How Carbon, Nitrogen, Minerals, Water and Life Move Through One Continuous System

A fallen leaf is not rubbish.

A dead root is not useless.

Animal manure is not merely waste.

Even the body of a dead microbe does not simply disappear.

In a functioning ecosystem, materials are continually captured, transformed, exchanged, stored and released again. What appears to be an ending for one organism becomes a beginning for another.

Nature does not operate through disposal.

It operates through cycles.

Carbon moves from the atmosphere into plants, roots, microbes and soil. Nitrogen passes between the air, microorganisms, organic matter and plant tissue. Minerals weather from rock, enter living organisms and eventually return to the ground. Water carries dissolved compounds, supports reactions and connects nearly every part of the system.

Nothing remains in one form forever.

At The Redox Garden, this changes how we see nearly everything. A plant is not merely a crop. Mulch is not merely ground cover. Compost is not merely decomposed material. They are all parts of a living network through which matter and energy continue moving.

A cycle is not a circle

It is tempting to imagine nutrient cycles as neat diagrams:

Atmosphere → plant → animal → soil → atmosphere.

Real ecosystems are much more complex.

Carbon may be captured by a leaf, moved into a sugar, released through a root, consumed by a bacterium, incorporated into fungal tissue, eaten by a protozoan, released as a plant-available nutrient, attached to a mineral surface and stored in a soil aggregate.

Some of it may return to the atmosphere within hours.

Some may remain in the soil for years or longer.

Nitrogen may be fixed by bacteria, absorbed by a plant, built into protein, eaten by an insect, returned in manure, immobilised by microbes, mineralised into ammonium, transformed into nitrate or lost to water and air.

These are not simple loops.

They are branching pathways, temporary stores, exchanges and transformations.

A healthy ecosystem does not prevent movement. It keeps valuable materials moving through biological pathways instead of allowing them to escape unnecessarily.

Carbon: the currency of the living system

Carbon is the structural backbone of sugars, fats, proteins, DNA and most of the molecules from which living organisms are built.

But carbon is more than physical material.

In the form of sugars and other organic compounds, it also carries captured energy.

Plants bring carbon into the living system through photosynthesis. They take carbon dioxide from the atmosphere and, using energy from sunlight, combine it with water to produce energy-rich organic compounds.

That carbon can then move in several directions:

• into leaves, stems, flowers, fruits and seeds;
• down into roots;
• out of living roots as exudates;
• into microbes and animals that consume plant material;
• into litter, dead roots and woody matter;
• into soil organic matter;
• or back into the atmosphere through respiration and decomposition.

Carbon is continually moving between air, life and soil.

The carbon tunnel beneath every living plant

You mentioned carbon tunnelling, and that is a powerful way of picturing what living roots do, although it is not a standard technical term in soil science.

A plant acts almost like a biological tunnel carrying carbon from the atmosphere into the ground:

Atmosphere → leaf → sugar → stem → root → rhizosphere

The leaf captures atmospheric carbon.

The plant converts it into sugars.

Those sugars are transported through the plant.

A portion is delivered below ground, where it becomes root tissue, mucilage, sloughed cells or root exudates.

This process is more formally called rhizodeposition: the movement of plant-derived carbon into the soil surrounding roots.

So the plant is not merely sitting above the soil.

It is actively pumping recently captured carbon into the underground ecosystem.

That is the real meaning behind the “carbon tunnel”: living vegetation forms a direct biological pathway between sunlight and soil life.

Root exudates: carbon released while the plant is still alive

Roots release a complex mixture of substances into the rhizosphere, including:

• simple sugars;
• amino acids;
• organic acids;
• mucilage;
• enzymes;
• secondary metabolites;
• signalling compounds;
• and cells shed from growing root surfaces.

These materials are not all deliberately “paid” to microbes in a simple trade, but collectively they create an energy-rich zone around the root.

Microorganisms respond rapidly to these carbon compounds. Some multiply near the root. Some help liberate phosphorus or micronutrients. Some form direct symbioses. Others compete with or inhibit potential pathogens.

Root exudates therefore move energy, matter and information between the plant and the soil community.

This is why a living root can influence soil differently from dead compost alone.

Compost adds carbon and nutrients.

