Soil organisms | And their Role in It

The soil is home to many organisms of the animal kingdom. These include

1. Bacteria
2. Protozoa
3. Fungi & Algae
4. Nematodes
5. Annelids (earthworms)
6. Molluscs
7. Insects and orthopods like ants, beetles
8. Amphibians
9. Reptiles like lizards and snakes.
10. Mammals like rodents

Organisms living in the soil in detail

Organisms live in the soil surface, sub-surfaces, and even in the depths of the earth at the highest temperature.

Bacteria

• These are organisms that are present everywhere, like in air, water, and land.

• However, the soil has more bacteria, and it is their natural habitat. As per an estimate, there is a ton of active bacteria in an acre of soil.

• Soil provides them with a required environment for growth, multiplication, and protection from the harsh climate.

• These bacteria, in turn, help the soil to be more porous, humid, and fertile. They act as decomposers and consume carbon compounds.

• They break down soil pollutants and pesticides. Further, they enhance soil water retention capacity and are also involved in disease suppression.

• Other animals and plants benefit from the presence of bacteria in the soil. One can find the bacteria even in the deepest layers of the earth.

Examples of soil bacteria include rhizobium, azotobacter.

Protozoa

• These are microbes that have cells similar to animal cells and are motile and lack a cell wall.

• Like bacteria, they are spread in the soil and mostly include ciliates and ameboids.

• Of the amoebas, naked ones dominate the soil. These protozoa feed on bacteria and fungi.

• They digest the bacteria and release more amount of nitrogen than the carbon consumed.

Fungi

• Fungi are multi-cellular animals that are found largely in soils.

• They are microscopic and grow as long threads called hyphae. 

• Like bacteria, they are also scavengers and help in the decomposition of waste.

They can be divided into three types

1. Decomposers
2. Mutualists
3. Pathogens or parasites.

• Except for the pathogens, the other two are beneficial for plants and animals.

• The fungi help in making soil humid, fertile, and suitable for the growth of plants.

• They can even kill nematodes and insects, which destroy plants and act as a biocontrol agent.

Algae

• These are similar to fungi but are autotrophic in nature.

• Algae are mostly found in water bodies like ponds and marines but also in the soil.

Nematodes

• These are parasitic animals that can be found in soil.

• They are long and slender and can live as parasites on other animals and plants.

• Nematodes are said to be the largest population of animals living in the world.

• They are of different types like bacteria feeders, fungal feeders, root feeders, etc.

This means they eat bacteria, fungi, and plant roots, respectively.

Annelids

• Earthworms are the best examples of this class living in the soil.

• They make burrows in the soil and live in it.

• These burrows help the penetration of water deep into the soil and also enhance soil fertility.

• Earthworms decompose dead and decaying matter and release tons of casts per acre every year. Thus, they help in the recycling of nutrients in the soil and are farmer’s friends.

Mollusks

• These are animals with smooth bodies having calcium shells over them.

• They are found in large numbers in calcium-rich soils.

Insects and orthopods

• A large number of insects, arthropods like spiders, centipedes, etc., live in the soil. Ants, beetles, and mites are also found in large numbers in the soil.

• They utilize soil to make burrows and hills to live in them.

• They act as fungal feeders, herbivores, and predators.

• They help to aerate the soil and also regulate the population of other soil organisms.

Amphibians

• As the name indicates, they can reside in the water and also on the land and in burrows.

• However, frogs and toads live in the soil for a considerable period. They even undergo a hibernation period in the soil layers for quite a long.

Reptiles

• Most reptiles tend to live on trees, but some of them also live in soil burrows.

• These include lizards and a few types of snakes.

Mammals

• Mammals, like rodents, live in soil holes that provide safety and dwellings.

• They search for food on the soil surface.

• But rest inside the burrows, give birth, and nourish their babies inside the soil.

Examples include rodents like rats.

References

• Soil organisms
• Role of Soil Bacteria
• Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria