing season in full swing and recent changes to sampling depth requirements in NA Pro, it’s important to make sure your samples are error free.

To plan your sampling strategy, consider:

  • Why the samples are being taken (monitoring, troubleshooting or budgeting);
  • Where and from what depth should samples be taken (using as much data and history as possible);
  • When the samples should be taken (time of year and soil conditions); and
  • How many cores for each sample and how many samples you need from each paddock or zone.

A fertiliser recommendation is only as good as the sample it is based on. So, taking a clean, representative sample is essential. This can be a significant challenge, given that only 500 grams of soil is sent to the lab to represent a whole paddocks, and of that a spoonful is used in the Nutrient Advantage laboratory.

Errors in sampling are the largest cause of incorrect interpretation and subsequent recommendations. The Fertcare® Soil Sampling Guide is a great resource to assist with correct sampling procedures. It’s comprehensive, covering sample timing, locations, procedures, equipment, and sample handling and dispatch. This Fertcare Soil Sampling Infographic also provides a good snapshot of accurate sampling processes.

Sampling depth

Good fertiliser stewardship means sampling to the correct depth. Tables 1 & 2 below show the soil surface and subsurface sampling depths from pages 21 & 22 of the Fertcare Soil Sampling Guide. These are the depths for which there is soil test calibration data.

Table 1: Surface soil sampling depths (cm)

Table 1: Surface soil sampling depths (cm) Source: Fertcare Soil Sampling Guide, p 21

Table 2: Sub-surface soil sampling depths (cm)

Table 2: Sub-surface soil sampling depths (cm) Source: Fertcare Soil Sampling Guide, p 22)

NA Pro – updates to sampling depth requirements

NA Pro is a Fertcare accredited system that undergoes regular audits to maintain accuracy and reliability. The NA Pro software has recently been upgraded to prevent non-standard sampling depths causing incorrect interpretations and recommendations.

When creating a new sample in NA Pro, you will notice a sample depth list in the sample details screen.

If the incorrect sampling depth is selected for the crop type you have sampled, you will be notified with a pop-up box. If you continue to log the sample without correcting the depth, NA Pro won’t produce a recommendation for that soil sample. So, for soil test results to be interpreted accurately and meaningfully, it’s important to make sure the depths of both the physical soil samples you collect, and the depths you select in the NA Pro software match the Fertcare guidelines for different crop types.

The power of NA Pro

NA Pro helps you make nutrient decisions based on accurate, timely and scientifically supported data. It allows you to:

  • Submit samples into NA Pro or the LabSTREAM app.
  • Fine-tune and refine to specific crop types, growth stages, and local conditions.
  • Run recommendations for different scenarios to make the best decision.
  • Receive interpretations of your results and automated recommendations to manage your nutrient program effectively.

NA Pro is independently accredited by Fertcare.

Agronomists who have completed IPF’s Agronomy in Practice training have full access to the software. This includes access to automated fertiliser recommendations based on scientific research and agronomic principles, allowing them to easily deliver tailored guidance on products, rate, timing and application methods to clients.

NA Pro generates three report types:

1. Lab Results Report: Displays test results for a single sample, or a summary report comparing up to five different sample results side by side.

2. Interpretation Report: Compares test results to optimum values for each crop, using traffic light bars and comments to help interpretation (see image 1)

3. Recommendation Report: Offers nutrient and fertiliser product recommendations, complete with tailored guidance on rate, timing, application methods, along with agronomic advice and commentary.

Image 1: Interpretation report generated and accessible in NA Pro.

Make your testing program count

Soil testing is an important step in making good fertiliser and soil amendment decisions, and guiding crop choice. However, errors in sampling will lead to incorrect soil test interpretation and recommendation. Use a planned sampling approach to make sure you get a representative sample – with the right number of cores from the right sample depth.

Further information

For more information about soil sampling feel free to ring me on +61 447322372 or email james.stewart@incitecpivot.com.au.

You can also contact one of IPF’s Technical Agronomists who are available to help with any queries about sample depths or soil testing across all crop types.

There is also information about NA Pro visit the Nutrient Advantage website.