Even within each group, there is great diversity in form and function. The rhizosphere is the interface between plant roots and the soil environment. It is the location of much soil biological activity and plant-microbe interactions including symbioses, pathogenic infection, and competition. E. Soil organisms are part of a living system. Ecosystem characteristics largely determine the structure of soil communities.
Weather determines daily and seasonal variations in biological activity.
The types of species present and their level of activity depends on micro-environmental conditions including temperature, moisture, aeration, pH, pore size, and types of food sources. Arid systems have few earthworms, but have termites, ants and other invertebrates that serve similar functions. Grasslands have near equal amounts of fungal and bacterial biomass, or may be dominated by bacteria. Coniferous forests may have 100 to 1000 times more fungal biomass than bacterial biomass. We need soil organisms for the services they provide.