Understanding your soil is fundamental to unlocking its full potential. Whether you’re a farmer chasing higher yields or a landowner managing soil health long-term. Once you’ve taken and submitted your soil sample, the next step is interpreting the report. While it might seem daunting at first, learning how to read a soil test report can lead to more informed decisions, better yields and improved sustainability.
What Is Included in a Soil Test Report?
A comprehensive soil analysis typically includes a breakdown of macro and micronutrients, soil characteristics like pH and organic matter, and sometimes fertiliser recommendations tailored to your chosen crop. Let’s take a closer look at what you can expect.
Key Nutrients in Your Report
Most nutrients will be listed in parts per million (ppm). For all nutrients except nitrogen, multiplying ppm by two gives the pounds per acre present in the soil.
Nitrogen (N)
Measured as nitrate (NO₃), the available nitrogen is calculated by multiplying the ppm figure by 0.3 per inch of sample depth. For instance, a test reading 12 ppm from an 8-inch sample (0.3 x 8 = 2.4; 12 x 2.4 = 28.8) means you’ve got 28.8 pounds of nitrate nitrogen in your soil.
Phosphorus (P)
Often assessed via Bray, Olsen or Mehlich III methods. Ideal levels are 25–35 ppm, depending on local conditions and soil pH.
Potassium (K)
Vital for plant strength and development. A good range is 165–220 ppm.
Sulphur (S)
Tested as sulphate (SO₄), which is easily leached, especially in sandy soils. Aim for 7–15 ppm.
Micronutrients
- Zinc (Zn): 1.0–3.0 ppm
- Iron (Fe): 10–20 ppm
- Manganese (Mn): 8–11 ppm
- Copper (Cu): 0.8–1.0 ppm
- Magnesium (Mg): >100 ppm
- Calcium (Ca): >1400 ppm
- Sodium (Na): 80–120 ppm (only important in saline/alkaline soils)
Other Soil Characteristics to Know
Soil pH
Measured on a scale of 0–14, with 7 being neutral. Most crops thrive between 6.2 and 7.2. Too low or high a pH can limit nutrient uptake.
Buffer pH
Only reported if your pH is below 5.8. It helps estimate the lime needed to correct soil acidity.
Soluble Salts
Indicates the risk of salt injury to plants. Values over 0.75 mmhos/cm may suggest a problem.
Excess Lime
Shows the presence of free lime, which can interfere with herbicide and nutrient availability.
Organic Matter (OM)
Reported as a percentage. Higher OM improves nutrient retention, water availability and overall soil health. Aim for at least 2.5% in arable soils.
Cation Exchange Capacity (CEC)
Represents the soil’s ability to hold and exchange nutrients. Typical values range from 13–25. Sandy soils tend to have lower CEC.
Percent Base Saturation
Closely linked to pH and CEC, this indicates the availability of key cations like Ca, Mg, K and Na. Higher base saturation often equates to better fertility.
What Next?
A soil test is more than numbers on a page — it’s a blueprint for better land management. Interpreting these results allows you to apply fertilisers with precision, correct pH imbalances, and address nutrient deficiencies before they impact your yield.
For tailored advice and accurate interpretation of your soil test results, Land Research Associates offers expert support through our Soil Surveys, Environmental Assessments, and Land Management services. Whether you’re aiming to boost yields, restore degraded land, or meet environmental compliance, our team combines in-depth scientific knowledge with practical solutions to help you get the most from your land. Let us help you turn your soil data into a sustainable, productive future.