Soil flora

Soil flora and Soil fauna are terms used to describe the organisms that live within soils. The flora is composed primarily of microorganisms such as bacteria, actinomycetes, algae and fungi (though some fungi are visible to the unaided eye). The fauna is composed of microfauna such as protozoans, mesofauna such as nematodes and arthropods such as mites, centipedes, springtails, and macrofauna such as insects and worms, mice, moles et cetera.

The soil flora and fauna play important roles in agriculture and horticulture, performing such roles as decomposing organic materials, moving nutrients through soil layers, fixing atmospheric nitrogen, and improving soil structure.

Some parts of the soil flora and fauna are plant pathogens, while others are antagonists.

Soil ecology is very complex and not yet well understood. For example, while it is estimated there may be two million types of bacteria in the sea, there may be 4 million in one tonne of soil. Less than 1 per cent of these bacteria may be cultured in the lab, because suitable media cannot be found, i.e. the demands and roles of these organisms are not well understood.