A microorganism is a term given to small living beings whose size is
measured in microns. Bacteria, fungi, algae, and protozoans are a few of them that
reside in the air, water, and soil. This review is about the microorganisms found in soil.
These microorganisms have different functions in soil decomposition of dead organic
matter, such as ecological food web balance, and making nutrients available to plants.
Recently, their role in alleviating different abiotic stresses like salinity and drought has
been marvelous. These microbes are also being used in biopesticide form, which is
environmentally friendly and safe for other living organisms. Bacteria convert the
inaccessible nutrients from dead matter into usable forms. Actinomycetes give off the
typical smell of soil, and these microorganisms are also being used as a source of
therapeutic medicines. Fungi are helpful in the way that they break down impossible
nutrients, which are then available to other microbes. They also colonize plant roots
and thus aid in plant growth. Algae promote submerged aeration as their photosynthesis
is faster and adds more oxygen. Algae also help prevent the loss of nitrates that help in
building soil structures by promoting the weathering of rocks. Nematodes help
maintain the ecological equilibrium of their habitat. Viruses are the mode of gene
transfer between organisms in the soil. Thus, these microorganisms have different
functions in the soil to maintain the soil's structure and the balance between the
environment and its living beings.