A living root continuously delivers fresh carbon at a precise biological interface.

Carbon does not simply become “organic matter”

The older story of soil carbon was often presented like this:

Plant residue enters the soil, partly decomposes and eventually becomes stable humus.

That is only part of the story.

Microbes consume plant-derived compounds and convert them into microbial biomass. Those organisms eventually die, leaving behind microbial cell walls, fragments and other residues known as microbial necromass.

A substantial portion of persistent soil organic carbon may come not from recognisable pieces of plants, but from material that microbes processed first.

This has led to the concept of the microbial carbon pump:

1. Plants deliver carbon.
2. Microbes consume and transform it.
3. Microbial residues interact with minerals and aggregates.
4. Some of that carbon becomes physically or chemically protected.

In other words, microbes do not merely destroy organic matter.

They help manufacture new forms of soil organic matter.

Soil structure can protect carbon

Carbon persists in soil for different reasons.

Some compounds are chemically difficult to decompose, but much soil carbon survives because organisms cannot easily reach it.

Carbon may become:

• enclosed within stable aggregates;
• attached to clay or metal-bearing mineral surfaces;
• located in tiny pores inaccessible to larger organisms;
• deposited deeper in the soil profile;
• or protected by conditions that slow microbial activity.

This means soil structure is not separate from carbon cycling.

Structure helps determine whether carbon is rapidly consumed, temporarily stored or protected over longer periods.

Roots, fungal hyphae, microbial polysaccharides and soil fauna all contribute to aggregate formation. Some root-exuded polysaccharides can also help bind soil particles and influence aggregation.

So when we build structure, we are not merely making the soil softer.

We are constructing habitat, water pathways, oxygen gradients and protected spaces where carbon and nutrients can be held.

Decomposition is not failure

When organisms decompose carbon compounds, some carbon returns to the atmosphere as carbon dioxide through respiration.

That is not automatically a loss caused by poor management.

Respiration is fundamental to life.

Plants respire.

Microbes respire.

Animals respire.

The goal of a healthy soil is not to lock every carbon atom away forever. It is to maintain a productive flow in which plants continually capture carbon while enough is retained to support soil structure, biological activity and long-term fertility.

A soil with no respiration would not be a thriving soil.

It would be biologically inactive.

The important question is not:

Is carbon leaving?

It is:

Is the system capturing, cycling and retaining enough carbon to maintain and improve its function?

Nitrogen: abundant in the air, scarce to plants

The atmosphere contains an enormous quantity of nitrogen gas, but most plants cannot use nitrogen in that form.

The two nitrogen atoms in atmospheric N₂ are held together by a strong bond. Before plants can use that nitrogen to build chlorophyll, enzymes, proteins and DNA, it must be transformed into reactive compounds such as ammonium or nitrate.

That transformation depends heavily on microorganisms.

1. Nitrogen fixation

Nitrogen-fixing microorganisms convert atmospheric nitrogen gas into ammonia or related biologically useful forms.

Some live freely in soil or water.

Others form close relationships with plants.

The best-known examples are rhizobia associated with legumes, but nitrogen fixation is performed by several groups of bacteria and archaea in different habitats.

The plant does not create nitrogen.

The microbe does not create nitrogen either.

The organism spends considerable energy breaking the bond in atmospheric nitrogen and bringing that nitrogen into the biological cycle.

This is another reason carbon and nitrogen cannot be understood separately: biological nitrogen fixation requires energy, and that energy ultimately comes from carbon compounds captured by photosynthesis.

2. Assimilation

Plants absorb ammonium and nitrate through their roots and incorporate the nitrogen into organic molecules.

Microbes also assimilate inorganic nitrogen.

Once inside a living organism, nitrogen may become part of:

• amino acids;
• proteins;
• nucleic acids;
• chlorophyll;
• enzymes;
• cell membranes;
• or many other biological compounds.

Nitrogen is now temporarily stored in living tissue.

3. Immobilisation

When microbes take plant-available nitrogen from the soil and incorporate it into their bodies, the process is called immobilisation.

The nitrogen has not vanished.

It has moved from an inorganic pool into microbial biomass.

This often occurs when microbes are decomposing carbon-rich material that contains relatively little nitrogen, such as straw, sawdust or woodchips.

They need nitrogen to build proteins and reproduce, so they draw available nitrogen into their cells.

To a gardener, the plants may temporarily appear nitrogen-starved.

But within the wider cycle, the nitrogen is being held by living organisms rather than necessarily being permanently lost.

As microbes die or are eaten, some of that nitrogen can return to plant-available forms.

4. Mineralisation and ammonification

Organic nitrogen in dead roots, leaves, manure, proteins and microbial bodies cannot always be absorbed directly by plants.

Decomposer organisms break those materials apart.

Through mineralisation—more specifically ammonification—organic nitrogen is converted into ammonium.

This is a critical transition:

Nitrogen locked in organic material becomes part of the mineral nutrient pool again.

Temperature, moisture, oxygen, carbon availability and the chemistry of the material all influence how quickly this happens.

5. Nitrification

Under suitable conditions, specialised microorganisms oxidise ammonium first to nitrite and then to nitrate.

This process is called nitrification.

Nitrate is readily absorbed by many plants, but it is also highly mobile in water because it does not bind strongly to many soil surfaces.

That creates both opportunity and vulnerability.

If roots are active when nitrate is produced, it may be captured.

If nitrate accumulates when plants are absent, rainfall or excessive irrigation may carry it below the root zone.

This is one reason continuous living roots are so valuable: they maintain biological demand and give mobile nutrients somewhere to go.

6. Denitrification

In low-oxygen microsites, certain microorganisms use nitrate as an alternative electron acceptor during respiration.

They convert nitrate through several gaseous forms, potentially ending with nitrogen gas returning to the atmosphere.

This process is known as denitrification.

It completes the broad nitrogen cycle, but it can also remove valuable nitrogen from an agricultural system. If the process stops before reaching nitrogen gas, it may release nitrous oxide, a powerful greenhouse gas.

Waterlogged, compacted or carbon-rich oxygen-limited zones can encourage denitrification, although the process can also occur in tiny anaerobic microsites within otherwise aerated soil.

This shows why “more oxygen” or “more carbon” cannot be treated as universal rules.

Soil contains a mosaic of conditions.

Different organisms perform different reactions within that mosaic.

7. Volatilisation and leaching

Nitrogen can also leave the root zone without completing a useful biological loop.

Ammonia may volatilise into the atmosphere under certain conditions, particularly when ammonium-producing materials remain exposed at the surface and pH, temperature and moisture favour gaseous loss.

Nitrate may leach downward with water.

These pathways turn a relatively closed biological cycle into an open, leaky system.

Modern high-input agriculture can produce large pools of reactive nitrogen that are vulnerable to these losses.

The regenerative aim is not merely to add nitrogen.

It is to improve nitrogen capture, timing, biological storage and recirculation.

The carbon-to-nitrogen relationship

Carbon supplies energy and structural material.

Nitrogen is essential for proteins, enzymes and growth.

Decomposer organisms need both.

This is why the carbon-to-nitrogen ratio of organic matter influences decomposition.

A nitrogen-rich material such as young green foliage may decompose rapidly and release nitrogen relatively quickly.

A carbon-rich material such as dry straw or woody residue may encourage microbes to immobilise available nitrogen while they break it down.

Neither material is inherently good or bad.

They perform different functions.

Carbon-rich inputs may:

• build longer-lasting organic matter;
• protect the surface;
• support fungal pathways;
• improve structure;
• and release nutrients slowly.

Nitrogen-rich inputs may:

• drive rapid microbial growth;
• accelerate decomposition;
• and provide quicker nutrient release.

Healthy systems combine materials over time rather than expecting one input to perform every role.

The microbial loop: nutrients released through predation

Bacteria and fungi often contain a higher concentration of nutrients than their predators require.

When protozoa, nematodes and other soil organisms consume them, the predators use what they need and release some of the excess nitrogen and other nutrients into the surrounding soil.

This is sometimes called the microbial loop.

The sequence looks like this:

Plant feeds microbes → microbes capture nutrients → predators eat microbes → excess nutrients are released near roots

This is one of the reasons diversity matters.

