Guideline Index

Chapter 9: Interpreting Soil and Tissue Tests

9.1 Introduction

The interpretation of results from soil and plant tissue tests help farmers and service providers to make more informed, cost-effective fertiliser decisions. Many field experiments have been used to verify soil and plant testing laboratory results.

Soil tests are a valuable tool for identifying the macronutrient status of paddocks on the farm. They also provide information for soil amendments to address such issues as sodicity and acidity. Although providing very important information, soil and plant tissue tests are only one piece of the jigsaw to determine the final fertiliser recommendations.

Plant tissue tests are the preferred method for diagnosing the level of micronutrient (trace element) toxicities, deficiencies and nutrient imbalances for plants. Occasionally plants can exhibit a nutrient deficiency which is not detected by a soil analysis. Research has also shown that using soil tests to indicate trace-element deficiencies can be very inaccurate; especially on acid soils.

Soil biological properties are also important to plant growth. A description of the biological properties of soils and how to measure these is discussed in Chapter 5.

Learning outcomes

This chapter will provide information about soil and plant tissue testing, allowing the reader to accurately interpret soil tests and to use the results to assist in making fertiliser decisions.