This is the second post in the Soilmentor Soil Lab Test Blog Series exploring soil lab analyses, what we can learn from them, and where to get them done. In this blog we look at soil nutrient analyses, and we’ll be exploring leaf and tissue analysis, and SOM / SOC tests in future posts. We explored soil biodiversity tests in the first post in this series, you can read it here.

We’re often asked for lab test recommendations, and although we don’t offer them directly with Soilmentor, we want to support you in choosing which tests you can learn from, and to keep building your soil health.

It’s worth noting that we don’t necessarily see these tests as essential for understanding your soil health – every system is different and many people get great results by simply observing their soil with in-field tests. It’s important to consider soil sample testing as a snapshot of your soils at one moment in time. Soils are dynamic, so we keep testing and monitoring over time to understand the full soil health picture.

There are many parameters to consider when looking at soil nutrients, and there will always be variability in what comes up in different areas of the farm. Nutrients need to be in an available form to be taken up by plant roots, and this can be hard to accurately measure. In some cases, soil nutrient tests have shown severe deficiencies, while plants growing from the same soil show optimum nutrient levels! Nutrient interactions in the soil are complex, so it’s important to look at your soil more holistically, and look for signals of soil biology and good structure, too. We find simple tests like VESS and the slake test are just as important when indicating your overall soil health, and should always be done alongside lab tests.

If you want to add your lab tests to be viewed alongside other tests in Soilmentor, this is possible for key results in the Soilmentor lab tests category. We also work with some fantastic soil advisors who help you to understand your soils and soil test results. If you’d like us to put you in touch with an advisor, let us know.

Soil nutrient analyses quantify the nutrients in your soil, suggesting which minerals and nutrients your soil may be deficient in, to inform future inputs and management. This information can help locate problem areas on your farm, and allow for more efficient fertiliser or mineral application, or cover crop plantation.

Most soil nutrient analyses will also include a pH test of your soil, as this is likely to affect the solubility of minerals and nutrients, and the activity of microorganisms. Generally speaking, a pH of 6-7 is thought to promote ready availability of plant nutrients. CEC (Cation Exchange Capacity) tests are also normally included in nutrient testing. CEC tests tell you the negative charge of your soil, which is another measure of the extent to which soil particles can attract and hold onto dissolved nutrients. Simply put, soils with a higher CEC are able to hold onto more nutrients needed for growing, although this varies depending on which nutrients you’re hoping to retain, and what proportion of nutrients your soil has in the first place!

• Yara provide a broad spectrum soil analysis package that tests for all 12 plant nutrient levels as well as pH and CEC.

• Albion Laboratory provide comprehensive soil mineral, pH and CEC analysis with a range of package options – see more here.

• Lancrop offer a wide range of soil analysis options for pH and available nutrients.

We have never personally sent soil samples to any of these companies, so we are really keen to hear people’s feedback! This list is also by no means exhaustive – if you have any good suggestions for us to add or any other feedback, please let us know at info@vidacycle.com.