A soil filled with bacteria but lacking grazers may behave differently from a food web containing bacteria, fungi, protozoa, nematodes, microarthropods and larger organisms.

Nutrient availability is not controlled by the presence of microorganisms alone.

It depends on feeding relationships.

Phosphorus: plentiful, but often unavailable

Many soils contain considerable total phosphorus, yet only a small fraction may be immediately available to plants.

Phosphorus can become:

• bound to calcium in alkaline conditions;
• associated with iron and aluminium compounds in acidic soils;
• held in organic matter;
• contained within living cells;
• or adsorbed onto mineral surfaces.

Unlike nitrate, phosphorus generally moves only short distances through soil.

Plants therefore depend heavily on root exploration, root hairs, organic acids, phosphatase enzymes and microbial partnerships.

Mycorrhizal fungi can extend the effective reach of roots through fine hyphal networks, accessing small pores and soil volumes that roots may not reach efficiently.

Root exudates and microbial activity can also alter phosphorus chemistry and help mobilise some otherwise inaccessible pools.

So phosphorus fertility is not merely:

How much phosphorus is present?

It is:

In what form, in what location, under what chemistry, and with which biological partners?

Sulfur: continually changing form

Sulfur is needed for certain amino acids, vitamins and enzymes.

It enters soil through minerals, organic residues, rainfall, irrigation and amendments.

Like nitrogen, much soil sulfur may be stored in organic matter.

Microorganisms mineralise organic sulfur into sulfate, the form most commonly taken up by plants.

Under oxygen-limited conditions, other microbes may reduce sulfate into sulfide compounds. When oxygen returns, sulfur-oxidising organisms can transform reduced sulfur again.

Sulfur cycling is therefore closely tied to:

• oxygen;
• water saturation;
• microbial metabolism;
• organic matter;
• and redox conditions.

The smell of rotten eggs from waterlogged organic matter is often associated with hydrogen sulfide, a sign that strongly reducing processes are occurring.

This does not mean every anaerobic process is harmful. Wetlands rely on them.

It means the suitable process depends on the habitat and the organism being grown.

Minerals: from rock to life and back again

Calcium, magnesium, potassium, iron, manganese, zinc, copper, boron and other elements do not originate in compost alone.

Many ultimately come from rocks, sediments, atmospheric deposits or water.

Weathering slowly releases mineral elements through:

• water;
• temperature change;
• root pressure;
• carbonic and organic acids;
• microbial metabolites;
• fungal activity;
• and physical fragmentation.

Once released, a mineral may:

1. dissolve in soil water;
2. bind to clay or organic matter;
3. enter a microbe;
4. enter a plant root;
5. move into an animal;
6. return through litter, manure or death;
7. become bound again;
8. or leave through erosion, harvest or leaching.

Minerals therefore cycle, but unlike carbon and nitrogen, the mineral elements themselves are not created or destroyed biologically.

Their forms, locations, oxidation states and availability change.

Redox controls mineral behaviour

This is where the name The Redox Garden becomes literal.

Redox reactions involve transfers of electrons.

In soil, oxygen availability, microbial respiration, moisture and organic matter influence which compounds accept or donate electrons.

As soil becomes increasingly oxygen-limited, microorganisms begin using alternative electron acceptors.

This can change the chemical form and solubility of elements such as:

• nitrogen;
• manganese;
• iron;
• sulfur;
• and carbon.

For example, iron may shift between oxidised and reduced forms. That can affect its own mobility and the behaviour of phosphorus attached to iron compounds.

Manganese can undergo similar changes.

Sulfur may move between sulfate and sulfide forms.

Nitrogen may move through nitrate, nitrite, gaseous intermediates and nitrogen gas.

Redox is therefore not an abstract force added to the soil.

It is a way of describing the chemical and biological state produced by energy use, electron movement, oxygen conditions and microbial metabolism.

Water: the carrier connecting the cycles

Water is not merely something plants drink.

It is:

• a reactant in photosynthesis;
• the medium in which nutrients dissolve;
• the transport system inside plants;
• a driver of weathering;
• a regulator of microbial activity;
• a creator of aerobic and anaerobic microsites;
• and a pathway through which nutrients may either be captured or lost.

Too little water slows biological activity and nutrient diffusion.

