Guideline Index

Chapter 8: Assessing Soil Nutrients

Download Chapter

Find out: how to take soil and plant tissue samples and which labs can be trusted for testing; how to recognise symptoms of plant nutrient deficiency; and how to set up fertiliser test strips.

8.1 Introduction

Before applying fertiliser, farmers need to assess which nutrients and how much of each is to be applied to correct deficiencies, or to balance what has been removed by the farming system. Many factors must be taken into account before making the final decision.

Read more

8.2 Soil testing

Soil testing is used to work out fertiliser, lime and gypsum requirements. It’s also used to monitor changes in soil nutrient levels over time. The accuracy of soil testing depends on the following: collecting a representative soil sample, correct packaging and transportation, the laboratory standards, and the test methods used. Find out more.

Read more

8.3 Suggested soil sampling guidelines

To get the best results from soil testing it is important to collect soil samples that truly representative each farm management zone. Samples also need to be taken from the correct sampling depth, and the timing of sampling is important. Sampling along the same path through the paddock can substantially reduce the variation in the soil test results. Find out more about soil sampling and the tools required.

Read more

8.4 Plant tissue testing

Plant tissue testing is the preferred method for diagnosing trace element toxicities, deficiencies, and imbalances for plants. Plant tissue testing can also help to determine other factors including responses to fertiliser applications, and nutrient deficiencies in animals. There are many important considerations when collecting plant tissue samples including: collecting representative samples, using sampling transects, selecting the correct physiological growth stage, sampling at the right time of day, and having sufficient sample material for testing. Find out more about plant tissue testing.

Read more

8.5 Soil and plant tissue testing laboratories

A number of laboratories throughout Australia offer soil and plant testing services. For more reliable test results select a laboratory that participates in a NATA or ASPAC quality assurance program. Find out more about these programs and what this means for soil and plant tissue testing.

Read more

8.6 Visual symptoms of nutrient deficiencies in pastures

To help determine your fertiliser needs it is important to visually assess pastures in conjunction with soil testing. The main features to look for include: overall colour, the presence of weeds, poor pasture species, and if applicable, legume density and leaf size. If symptoms become apparent pasture growth may have already been reduced by more than 30%. Find out more.

Read more

8.7 Fertiliser test strips

Fertiliser test strips are useful for determining what nutrients to apply, but are less useful for determining the appropriate application rate. Test strips may be used to check results of soil tests, or as a cheap way to test soil fertility. Find out more including: how to set up a fertiliser test strip, how to select the site, how to assess test strips, and how to interpret the results.

Read more

8.8 Summary

Read more

8.9 References

Read more