Beneath every productive farm, an invisible workforce clocks in day and night without rest, without wages, and without complaint. They ask only one thing: that we stop poisoning them. These workers are the microbes and earthworms of the soil, and understanding what they do — and why they matter so profoundly — is central to the practice and philosophy of natural farming.
Bacteria: The Nutrient Cyclers
Bacteria are the most numerous organisms in soil. A single gram of healthy agricultural soil can contain anywhere from 100 million to 1 billion bacterial cells representing thousands of species, each with a specific role in the soil ecosystem.
Among the most important are nitrogen-fixing bacteria. Plants require nitrogen to build proteins and grow, yet despite living in an atmosphere that is 78% nitrogen, they cannot absorb it directly from the air. Bacteria like Rhizobium (which forms nodules on the roots of legumes), Azotobacter, and Azospirillum perform the remarkable task of converting atmospheric nitrogen into ammonium — a form plants can actually use. This biological nitrogen fixation is the basis of fertility in natural farming systems, replacing the need for synthetic urea entirely.
Other bacteria are decomposers, breaking down organic matter into simpler compounds that other organisms can use. Actinomycetes — a group of bacteria that appear as white, thread-like masses in compost — are responsible for breaking down tough materials like lignin and cellulose. They also produce antibiotics that suppress soil-borne diseases, and their activity is what gives healthy soil that characteristic pleasant, earthy smell.
Phosphate-solubilising bacteria are another crucial group. Phosphorus exists in abundance in most soils, but largely in forms that plants cannot absorb. These bacteria release organic acids that dissolve bound phosphorus and make it available to plant roots — a function that synthetic phosphate fertilisers attempt to replicate but achieve far less efficiently.
Fungi: The Underground Internet
If bacteria are the workers of the soil, fungi are its communications and logistics network. Fungal hyphae — the long, thread-like structures that make up the fungal body — can extend for hundreds of metres per gram of soil, weaving through every pore and around every particle.
Mycorrhizal fungi represent one of the oldest and most successful partnerships in the natural world — a relationship that has existed for at least 400 million years, predating even the evolution of modern plant root systems. These fungi colonise plant roots and extend their hyphae deep into surrounding soil, dramatically expanding the root’s effective surface area. In return for sugars that the plant provides, mycorrhizal fungi supply phosphorus, zinc, copper, and water from zones the roots alone could never reach.
Research consistently shows that mycorrhizally colonised plants are more drought-tolerant, more resistant to root diseases, and more nutritious. In natural farming systems across Andhra Pradesh and Telangana, where ZBNF has been practised at scale, farmers consistently report that crops show better tillering, stronger root systems, and improved resilience in dry spells — all characteristics associated with robust mycorrhizal networks.
Saprophytic fungi, including species familiar to us as mushrooms, decompose dead organic matter. They are particularly effective at breaking down woody materials, converting crop residues into humus — the dark, stable organic matter that gives fertile soil its richness.
A crucial point: synthetic fungicides, routinely applied in conventional farming to control foliar and soil-borne fungal diseases, are devastating to mycorrhizal populations. Once mycorrhizal networks are destroyed, plants become entirely dependent on external nutrient inputs — which is precisely the dependency that chemical agriculture creates and then profits from.
Earthworms: The Soil Engineers
Charles Darwin spent 40 years studying earthworms and concluded that no other creature had played as important a role in the history of the world as these humble animals. That assessment has only grown stronger with modern soil science.
Earthworms do several things that no other organism does as efficiently:
Physical mixing: Earthworms ingest soil and organic matter, passing them through their digestive system and depositing the mixture as castings. In doing so, they physically blend organic matter into the mineral soil, achieving an integration that even the most careful tillage cannot replicate. A single hectare of healthy soil can contain 400 to 1,200 earthworms, processing tonnes of soil annually.
Improved soil structure: Earthworm burrows create a network of channels that allow air and water to penetrate deeply into the soil profile. These burrows also provide pathways for plant roots to follow. Studies show that soils with active earthworm populations have significantly better water infiltration rates — meaning more rain soaks in rather than running off.
Nutrient concentration: Earthworm castings are extraordinary. They contain five times more nitrogen, seven times more phosphorus, eleven times more potassium, and three times more magnesium than the surrounding soil. They also contain beneficial microbes and plant growth hormones. Earthworm castings are among the most complete natural fertilisers available.
Soil pH balancing: The mucus that earthworms secrete as they move helps buffer soil pH, contributing to the neutral to slightly acidic conditions that most crops prefer.
How to Encourage Earthworm Populations
Earthworms thrive where organic matter is abundant, soil moisture is consistent, and chemical inputs are absent. Practical steps to encourage them include:
- Mulching: A layer of straw, dry leaves, or crop residue on the soil surface provides food, maintains moisture, and keeps soil temperatures moderate.
- Avoiding tillage: Deep ploughing destroys earthworm burrows, kills worms directly, and exposes their eggs to predation and desiccation.
- Applying Jeevamrutha: This fermented preparation provides a food source and microbial diversity that earthworms thrive on. Farmers who have applied Jeevamrutha for two to three seasons consistently report dramatic increases in earthworm populations.
- Composting: Adding compost introduces earthworm eggs and provides rich organic matter.
- Stopping chemical inputs: Pesticides and synthetic fertilisers are directly toxic to earthworms. The transition away from chemicals, even partial, yields immediate improvements in earthworm numbers.
In the Himalayan foothills of Uttarakhand, natural farmers who have practised these methods for five or more years report finding three to four times more earthworms per square metre than their neighbours using conventional practices.
The Connection Between Soil Life and Crop Health
The relationship between a thriving soil biology and crop health is not incidental — it is causal. Plants in biologically rich soils are better nourished, less stressed, and more naturally resistant to pests and diseases. They do not need to be propped up by external chemical inputs because the ecosystem beneath them is functioning as it evolved to function.
This is the core insight of natural farming: a healthy crop is the result of a healthy soil, and a healthy soil is the result of a healthy soil community. Everything begins underground.
Next week, we move from understanding soil life to actively building it — exploring the practices that restore soil fertility, from cover crops and mulching to biochar and soil observation methods that any farmer can use.