Too much water can displace oxygen, alter redox conditions and encourage nutrient losses.

The goal is not maximum water.

It is a structure that can:

• absorb rainfall;
• drain excess water;
• retain useful moisture;
• maintain air-filled pores;
• and make water accessible to roots.

Water management is therefore nutrient management, carbon management and redox management at the same time.

Oxygen: essential, but not universally dominant

Gardeners often hear that healthy soil must be aerobic.

For most crop roots and many beneficial soil processes, adequate oxygen is indeed essential.

But healthy soil is not uniformly oxygen-rich at every microscopic point.

Inside aggregates, water films, decomposing residues and saturated pores, oxygen can become limited. Those zones support organisms and reactions different from those found in well-aerated pores.

A functioning soil is a three-dimensional mosaic:

• oxygen-rich channels;
• moist aggregate interiors;
• root surfaces;
• fungal highways;
• decomposing organic particles;
• mineral surfaces;
• and temporary anaerobic microsites.

Structure creates that diversity of habitat.

Compaction is damaging not merely because the soil becomes “hard,” but because it collapses the architecture through which roots, gases, water and organisms move.

Animals accelerate the cycles

Animals do not simply consume ecosystem productivity.

They transform and redistribute it.

An earthworm draws litter into the soil, fragments it, inoculates it with microorganisms and deposits casts with altered structure and nutrient chemistry.

An insect chews plant tissue into smaller particles.

A bird eats an insect and deposits nutrients elsewhere.

A grazing animal turns fibrous plant material into manure and urine.

Predators move nutrients through food webs.

Burrowing organisms create channels for roots, water and air.

Every feeding event moves carbon, nitrogen and minerals into a new body or location.

This is why nutrient cycling depends on movement as much as decomposition.

Death feeds life

The death of an organism is not the disappearance of its value.

Dead roots become channels and food.

Fallen leaves protect soil and supply carbon.

Dead microbes contribute nitrogen, phosphorus and microbial necromass.

A fallen branch becomes fungal habitat and, eventually, soil organic matter.

The process is not always rapid.

Some organisms specialise in fresh sugars.

Others attack cellulose.

Others degrade proteins.

Fewer can dismantle lignin and other complex compounds.

Succession occurs within decomposition itself.

Different communities arrive as the resource changes.

What we call decay is actually a sequence of biological handovers.

Fermentation: redirecting decomposition

Fermented plant juices and other biological extracts fit into this wider picture, but they should not be mistaken for a replacement for the soil ecosystem.

Fermentation uses microorganisms and enzymes to transform plant material under controlled conditions.

Sugars can create an osmotic pull, drawing water and dissolved compounds from plant tissues while supporting selected fermentative organisms.

During the process:

• large molecules may be partly broken down;
• organic acids and other metabolites may form;
• soluble compounds may be extracted;
• microbial populations may change;
• and the chemistry of the material may shift.

When applied appropriately, a ferment may introduce readily available organic compounds, metabolites and nutrients.

But its effect depends on:

• the starting material;
• the fermentation method;
• dilution;
• soil conditions;
• plant stage;
• oxygen;
• moisture;
• and the existing biological community.

The deeper principle is not that fermented plant juice is magic.

It is that plant biomass can be transformed and returned to the system rather than discarded.

We grow plants.

Some feed us.

Some feed animals.

Some become mulch.

Some become compost.

Some become ferments.

All can participate in cycling.

Harvest creates an open loop

Natural ecosystems recycle a large proportion of their biomass locally.

Food gardens are different because we deliberately remove produce.

Every harvested tomato, pumpkin, leaf or seed carries carbon, nitrogen, phosphorus, potassium, calcium, trace elements and water away from the garden.

That is not a problem—it is the purpose of growing food.

But it means a productive garden cannot be treated as a completely closed system.

Nutrients leave through:

• harvest;
• pruning removed off-site;
• erosion;
• leaching;
• volatilisation;
• runoff;
• and animal movement.

They return through:

• compost;
• manures;
• mulches;
• atmospheric deposition;
• biological nitrogen fixation;
• irrigation water;
• mineral weathering;
• imported foods and residues;
• and deliberate amendments.

The aim is not to pretend the garden is closed.

