Since it is my scientific field (in a broader view) I have invested some effort and set up a very graphical presentation featuring soil and soil microbiology. The presentation is freely available at the Helmholtz-Centre for Environmental Research (UFZ) in Leipzig, Germany. Here comes a short summary of the various chapters. Each of them will be described in more details in subsequent posts.
Chapter 1 describes the physicochemical basis of living organisms below ground. It is primarily about soil structure, soil formation and clay minerals.
Chapter 2 describes the food basis for soil organisms. In a similar way as above ground, plants are providing most of the food below ground; they form the basis of most food chains in the soil. Soil organisms obtain plant nutrients either in the form of decomposing above ground material (leaf litter) or from plant roots.
Chapter 3 describes soil organisms living from the decomposition of dead organic material (either from plants or from other soil organisms).
Chapter 4 describes soil organisms living by preying on or parasitizing other soil organisms.
And chapter 5 describes soil organisms involved in mutualistic (mutually beneficial) interactions. This covers, amongst many other things, arbuscular mycorrhiza, one of my main research topics.
As already mentioned, the presentation is available for free and I don’t object against using it for educational purposes.