Soil Microorganisms: How Hidden Root Partnerships Drive Healthy Crops and Soil Fertility

The healthy crop will host a very intense "communication" of chemical signals with the biological network living underneath it. This invisible communication system is integral that influences the health and nutrient absorption capabilities of plants and the productivity of soils for generations to come. This symbiosis between plant roots and soil microbes relationship that enables the crop to more efficiently take up nutrients from the soil and tolerate environmental stresses.

The continuing research in modern agriculture has continued to show the significance of plant soil microbe interaction in sustainable agriculture.As continuous research in agriculture has confirmed, one of the cornerstones of sustainable agriculture is the relation of plant-soil-miche. The specific beneficial soil microbes that surround the root zone of the plants such as beneficial bacteria and fungi help them to absorb nutrients, build their own defenses and promote proper plant growth throughout the growing season. These soil micro-organisms are optimised at the root of the plant life (rhizosphere). The sub-soil interaction can be understood so that farmers can use farming techniques to make it more productive without compromising soil health for future generations.

What is the rhizosphere and why is it referred to as “the plant's communication hub?”

The rhizosphere, a small zone of soil around the root system where there is continual biological and chemical activity. The area is a very dynamic part of the soils of agriculture in containing the largest number of soil microorganisms.

Sugars, amino acids, organic acids and signaling molecules are naturally excreted by plant roots into the rhizosphere. These compounds are used to feed beneficial soil organisms and to act as a cue for beneficial soil microbes. In turn these microorganisms colonize the root surface and root zone soil of selected plants making a mutually beneficial relationship with the plants to help plant nutrition and health.

The rhizosphere contains a diverse microbial population which helps to improve the soil structure, nutrient availability and disease control. This diversity is important because the beneficial relationship that is established between plants and microbes is dependent on the presence of a good balance of the plant soil microbe interaction; this favours its effectiveness throughout the growth stages and ability to satisfy the need of the plants.

How plant roots recruit beneficial soil microbes?

Plants also interact with the microbes around them to a certain extent, as opposed to relying on the naturally occurring soil microorganisms. Roots of plants secret chemical compounds that attract beneficial soil microbes that promote plant growth, but not all soil microbes benefit the plants.

These microbes colonize the roots or soil around the roots when they are recruited and become durable biological communities that are mutually advantageous to both the plant and the microbes. This continuous plant soil microbe interaction helps the plants take up the nutrients more effectively, supports root growth and boosts the plant's resistance to environmental stress.

There are various groups of microbes in the rhizosphere working in complementary ways. Some bacteria can recycle nutrients that plants can't or make them more accessible to plants, some fungi grow and expand plant's root zones into areas that roots couldn't reach. These relationships combine to improve the health of crops and more productive farms.

Symbiosis of the plants' roots and soil microbes

A symbiosis between plant roots and soil microbes is one of the most effective natural biological collaborations. The plants also deliver materials for energy, resulting from photosynthesis, and the microorganisms deliver various services, including nutrient mobilization, biological protection and soil fertility enhancement.

Scientific studies have taken many forms to investigate the benefits of using multiple soil microbes for crops, and all have shown greater tolerance of environmental stresses, disease resistance, and nutrient use efficiency, amongst other beneficial soil microbes. Use of beneficial fungi, nitrogen fixing bacteria and phosphorus solubilising organisms all helps to sustain productive agricultural soils.

The value of retaining productive soil microorganisms is being recognized as crucial goals in the ongoing farms and markets research effort for regen agriculture and integrated crop management and the following collaborations show how this is important.

Nature's most important pairing of root and microbe: N Fixation

One of the most beneficial biological processes in the vicinity of plant roots, from the aspects of nitrogen fixation is the nitrifying bacteria. Crops can't absorb atmospheric nitrogen but nitrogen makes up most of the earth's atmosphere.

The special types of beneficial soil microbes or soil microorganisms, such as Rhizobium, Azotobacter, Azospirillum and Frankia which convert the atmospheric nitrogen into ammonia and other substances available to plants. Nitrogen Fixation is a natural process whereby nitrogen (N) is transformed into a plant essential for the crop growth, synthesis of chlorophyll, protein and for healthy vegetative growth of the crop.

This encourages more nitrogen-fixing microbes in the soil leading to increased nutrient cycling, reduced need for synthetic nitrogen fertilizers, better soils long-term in cereals, legumes and vegetables, as well as many other crops.

P1. Phosphorus Solubilization: Making nutrients available in the soil that is not available

Agricultural soils may be oversupplied with phosphorus but have it tied up in a form unavailable for uptake by crops. If the plants aren't helped in any way, they can only get a portion of this vital nutrient.

Others decompose soils, including the production of organic acids and enzymes to promote soil phosphorus solubility, thus making it more readily root taken up. This bio-process helps to improve nutrient cycling, early cropping and root growth.

