Soil biodiversity

What is biodiversity? Biodiversity has different meanings depending on the situation being discussed and the target audience. For example, the Oxford English Dictionary defines biodiversity as being "The variety of plant and animal life in the world or in a particular habitat". This is definition is clearly sufficient for non-specialists. However, when looking more specifically at biodiversity, it becomes evident that thought needs to be given to other groups such as fungi, bacteria and archea. As soil is such as diverse system when considered biologically (as well as physically or chemically)