Soil bacteria: meaning and habitat, way of eating, benefits and harms

The role of soil bacteria cannot be overestimated. They are necessary to process organic residues into minerals, which is their main purpose. Consider the features of the habitat of microorganisms, their varieties and classification according to various criteria, how and what they eat. What is the difference between soil bacteria and decay bacteria.

General information

Soil bacteria and fungi contribute to the decomposition of organic residues to mineral elements, without this process the existence of biocenoses would be impossible. Their main significance is that they process particles of plant and animal tissues into nutrient humus, which is then used by new plants for nutrition, growth and development.The positive effect of bacteria is also noted in the fact that the humus resulting from their activity forms the soil, makes the top layer fertile, and improves the structure of the soil.

The benefits and harms of soil microorganisms are determined by their composition, varieties and quantity. Beneficial microorganisms do not always predominate in the soil, if for some reason harmful ones, such as mold, multiply, the substrate becomes unusable. The negative impact of mold is manifested in the oppression of plants, which leads to their death. Carriers of dangerous infectious diseases - tetanus, anthrax, intestinal infections and others can also be found in the soil.

Habitat

Different types of microorganisms in the earth feed on different organic residues, live in different layers. Mostly they are located in the area where the roots of plants are located. Microorganisms consume both fresh plant residues and substances that are located near the root system of plants.

For the successful growth of crops, it is necessary that photosynthetic bacteria live in the soil, first of all. Microorganisms of this type fix nitrogen from the air and carbon, produce organic matter and bind many other nutrients that feed plants and participate in the compound cycle.

Types of soil bacteria

The totality of the bacterial flora of the soil is divided into groups depending on the structure, oxygen consumption, functions, nutrition and other characteristics.

According to the shape of cell walls

The difference in the structure of the cell walls of soil microorganisms was revealed as a result of research. On this basis, unicellular are divided into 3 main groups:

bacilli, in which the cell has a cylindrical shape;
cocci with a spherical cell;
Spirilla having a spiral shape.

There are bacteria with a complex shape, such as actinomycetes, which have a branched shape.

In relation to oxygen

All soil bacteria are divided into groups, one of which consumes oxygen, the other can do without it. These are aerobic and anaerobic microorganisms. The attitude to oxygen also determines what reactions will take place with the help of these microorganisms. Anaerobic bacteria are responsible for fermentation processes, less energy is produced with this method than with the aerobic method, which is more efficient in this regard.

According to the ability to be stained by the Gram method

The method is based on the fact that some types of soil microorganisms have an outer protective shell that does not allow substances to enter. Such bacteria are considered Gram-positive, those that stain with dyes are Gram-negative.These include: Pseudomonas, Azotobacteria, unicellular rhizobia, Enterobacteria, cytophages, myxobacteria, nitrifying bacteria. Gram-positive microorganisms: bacilli, anaerobic, coryneform and spore-forming bacteria.

By food type

Microorganisms are divided into autotrophic and heterotrophic. Autotrophic in the process of life create organic compounds from inorganic, heterotrophic use organic matter for nutrition.

By function

Nitrifying species of microorganisms are used in order to increase the nutritional value of the soil. Nodule microorganisms fix nitrogen from the air and transfer it to the soil, nitrifying microorganisms convert nitrogen from ammonium to nitrate form, which increases its availability for plants.

By functional features, there are such groups of microorganisms:

Destructors that consume fresh organic matter, decompose and mineralize it.
Mutualists - able to exist with plants on mutually beneficial terms. An example is nodule bacteria.
Chemoautotrophs process carbon-free inorganic matter.
Pathogens causing plant and animal diseases.

All single-celled organisms, except pathogens, transform soil organic matter, accumulate nitrogen, neutralize toxic substances of pesticides, prevent plant diseases, form soil microaggregates that increase soil moisture capacity.

How bacteria eat

Soil bacteria use different methods to obtain nutrition and energy. Some feed on organic, others on inorganic substances. Decomposing organic matter, they build their own cells, inorganic substances are used for nutrition.

What is the difference between decay bacteria and soil bacteria?

Rotting processes are caused by saprophytes. They are located in the upper layer of the soil, their purpose is the decomposition of dead tissues at high speed. Saprophytes are demanding on organic matter, their vital activity is impossible without proteins, carbohydrates, nitrogen-containing substances, nucleotides, vitamins.

Soil microorganisms carry out functions in the earth related to the cycle of nutrients, water and inhibition of pathogenic bacteria. Some produce substances that bind soil particles into aggregates, which make it more structural, increase water-holding capacity. Many beneficial microorganisms compete with pathogens in above ground surfaces and root systems.