Guideline Index

Chapter 5: Understanding and Managing Soil Biology

5.6 Measurement of soil biology

Currently there are relatively limited options for commercial testing for soil biology.

Some tests assess microbial populations using direct observation via microscopy while, more recently, tests employing phospholipid fatty acid assays have become commercially available. While these tests provide some insight into soil biological populations, understanding of how to use this information is currently limited.

More sophisticated analytical tools using the science of genomics to target microbial genes to determine the functions that are active, or are potentially active in a soil, are being used to address R&D hypotheses. Testing for genes involved in the nitrogen cycle provides an insight into the potential nitrogen mineralisation or immobilisation that might occur in a given soil (Hayden et al, 2010). These tests can also show the presence or absence of genes involved in disease expression or control.

The future of soil biological testing is likely to focus on short term information relating to the potential for a soil to support efficient nutrient cycling for the coming season, or to the risk associated with pest or disease pressure. Longer term monitoring will reveal patterns in microbial community structure and function, the management of which will be aligned with recommended management practices. For example, biological testing may provide specific information on the effects of tillage, crop rotation, residue management, nutrient availability, or the use of a particular biocide. Such information will require calibration for different soil types and different climatic zones, but will be important for management and investment decisions.