The soil teems with life. This represents a large portion of the soil organic matter pool in some soils. We tend to be more familiar with the macroscopic or larger scale soil animals because this is what we see in the soil during tillage or when we look at the crop root systems. At the microscopic level we have fungi, bacteria, actinomycetes and algae in most soils. The population vary though depending upon soil type, pH, soil cover or crop rotation and tillage.
Fungi make up the largest amount of living material after plant roots.
They are intolerant of intensive tillage. Fungi help to make soil nutrients available to plants and are greatly involved in decomposition of organic matter. Research has shown that this fungi can enhance the uptake of phosphorous in low phosphorous soils. Bacteria number in the billions in most soils. They are important for maintaining good soil quality and fertility.