Motivation for Soil Health
It’s easy to think of dirt as a lifeless pile of material. But, instead, it is a living system and is habitat for many different organisms that collectively contribute to different functions of the soil. We need it for sustenance. It even has its own lifecycle.
Think soil health is important? A bunch of soil scientists think so!
Let’s explore key players of the soil-food web, explore their vital functions, and discuss why nurturing this underground ecosystem is essential for sustainable agriculture and a healthy environment.
What Is the Soil-Food Web?
The soil-food web is composed of a myriad organisms that live all or part of their lives in the soil. It includes microscopic bacteria, fungi, protozoa, and nematodes, as well as larger invertebrates like earthworms, arthropods, and even burrowing mammals. These organisms form complex relationships—feeding on each other, decomposing organic matter, and forming symbiotic partnerships with plants. Together, they transform dead organic material into nutrients that plants can use, effectively acting as nature’s recycling system.
Understanding the soil-food web is key to grasping how energy and nutrients flow through ecosystems, and it reminds us that soil is not merely inert dirt, but a dynamic, living system.
The Key Players and Their Roles
Bacteria and Fungi
- Bacteria are the most numerous denizens of the soil, responsible for decomposing simple organic compounds and driving processes like nitrogen fixation and nitrification. These activities convert atmospheric nitrogen into forms that plants can absorb and use to build proteins.
- Fungi, particularly saprotrophic fungi, break down tougher organic materials such as cellulose and lignin. In addition, mycorrhizal fungi form symbiotic relationships with plant roots, extending their reach for water and nutrients while receiving carbohydrates in return. This partnership is vital for plant health and productivity.
Together, these microbes are at the forefront of carbon and nitrogen cycling, the foundation of soil fertility.
Microfauna to Macrofauna
- Protozoa and Nematodes help regulate microbial populations by feeding on bacteria and fungi, stimulating further nutrient release.
- Earthworms and Other Macrofauna act as natural tillers by burrowing through the soil, which enhances aeration and water infiltration. Their digestive processes break down organic matter and mix it into the soil, further boosting nutrient availability.
Each group, regardless of its size, contributes to the stability and productivity of the soil-food web.
Why the Soil-Food Web Matters
Nutrient Cycling and Plant Health
The soil-food web is an interconnected community of organisms in the soil that work together to drive nutrient cycling, support plant growth, and maintain ecosystem health.
Some elements such as nitrogen (N), phosphorus (P), potassium (K) and zinc (Zn) enhance soil health while others such as cadmium (Cd) and arsenic (As) that are harmful to human health (Brevik and Burgess, 2013). These nutrients can be added through fertilizer, but don’t forget the thing you do to your plants more frequently: Water!
- Balance among these minerals is key. An overdose of N depletes the soil. The below chart illustrates the balance of N and P in different areas of the world.
- Mineral quality matters. While N is naturally-occurring in soil many commercial fertilizers use synthetic, manufactured N. The latter is known to degrade soil quicker.
- Water quality matters. Make sure that your water supply retains essential minerals like potassium and magnesium. Many municipal water supplies and water filters strip the naturally-occurring minerals then add them back in. Water filters and ionizers like this one keep the minerals and balance the pH to be friendly to your plants and soil.
The soil-food web is central to nutrient cycling—the process by which organic matter is decomposed and recycled into essential nutrients for plant growth. Without the diverse organisms in the soil, dead plant material would accumulate, and nutrients would remain locked in forms unavailable to plants. By breaking down organic matter, the soil biota releases nutrients like N, P, and K, ensuring that plants have continuous access to the resources they need.
Regenerative agriculture highlights that a reduction or cessation of synthetic inputs is needed to allow natural process to return to soil. A shift towards regenerative agriculture often includes a goal to reduce the usage of synthetic inputs, minimizing tilling, and other practices.
Carbon Sequestration and Climate Regulation
Healthy soils rich in organic matter serve as significant carbon sinks, helping to mitigate climate change by storing carbon that would otherwise contribute to atmospheric CO₂ levels. The microbial processes in the soil not only release carbon through respiration but also contribute to the formation of stable compounds such as humus, which can persist in the soil for decades or even centuries.
Soil Structure and Water Management
The activities of soil organisms enhance soil structure by creating aggregates and pore spaces that improve water infiltration and retention. Better soil structure means reduced erosion, improved drainage, and increased resilience during droughts—benefits that are critical for both natural ecosystems and agricultural systems.
Supporting a Thriving Soil-Food Web
Given its importance, how can we foster a vibrant soil-food web? Here are some practical steps:
- Organic Amendments & Composting: Add organic matter through compost and green manures feeds soil microbes and improves soil structure.
- Reduced Tillage: Minimize disturbance preserves the networks of roots and soil organisms.
- Cover Cropping: Plant cover crops to help maintain organic matter, suppress weeds, and provide habitat for beneficial soil organisms.
- Integrated Pest Management: Encourage natural predators and avoiding excessive chemical inputs helps maintain microbial balance and ecosystem resilience.
Farmers, gardeners, and land managers are adopting these practices to enhance soil health, boost crop productivity, and contribute to climate change mitigation. Many people, like Ric Scalzo of Institute for Botanical Research at Sonoran University and founder of both Gaia Herbs and Kokoroa Life, purchase farms and spend a lot of time and money to convert it to healthy soil practices via regenerative agriculture. In the conference I recently attended, he said the curcuminoid percentage of turmeric grown on his land is 8.5% versus the 2.5% yield of that grown in Asia.
Final Thoughts
The soil-food web is how the dynamic life of soil impacts our food supply. From the microscopic bacteria and fungi that break down organic matter to the larger creatures that aerate and mix the soil, every organism plays a part in an ecological network. Global challenges like food insecurity and climate change impact our farmers’ choices, but we can control our home-grown crops and encourage local growers to adopt soil-healthy practices.
In the words of soil biology pioneer Dr. Elaine Ingham, who has dedicated her career to unlocking the secrets of the soil-food web, “Healthy soil is the foundation of a healthy planet.”
Let’s work together to protect and regenerate the soil—a living resource that supports all life on Earth.
References:
- Soil Food Web. Wikipedia, The Free Encyclopedia. Retrieved February 24, 2025, from https://en.wikipedia.org/wiki/Soil_food_web
- Soil Biology. Wikipedia, The Free Encyclopedia. Retrieved February 24, 2025, from https://en.wikipedia.org/wiki/Soil_biology
- Elaine Ingham. Wikipedia, The Free Encyclopedia. Retrieved February 24, 2025, from https://en.wikipedia.org/wiki/Elaine_Ingham
- Colley et al., 2019; Rhodes, 2017
- Ryan and Singh. “Managing Fertilizers to Enhance Soil Health”. May 2015. First Edition, IFA, Paris, France.
- Founding an Herbal Product Business Today with Ric Scalzo. Ric Scalzo. 2025 Virtual Herbalism Conference. The Herbal Academy.
- Pimentel and Wilson, 2004
- Brevik 2013
- The food balance sheets prepared by the United Nations Food and Agricultural Organization (FAO)
