How Soil Microbes Support Farm Ecosystems in Modern Agriculture

Evolution and natural selection are tools of change. Nature is relentless and patient, slowly encouraging slight modifications within a species that improve its chance of survival. Every living thing on earth today is the result of billions of years of design tweaks and process upgrades. 

Throughout evolutionary history, one thing has remained constant: the existence of microbes. 

Scientists have identified five kinds of microbes: bacteria, algae, fungi, protozoa and viruses. These microscopic wonders have existed for 3.5 billion years. Earth’s first residents were cyanobacteria, which slowly converted a poisonous atmosphere into the oxygen-rich air we breathe. Today, microbes are known as ecosystem recyclers, ensuring the stability of natural systems through trillions of microscopic changes to matter.

Anywhere a collection of cyclical processes depends on converting waste into usable form, microbes will be found, keeping things moving. They are located at the bottom of the deepest oceans, high up in the clouds, within live volcanoes, buried in the soil of farms everywhere, even on and inside all of us.

That’s why modern agriculture has enlisted them on our behalf. Microbes already use resources efficiently and build healthy soils, goals that are also pursued by farmers. Nearly 25 years ago, breeders figured out how to introduce Bt, a bacterium with natural insecticidal properties, into corn, soybeans, cotton, even eggplant. Today, they are pushing even further, looking for new ways to partner with billions of microscopic farm helpers.  

Playing in the Dirt

Beneath our feet is a hive of microbial activity, the presence of which is a key indicator of healthy soils. In fact, topsoil is the end result of microbes performing a variety of recycling tasks underground. After plants and animals die, their bodies decompose with help from bacteria and fungi. The outputs of this process become topsoil, minerals, and nutrients, all of which are made available to other animals and plants. It’s the circle of life, playing out on and underneath our soils. 
 

Another interesting microbial phenomenon occurs when bacteria and fungi form symbiotic relationships with plant roots to exchange nutrients and moisture, improving resilience in the face of pests and disease. 

Setting Nutrients Free

Nitrogen is necessary for all plants and animals, and it surrounds us, making up 80 percent of our atmosphere. The problem is plants and animals can’t use atmospheric nitrogen. 

But microbes can. An entire category of vegetables, known as legumes, has a symbiotic relationship with soil bacteria called rhizobia. Together, they can “fix” nitrogen into a usable form. Rhizobia are located within the root nodules of these plants, which include well known crops like soybeans, alfalfa, peas, and lentils.

Elsewhere in the soil, unattached microbes also take atmospheric nitrogen and nitrogen released from decomposing matter and convert it into usable forms for other species. 
 

Phosphorus, another key plant nutrient, is often bound up with other substances in the soil, rendering itself unusable. A category of soil bacteria and fungi, called phosphate-solubilizing microorganisms, can unlock it and make it available to plants. Microbes never stop recycling nutrients and matter.  

Various farming practices, including conservation tillage and the planting of cover crops, can encourage healthy microbial populations in soil. In each case, crop residue is left on top of the soil, attracting robust populations of microorganisms. They, in turn, convert that residue into nutrients and minerals. In addition to the nutrient benefits, soil microbes naturally capture and store carbon, preventing it from being released into the atmosphere. 

Innovation Inspiration

Microbes have been at work in our ecosystems for more than three billion years, setting an example farmers and researchers hope to follow. Agriculture has always been interested in reusing waste, maintaining our air and soil, and fostering plant relationships, all things microorganisms do well. This has led to a surge in research and development around microorganisms and their role in farming. 

Enter microbials, a category of products featuring live microbes. They can either be applied directly to seeds before planting, or sprayed on the plant once it has started growing. One category, known as biofertilizers, helps plants absorb vital nutrients like nitrogen and phosphorus. Biostimulants, on the other hand, bolster a young seedling’s defenses against pests, fungal diseases and weather events. These products package and deliver microbes where they can do the most good by functioning just as they do in nature. These are just two of the lessons researchers have learned from our microscopic friends. Imagine what else they will find. 

The Next Three Billion Years

Modern agriculture today is focused on innovation and efficiency. Microbes and the products they make possible, like microbial seed coatings, are at the forefront of these efforts. A critical mission is driving much of this work: sustainable food production for centuries to come. As we continue exploring the invisible world all around us, the possibilities for microbes appear endless. One thing’s for certain–the vast majority of microorganisms like bacteria, algae and fungi are natural allies on the farm. We don’t know what farming will look like far into the future, but it’s a safe bet that microbes will play an important role.