It is to close loops wherever practical and replace what genuinely leaves.

When cycles become leaks

A degraded system often has the same elements as a healthy one.

The difference is that the pathways are broken.

Bare soil loses carbon through heat, erosion and rapid oxidation.

Compacted soil sheds water instead of absorbing it.

Nitrate is produced when no roots are present and leaches away.

Manure accumulates in one location rather than being distributed.

Crop residue is burnt or removed.

Synthetic nutrients are applied faster than plants and microbes can capture them.

Biomass is sent to landfill.

Water moves off the property carrying soil and dissolved fertility.

These are not merely input problems.

They are flow problems.

The system receives material but cannot retain, transform or recirculate it effectively.

What cycling looks like at The Redox Garden

At The Redox Garden, the question is not simply:

What should we feed this plant?

We ask:

What cycle is weak, blocked or leaking?

If soil is bare, we restore the carbon cycle with living cover and mulch.

If water runs off, we improve structure and infiltration.

If residues accumulate, we compost, ferment or use them as surface biomass.

If nitrogen is being lost, we maintain living roots, balance carbon-rich and nitrogen-rich materials and avoid overapplication.

If minerals are present but unavailable, we examine pH, biology, moisture, roots, organic matter and the mineral form rather than simply adding more.

If the soil lacks habitat, we build structure before expecting a diverse food web to remain.

This is a systems approach.

The answer is rarely one bottle.

The garden as a living metabolism

A garden behaves less like a container and more like a metabolism.

It captures energy.

It absorbs materials.

It transforms them.

It stores some.

It releases some.

It repairs itself.

It produces waste products that become resources for other organisms.

Health depends on the coordination of those processes.

Too much input with too little biological demand creates accumulation or loss.

Too little input with excessive removal depletes the system.

Poor structure interrupts circulation.

Low diversity narrows the range of possible transformations.

The garden thrives when energy and matter can move through many connected pathways.

Nature does produce waste—but not for long

Scientifically, it would be inaccurate to say that nature produces no waste at all.

Organisms release substances they cannot use.

Some compounds accumulate.

Some materials leave ecosystems.

Some biological by-products are toxic to other organisms.

The deeper truth is this:

In diverse living systems, one organism’s by-product frequently becomes another organism’s resource.

Nature does not guarantee perfect recycling.

It creates opportunities for reuse through diversity, succession and time.

That is the principle worth copying.

A different way to see garden materials

The next time you look at:

• fallen leaves;
• weeds;
• prunings;
• spent plants;
• manure;
• wood;
• kitchen scraps;
• dead roots;
• or overripe fruit,

do not ask only:

How do I get rid of this?

Ask:

What is this made from?

Which organisms can use it?

Should it remain on the surface, enter the compost, become biochar, feed an animal, ferment, decompose in place or return in another form?

Which cycle does it belong to?

That change in thinking is the beginning of regenerative management.

Because waste is often not a substance.

It is a resource in the wrong place, in the wrong form, at the wrong concentration or disconnected from the organism capable of using it.

Nature Never Wastes Anything

A leaf captures carbon from the air.

A root delivers some of it underground.

Microbes consume it.

Predators consume the microbes.

Nutrients are released.

Plants absorb them.

Animals eat the plants.

Residues return to the soil.

Water carries compounds between them.

Minerals shift between rock, solution, biology and organic matter.

Energy moves through every transformation.

Nothing remains unchanged.

Nothing functions alone.

At The Redox Garden, we do not try to imitate a perfect circle—because ecosystems are not perfect circles.

We try to build enough life, structure and diversity that materials have somewhere useful to go.

We keep roots in the ground.

We protect the soil.

We return biomass.

We feed biological relationships.

We slow water.

We observe where nutrients accumulate and where they escape.

We turn yesterday’s growth into tomorrow’s fertility.

Because the strength of a living system is not measured only by what it contains.

It is measured by how well it can capture, transform, retain and recirculate life.

Continue Your Journey

If nutrient cycles depend upon physical habitat, the next question is:

What kind of soil structure allows these processes to occur?

Continue reading:

Soil Structure: The Foundation Beneath Everything

And after that:

Roots: The Hidden Half of Every Plant