Beneficial Bacteria Species: What Are They and What Do They Do?

While plant growth and fertilizers are often intricately linked in modern farming, one cannot overlook the footprints such chemicals leave on our ecosystem. In the last few decades, we are realizing the importance of soil health. In the journey of shifting fortunes and eluding chemical toxicity, Nature indeed has the answers. And it is here that we find our answers for sustainable agriculture in beneficial soil bacteria. Let us take a look at what they are and what they do.

Beneficial Soil Bacteria: Key to Sustainability

Soil microbiome refers to the microorganisms naturally present in the soil, either in a close mutual relationship with higher plants or as free-living organisms within the soil. Most of these microbes are undoubtedly beneficial to the overall health of the plants and the soil as a medium for the sustainable growth of plants.

Soil microorganisms include various domains of microorganisms, not just bacteria. It comprises species of fungi, nematodes, protozoa, and archaea. Beneficial soil organisms are closely related to plant growth and natural nutrient cycles. Amidst the many groups, bacteria is prominently seen playing roles in plant growth promotion. Many bacterial species are present in the rhizosphere region (area near the plant roots) and work in a myriad of ways to boost fertility and soil health. One gram of rhizosphere soil can contain billions of microbial cells from hundreds of genera and species! 

However, the natural existence of soil bacteria gets altered due to continuous cultivation and usage variations. Regular use of agri-inputs like chemical fertilizers and pesticides, along with intensive farming processes often work to reduce the natural load of beneficial bacteria in the soil.

What is the Role of Bacteria in the Soil?

While the term bacteria often brings images of disease, most bacterial species are not pathogens. In fact, many of them are actually beneficial to us in many ways. Soil bacteria itself is a diverse group and embodies various types of bacterium species that vary in their role, structural habitat, and other environmental conditions. Beneficial soil bacteria are primarily of three types based on their activity. They are:

  • Mutualists
  • Decomposers
  • Lithotrophs
  • Mutualistic soil bacteria exist in a symbiotic relationship with plants exhibiting a mutual benefiting system. Decomposing bacteria work to recycle nutrients released into the soil and, most times, help boost soil fertility. Lithotrophs are a group of bacteria that utilize inorganic substrates and play a vital role in nutrient cycles like the nitrogen and sulfur cycle. 

    Soil bacteria have a wide array of roles to perform. Let us understand how these microorganisms support plant growth.

    • Symbiotic Relationships 

    Beneficial soil bacteria often live as symbionts - in a mutually benefiting existence - where they are present either internally or externally to the plants. The activity of these bacteria benefits the plant in a variety of ways. The bacteria, in turn, receive shelter and food (from the metabolic products of the plants). Rhizobium spp is a classic example of this type. They coexist with plants, forming a habitat within the root nodules of legumes like lentils, peas, beans, soybean, etc. Rhizobium takes part in the process of nitrogen fixation and converts atmospheric Nitrogen into plant absorbable forms like nitrates, thereby providing the plant host with a ready source of bioavailable nitrogen. 

    Another interesting symbiotic association is seen with most land plants and their fungal partners in what is known as “mycorrhiza.” The name mycorrhiza indicates a relationship between fungi and plant roots. These fungi form a close mutualistic symbiosis with the host plant roots and enhance the ability of the roots to absorb water and nutrients from the soil while thriving in the presence of root exudates. Mycorrhizal fungi may grow around the root hairs, or inside the root cells. Fungi of the genera Glomus, Pisolithus, Gigaspora, and Rhizopogon are among the important mycorrhizal partners. 

    • Decomposers Helping Improve Growth

    While decomposition is often considered a dead-matter breakdown process, such a process brings multiple benefits to soil health and flora existence. Actinomycetes sp, for instance, are the most typically occurring soil decomposers active even at higher soil pH levels. Such decomposers utilize simple organic compounds, decompose dead and decaying matter and release nutrients in a form that plants can uptake. Decomposers also prevent nutrient loss from plant roots. Decomposing soil bacteria form a cycle in the food chain, aiding the efficient flow of nutrients through the ecosystem

    As a bonus, soil decomposers also combat soil pollution, breaking down harmful chemical entities into non-toxic, simpler compounds and helping soil health, fertility, and making nutrients available.  

    • Free-living Non-Symbionts, Still Beneficial

    The last group of beneficial soil bacteria are non-symbionts, which exist as free-living organisms yet form a vital cog in the plant-nutrient cycles. They predominantly impact the movement of Nitrogen, Sulfur, and Phosphorus in the plant-soil environment. Bacterial species belonging to genera like Bacillus, Agrobacterium, Pseudomonas, etc., are important in converting insoluble Phosphorus into soluble forms and are vital to the healthy growth of plants, considering that Phosphorus is a significant plant macronutrient. 

    Some other soil bacteria like Pseudomonas sp drive the Sulfur cycle. They convert insoluble forms of sulfur in the soil into soluble forms and release them into the soil. These soluble forms are then available to the plants.  

    Leveraging Beneficial Soil Bacteria 

    Now that the many benefits of soil bacteria to plant growth and soil health are evident, getting the best out of them is a sensible choice in creating a sustainable ecosystem that supports healthy farming. As noted earlier, various environmental factors have altered the beneficial bacteria soil inoculant concentration through the years, many of them manmade. Thus, adding beneficial bacteria to soil externally can help soil bacteria levels surge, thereby promoting plant growth. 

    When chemical fertilizers are the only means of providing nutrients, through the seasons, many nutrients become unavailable because they react with the soil to form compounds that a plant cannot use. Soil bacteria can help make these nutrients available by producing acids and enzymes, that release the nutrients from the complex compounds that bind them. 

    Biofertilizers contain an optimal amount of carefully chosen species of beneficial microorganisms in the right ratio and are available in different forms commercially. When applied right, at regular intervals, they help to maintain a robust and diverse microbial community that supports soil health and plant growth. Consistent application of beneficial bacteria soil inoculant also proves to have upsides on soil health, which reflect in subsequent crop production.   

    Plant Revolution: Using the Power of Nature for Boosting Plant Growth  

    Plant Revolution’s expertly designed and developed products contain carefully chosen strains of beneficial soil microorganisms that support the growth of your plants. From mycorrhiza-based bioinoculants, to a meticulously developed mix of helpful bacteria to a natural nutrient mix to support the growth of beneficial soil microbes - Plant Revolution’s range of microbial inoculants is potent soil amendment products that support the growth of plants by enhancing the physical and chemical properties of the soil. The superior blends are designed for use by home gardeners, landscapers, farmers, and hydroponic growers.

    At the forefront of innovation, Plant Revolution is committed to continuing to work towards bridging the gap between research, knowledge, technology, and Nature. Buy our world-class products and ensure the strength of your soil and plants.