Regenerative agriculture is the practice of farming in a way that rebuilds what has been lost in our soils. It focuses on promoting soil health and prioritizing biodiversity and ecosystem health. This is done through holistic practices such as crop rotation, livestock integration, reduced tillage, and cover cropping. One of, if not the most important aspects of soil health, is the health of the soil biology. The vast majority of which are microbes. These microbes are the unsung heroes of soil- and plant health. By understanding the pivotal role of soil microbes, we can better understand how we can promote soil health in our agro-ecosystems. Let’s take a look at how these microbes function to provide the food on our plates.
Understanding Soil Microbes
Soil microbes encompass a rich tapestry of microscopic life forms, including bacteria, fungi, archaea, protozoa, and nematodes. They all form part of the complex network of interactions known as the soil food web. These tiny organisms play various roles in soil health, ranging from nutrient cycling to organic matter decomposition and disease suppression. Their sheer diversity ensures the efficient functioning of ecosystems, developing resilience and adaptability, all while facing environmental challenges. For instance, bacteria are essential for nitrogen fixation (rhizobia) and nutrient mineralization and they facilitate the availability of essential nutrients to plants. On the other hand fungi form symbiotic relationships with plant roots (mycorrhizal fungi) aiding in the uptake of nutrients and enhancing plant resilience to stress. Nematodes and protozoa aerate the soil and improve its structure, while also regulating the populations of other microbes and cycling nutrients through predation.
The Role of Soil Microbes in Carbon Sequestration
Soil microbes have an integral role in carbon sequestration, the process by which atmospheric carbon dioxide is captured and stored in soil organic matter. Carbon is released into the soil through the decomposition of organic residues. Soil microbes break down complex molecules, and the simpler, carbon containing molecules are released. This carbon is then transformed into stable forms (i.e. humus) by certain microbes. These forms can persist in the soil for many years. This process, known as humification, effectively stores carbon in the soil, removing CO2 from the atmosphere.
Mitigating Greenhouse Gas Emissions
Soil microbes not only sequester carbon into the soil but they play a pivotal role in mitigating other greenhouse gas emissions. They affect the production and consumption of greenhouse gases like carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Certain microbes facilitate the conversion of soil organic matter into CO2 through respiration, while others consume methane (methanotrophic bacteria) and nitrous oxide (nitrous oxide reducing bacteria), effectively reducing their atmospheric concentration. Regenerative agricultural practices, promoting healthy soil microbial communities, can help mitigate greenhouse gas emissions by optimising microbial processes. By developing a balanced microbial ecosystem, farmers can reduce their losses in soil organic carbon and reduce their impact on the environment.
Strategies for Enhancing Soil Microbial Activity
Enhancing soil microbial activity is one of the main ways that you can achieve better soil health. Adopting these strategies listed below will support and nurture your soil’s microbes and maximize their activity in the soil:
- Reduced tillage: Minimising soil disturbance preserves the microbial habitats and promotes microbial diversity.
- Cover cropping: By planting cover crops in rotation with cash crops, you can increase the soil organic matter in your soil, while reaping the benefits of having living roots in the ground. Living roots feed the microbial communities in the soil.
- Organic amendments: The application of compost, manure, or other organic materials enriches the soil with nutrients and fosters a diverse soil microbiome.
- Microbial inoculants: Inoculating your soil with beneficial microorganisms, such as mycorrhizal fungi or nitrogen-fixing bacteria, can enhance the nutrient cycling and health of the plant.
This only scratches the surface on how important soil microbes actually are for the health of your soil, your crops, and the environment. For us to be able to farm in a way that maximises the health of these micro-workers it is important that we build a thorough understanding of their role in our soil and what we can do to create an environment where they can thrive.