Feature video - What is the soil food web?

Dr Elaine Ingham is an internationally recognised soil microbiologist who pioneered research into the soil food web. She has spent the last four decades continuing her research and teaching scientists and farmers about how soil organisms work together with plants.

In this video, Dr Ingham gives an in-depth explainer of the soil food web and a process called nutrient cycling.

The soil food web is the complex community of soil organisms that interact with each other, the soil parent material (which is made up of rocks, pebbles, sand, silt and clay) and plants. The four major groups of organisms that make up the soil food web are bacteria, fungi, protozoa and nematodes.

The nutrients plants need to thrive are locked up in organic matter and the soil parent material. Bacteria and fungi are capable of harvesting these nutrients and, with the help of predator organisms, converting them to plant-available forms.

When plants photosynthesise, they create simple sugars, some of which are used for plant growth and others are 'invested' into the soil as exudates that attract bacteria and fungi. This activity at the root zone draws nematodes and protozoa, which feed on bacteria and fungi. The subsequent waste of these predator organisms contains nutrients in plant-available forms.

Dr Ingham explains how farmers can harness these soil processes to generate a cycle of fertility, and dramatically reduce costs and reliance on inputs.