Measuring Soil Biology

Why is Soil Biology Important? | What Regulates Soil Biology? | Management and Soil Biology | Soil Evaluation of Biological Productivity

There are two approaches to measuring and monitoring soil biology. Often an economic approach is to consider a data set approach where a set of just several indicators may be measured/monitored. A more encompassing approach is a multi parametric/integrated one – where a multitude of measures/indicators would be assessed in a manner that considers the entire farming system employed. Often computer models would be included in such an approach. Technologies employed to measure and/or monitor soil biology maybe considered as either low resolution (e.g. simple earthworm counts) or more sensitive high resolution (e.g. microarray technology).

Measuring and monitoring

Its important to distinguish between measuring and monitoring in terms of soil biology and management. Measurements (direct soil biology or indicators) give on the spot numbers to be considered in terms what might be a healthy or unhealthy soil or how a management strategy effects a particular measurement/indicator in a single season.

Monitoring considers measurements or indicators but looks at them in terms of a longer term implementation of a particular farming system - this is where you would look for long term patterns/changes in soil biology and may pay more attention to factors such as climate as well as changes in soil chemistry and physical structure.

Choosing a soil biology test

When considering soil biology and what tests you might use you need to consider first: What is the need of the test? – Is it for decision support where you might be weighing up between management options, or reassurance (e.g. validation of management strategy that has already been in use). Second - What is the question being posed? -What is specific impact/effect of interest? (e.g. tillage, rotation, herbicide). Finally when choosing a test, consider what knowledge you have for a chosen method(s) – and be aware of the limitations of tests.

Soil biological tests

A vast suite of tests/indicators have been developed to measure and/or monitor a vast range of factors that relate directly to or give an indication of soil biology. These are listed below:

Once a suitable test/indicator has been chosen you will need to consider: Is the information general or specific? - this limits our interpretation of a data set and what we can actually understand from the measurements. Is there an established target value for the method(s) chosen? – e.g. healthy vs unhealthy soil – this is an area of great debate amongst farmers and scientists alike. At this stage there really are no target values for a healthy soil in regards to soil biology. These targets will be identified by using large scale scientific monitoring projects to increase data collation. Consider values/measures in a regional context (e.g.soil type and climate) relative to management. Often great variability exists between regions as to what might be considered a normal/healthy measurement relative to a particular management strategy. A healthy value in one region may well be below par in another.

Related Links

Further information about Soil Biology.

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