The invisible world of beneficial microbes—fungi and bacteria that aid human, plant, and ecosystem health—is now a hot topic. There are bestselling books about the fungal networks of forests, growing awareness about the influence and importance of the microbiome in all aspects of human health, and hit documentaries exploring how soil microbes are critical to saving the planet from climate change, pollution, drought, and more.
As often happens when research becomes mainstream news, it can be difficult to distinguish where the science ends and the compelling story continues. So, it is an important question to ask: can soil microbes really “save the planet”?
We may be only beginning to understand the full significance of soil microbial communities, but we do know that they have a vital role to play in any sustainable agricultural system of the future. Although it is unlikely that microbes alone will solve our greatest environmental challenges, here is a realistic look at how they can help make it possible.
Why Soil Microbes Matter
Life on Earth began with microbes, and they remain the foundation of all of the planet’s living systems. Diverse communities of bacteria and fungi create microbiomes—complex ecosystems within ecosystems.
A healthy, diverse microbiome is both an indication and a requirement of a healthy, diverse ecosystem. If soil microbial diversity declines, so too does ecosystem stability and human food security. Without a solid microbial foundation, the earth systems that sustain us begin to crumble.
Simply put, without microbes, we are nothing. And, with the looming threats of climate change, water scarcity, land degradation, and a growing human population, healthy microbiomes are more important than ever. A healthy soil microbiome will recycle and transform essential plant nutrients, break down pesticides and other pollutants, improve drought resilience, and keep pests and pathogens in check.
Unfortunately, the beneficial microbes in our soil are threatened by modern agricultural practices like heavy pesticide use, tilling, and monocropping. Microbes need our help if they are to help us, and rethinking how we grow food is a critical part of this puzzle.
Beneficial Microbes and Sustainable Agriculture
More than 40% of the planet’s land is already used for agriculture, a figure that continues to increase. How we grow our food truly does define the future of life on our planet.
Many conventional agricultural practices have far-reaching environmental consequences. Tilling releases soil carbon into the atmosphere. Chemical pesticides pollute waterways and contribute to the grave threat of antimicrobial resistance (AMR). Synthetic nitrogen fertilizer releases extremely potent greenhouse gasses. Monocultural growing systems increase plant vulnerability to biotic and abiotic stresses, like pathogens and drought.
These practices all impact soil microbial diversity as well. And as the soil microbiome deteriorates, their negative effects are exacerbated further. Plants develop slower and become less resilient. More fertilizer, more pesticides, and more land are needed just to maintain yields.
It makes intuitive sense that microbial health scales up to reflect planetary health, and science increasingly supports that. We need healthy soil microbes to secure a healthy planet. There are a few key steps to make that happen.
Fixing the Fertilizer Problem
Synthetic nitrogen fertilizer is energy-intensive to produce and its overapplication pollutes groundwater, rivers, and oceans. Runoff fertilizer causes eutrophication—toxic algae blooms that devastate aquatic ecosystems. It is estimated that half of all nitrogen is ultimately lost through ground and surface water or into the atmosphere in the form of nitrous oxide (N2O).
Over a 100-year timeframe, N2O is 273 times more potent than carbon dioxide (CO2) as a greenhouse gas. Reducing fertilizer emissions is one of agriculture’s most pressing challenges, and microbes feature into the solution in two different ways.
First, most of the N2O emissions from agriculture are generated through microbial nitrification, or the oxidation of ammonia to nitrates like N2O. But changes to the soil ecology can reduce these emissions. For example, biochar—a carbon-rich biostimulant produced by heating biomass at high temperatures and in low oxygen environments—can encourage a diversity of N2O-reducing microorganisms. Studies of biochar applications have reported a reduction of N2O emissions by 50–80%.
Beyond potentially mitigating N2O emissions resulting from nitrification, microbes can also reduce the need for synthetic fertilizers in the first place. Beneficial microbes improve the bioavailability of nitrogen and other essential nutrients in the soil. Certain bacteria can also “fix” more nitrogen in the soil by converting atmospheric nitrogen (N2) into plant-available ammonia (NH3).
Utilizing biological fertilizers and microbial inoculants to introduce and encourage the growth of these microbes is among the most promising strategies to significantly reduce fertilizer demand in both conventional and organic systems.
Reducing Pesticide Use
Agricultural pesticides are widely recognized for contributing to the dramatic worldwide declines in biodiversity documented over the past 50 years. Most pesticides also degrade the soil microbiome, eliminating the very system protecting plants not just from pests and pathogens but from the increasing abiotic threats of drought and extreme heat as well.
Microbes can also be used as pesticides themselves in place of destructive chemical products. Microbial pesticides containing bacteria, fungi, viruses, protozoans, algae, and mycoplasma can provide non-toxic pest control through different mechanisms, from introducing pheromones that interfere with insect mating to inducing a plant’s own resistance response.
Keeping Carbon in the Ground
Beneficial microbes can not only improve the sustainability of our agricultural systems, but they can also potentially help in reversing, or at least slowing down, the accumulation of CO2 in the atmosphere.
Soil microbes influence how much carbon is stored in the soil as well as how much is released back into the atmosphere. They also indirectly influence carbon storage in plants and soils by supplying macronutrients that regulate productivity, like nitrogen and phosphorus.
Minimizing tillage and using cover crops keep this carbon in the ground. We still don’t understand exactly how and to what extent microbes similarly contribute to long-term carbon sequestration in soil, but researchers are beginning to explore the possibility of a soil microbial carbon pump (MCP). The MCP concept hypothesizes that microbial growth and death may help transform and store significant amounts of carbon.
Harnessing Soil Microbes to Save the Planet
“When we try to pick out anything by itself, we find it hitched to everything else in the Universe,” the naturalist John Muir famously said. The more we learn about microbial life, the more this insight holds true, and we are still only beginning to understand how microbiomes intricately tie entire living systems together. While soil microbes alone may not provide planet-saving solutions, no solution will succeed without considering them.
Through our agricultural systems, we can harness the environmental benefits of microbes and encourage soil microbial diversity in a few essential ways:
- Incorporating no or low-till and cover cropping to preserve soil structure and microbial diversity
- Exploring novel plant biostimulants to support plant growth-promoting rhizobacteria and reduce N2O emissions and reliance on chemical fertilizers
- Reducing chemical pesticide use in favor of microbial pesticides to conserve soil health, ecosystem biodiversity, and long term crop resilience
- Applying high-quality, research-backed microbial inoculants to improve plant productivity and stress resilience.
Microbial health, human health, planetary health—it’s all hitched together. If nature is to continue working for us, we need to work for nature. As growers, we can do that by changing certain farming practices and expanding our understanding of microbial life. We can work with microbes to prioritize soil health, reduce reliance on chemical inputs, improve plant resiliency, and create more planet-friendly fertilization programs.
Ready to get started? We’re here to help. Our mission at Impello is to create solutions that benefit both growers and the planet. Check our line of microbial inoculants and biological fertilizers here or get in touch at firstname.lastname@example.org to learn more!
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