The rhizosphere has an active beneficial soil microbes population that is assisting soil microorganisms to continually enhance the availability of phosphorus, resulting in improved flowering rates, grain development and overall crop productivity.

The decomposition of soil microorganisms breaks down and removes organic material back into the living cycle, how?

Biological nutrient cycling (mostly through microbial organisms in soil) is an important Soil quality trait for productive soils in the field. When nutrients are readily absorbed by the plants, organic matter is decomposed into nutrients by the bacteria, fungi, and/or other very small living things that decompose the organic matter that is consumed by them.

Microbial mineralization of crop residues and organic amendments releases nutrients (N, P, S etc,), and can help to enhance soil physical and organic carbon properties. The cycle doesn't stop there and there is no reliance on too synthetic a set of inputs in order to maintain fertility.

A living (biologically active) rhizosphere promotes a less nutrient deficient plant soil microbe interaction in the growing season and higher production of the crop. In the long-term, it is becoming more important to ensure different populations of beneficial soil microbes are maintained to maintain productive agricultural soils.

Beneficial soil Microbes in stress tolerance of plants to the environment

Lack of water, salinity, lack of nutrients, temperature variation etc., are stresses that crops experience as a result of environmental challenges. Plant resilience to many of these stress factors is achieved by the activities of plant soil microbe interaction that benefit the root system and plant's physiological capabilities.

The microorganisms improve the rate of water absorbed by the plant, increase root branching and uptake of nutrients even in bad growing conditions, by the close association to the plant roots. An undisturbed rhizosphere also contains microbes that trigger plant defence mechanisms that help them survive better to cope with environment stresses.

Healthy Soils Microbiota (MSM) in Climate Smart Farming is emphasized, and a study is in progress to uncover how the healthy relationship between soil microorganisms and plants is a key to the proven resilience in crop production.

How Novobac METILO fosters the communication between the roots and micro-organisms

Novobac's biological crop solutions foster the plant's performance through supporting its natural soil biology. Novobac METILO Microbial Biostimulators for Plants are built to promote the interaction between the root system and soil microorganisms, resulting in better health for both the “roots,” and community of soil microorganisms.

METILO promotes positive microbial movement in the rhizosphere which allows for greater vigor in plant soil microbe interaction, enhanced root development and increased plant vitality. METILO enhances sustainable crop production programs in Canada, the United States, Mexico, Europe, India and Southeast Asia by creating a friendly environment for the beneficial microbial communications and biological activity around the plant roots.
The product will easily fit into any modern regeneration program where fostering some sort of beneficial soil microbes is a key catalyst for long term productivity and soil health.

Support provided to phosphorus solubilisation naturally by Novobac Cropium

Another notable biological solution is Novobac Cropium, which contains Penicillium bilaiae, a good fungus noted for its natural ability to have a better effect on phosphorus solubilising.

Cropium enhances the availability of phosphorus and other plant nutrients through deeper rhizosphere activity, whereby soil microorganisms release more nutrients in the vicinity of the roots that are unavailable to the plant. Better uptake of phosphorus leads to better root growth, higher use efficiency of nutrients and better nutrient cycling during the growing season.

Novobac Cropium can be used in all sustainable farming systems, thus contributing to the improvement of the farmers' biological nutrient management and less dependence on the use of conventional phosphorus solubilization.

Developing a more aggressive plant rhizosphere protected, durable ground cover system suitable for sustainable agriculture

It takes a long-term strategy and management practices to create a healthy rhizosphere, so as to avoid the disruption of soil biology. Actions such as reducing unnecessary tillage, building soil organic matter, maintaining diversity in the cropped area, and reducing unnecessary application of chemicals all help to support healthy populations of soil microorganisms.

Subsequently, the inclusion of microbial biostimulants, good fungi and other biomass products enhances plant-soil-microrganism interaction and it is beneficial for enhancing nutrient cycling and plant resistance to various stressful conditions. A range of products like Novobac METILO and Novobac Cropium support such practices by stimulating the soil-biological processes that make nutrients available and stimulate root growth.

With your agriculture transition spreading toward regenerative production systems, knowledge and knowing how to connect and support the invisible dialogue between plant roots and microorganisms will continue to be vital to enhancing soil health, maintaining crop yields and strengthening agriculture going forward.

Reference:  

• Ramos Cabrera, Efrén Venancio, Zuly Yuliana Delgado Espinosa, and Andrés Felipe Solis Pino. "Use of phosphorus-solubilizing microorganisms as a biotechnological alternative: a review." Microorganisms 12.8 (2024): 1591.
• Balestrini, Raffaella, et al. "The hidden side of interaction: microbes and roots get together to improve plant resilience." Journal of Plant Interactions 19.1 (2024): 2323991.