Soil Health: Understanding, Assessing and Managing the Living Soil

A farm’s productivity begins long before a crop is harvested.

It begins beneath the crop.

The soil supports roots, stores and moves water, cycles nutrients and provides habitat for an enormous community of organisms. How well these functions work together influences how crops establish, grow and respond to environmental stress.

This is why soil health deserves attention beyond simply asking how much fertilizer is in the soil.

A soil can contain nutrients and still have problems with:

Soil health is therefore about how well the soil functions as a system.

At UkulimaModern, soil health management forms part of a broader approach to sustainable farm productivity—connecting soil assessment, fertility management, crop nutrition, water management and appropriate agronomic practices.

«Healthy soil is not simply soil with nutrients. It is soil that functions.»

What Is Soil Health?

Soil health refers to the capacity of soil to function effectively as a living ecosystem and support plant growth while maintaining its ability to perform essential functions over time.

These functions include:

Soil health is therefore broader than a single laboratory measurement.

It is an interaction between the soil’s:

Physical condition

How the soil is structured and how water, air and roots move through it.

Chemical condition

The soil’s pH, nutrient status, salinity and other chemical properties.

Biological condition

The organisms and biological processes that contribute to nutrient cycling, decomposition and soil functioning.

These three dimensions are interconnected.

Soil Health vs Soil Fertility

The terms are often used interchangeably, but they are not exactly the same.

Soil fertility

Generally concerns the soil’s capacity to supply nutrients required for plant growth.

Soil health

Takes a broader view of how well the soil functions physically, chemically and biologically.

For example, a soil may have adequate phosphorus and potassium but still suffer from severe compaction.

The nutrient levels may look acceptable, but roots may struggle to explore the soil.

Similarly, a soil may contain sufficient nutrients but have poor organic matter and weak structure, resulting in poor water retention and infiltration.

Therefore:

«Soil fertility is part of soil health—but soil health is bigger than fertility.»

The Three Dimensions of Soil Health

A practical way to understand soil health is through three interconnected dimensions.

  1. Physical Soil Health

This concerns the physical condition of the soil.

Important characteristics include:

  1. Chemical Soil Health

This concerns the soil’s chemical environment.

Important factors include:

  1. Biological Soil Health

This concerns living organisms and biological processes within the soil.

These include:

A good soil-management programme should consider all three.

  1. Physical Soil Health

Soil Structure

Soil structure refers to how individual soil particles are arranged into aggregates.

Good structure can support:

Poor structure can result in:

Compaction

Compaction occurs when soil particles become compressed and pore spaces are reduced.

This can be caused by:

Compacted soil may restrict root growth and reduce movement of water and air.

Field signs may include:

Managing traffic, avoiding unnecessary soil disturbance and maintaining soil organic matter can help support better soil structure.

Water Infiltration

Healthy soil should allow water to enter the soil rather than simply running across the surface.

Poor infiltration can lead to:

Farmers can observe how quickly water enters the soil after rainfall or irrigation.

Very rapid runoff may indicate a structural or surface-cover problem, although infiltration should ideally be assessed more systematically when making management decisions.

Soil Erosion

Erosion removes valuable topsoil.

The topsoil often contains significant amounts of:

Once this layer is lost, restoring the productive capacity of the land can be difficult and expensive.

Signs of erosion may include:

Protecting Soil From Erosion

Depending on the farm and landscape, useful approaches can include:

The appropriate method depends on slope, soil type, rainfall and farming system.

  1. Chemical Soil Health

Chemical health is more than NPK.

A well-managed soil should have appropriate chemical conditions for the crop being grown.

Important considerations include:

pH

Influences nutrient availability and other soil processes.

Nutrient balance

Plants require a range of nutrients, not simply nitrogen, phosphorus and potassium.

EC / salinity

Excess salts can affect plant water uptake and crop performance.

Organic matter / carbon

Contributes to soil structure, nutrient cycling and biological processes.

This is why soil testing remains an important component of soil-health management.

Soil pH and Soil Health

Soil pH influences the chemical environment around plant roots.

When pH is unsuitable for a particular crop, nutrient availability can be affected.

Corrective measures may sometimes be required, but these should be based on appropriate assessment rather than simply applying lime or other amendments because a soil is suspected to be acidic.

The principle is:

«Test before correcting.»

Nutrient Balance Matters

Soil fertility is not about maximising every nutrient.

Excessive levels of some nutrients can create imbalances and may interfere with the availability or uptake of others.

For example, repeated application of one nutrient without considering the broader nutrient balance may not produce the desired crop response.

A soil-health approach therefore considers:

Availability + balance + crop demand + soil conditions.

  1. Biological Soil Health

This is one of the most fascinating aspects of soil.

Soil is alive.

It contains communities of organisms involved in:

These organisms include:

Their activity contributes to the functioning of the soil ecosystem.

Organic Matter: Fuel for the Soil System

Organic matter is one of the most important components of healthy soil.

It can contribute to:

Sources may include:

However, simply adding large quantities of organic material is not automatically beneficial.

Quality, maturity, nutrient composition, application rate and decomposition characteristics matter.

Soil Microorganisms and Nutrient Cycling

Microorganisms contribute to the transformation and cycling of nutrients within the soil.

Some organisms decompose organic materials.

Others interact with plant roots.

Certain microorganisms can contribute to processes involved in nutrient availability.

This means soil management should consider not only what is added to the soil, but also whether the management system supports the biological processes that make those resources useful.

Earthworms and Soil Health

Earthworms can contribute to soil structure and organic-matter decomposition.

Their activity can create channels through which:

Finding earthworms can therefore provide one useful field observation of biological activity.

However, the absence or presence of earthworms alone should not be used as a complete soil-health diagnosis.

Soil health requires multiple indicators.

What Can Farmers Observe in the Field?

Farmers do not always need sophisticated equipment to begin paying attention to soil health.

Useful field observations include:

Soil structure

Does the soil form stable aggregates or easily become powdery or crusted?

Root development

Are roots deep, well distributed and healthy?

Infiltration

Does water enter the soil or quickly run off?

Compaction

Is there a hard layer restricting roots?

Earthworms and soil organisms

Is there visible biological activity?

Organic residues

Is the soil protected by plant material or exposed?

Erosion

Is valuable topsoil being moved away?

Crop performance

Are plants growing evenly across the field?

These observations do not replace laboratory testing, but they provide valuable context.

The Importance of Soil Cover

Bare soil is vulnerable.

Depending on the production system, maintaining soil cover through:

can help reduce exposure to:

Soil cover can therefore form an important part of a soil-health strategy.

Mulching and Soil Health

Mulching can help:

For perennial crops and orchards, appropriate mulching can be particularly useful around the root zone.

However, mulch should be managed properly.

Avoid creating conditions that encourage pests or diseases, and do not place organic material directly against plant stems or trunks where this could create problems.

Compost and Manure

Compost and well-managed manure can contribute organic matter and nutrients.

However, farmers should consider:

More is not always better.

Organic amendments should form part of a planned soil-management strategy.

Cover Crops

Cover crops can provide several potential benefits, depending on the species and farming system.

They can help:

Cover crops should nevertheless be selected according to:

Agroforestry and Soil Health

Trees can form part of a wider soil-health strategy.

Appropriately designed agroforestry systems can contribute to:

The choice and placement of trees should consider the main crop, water requirements, root competition, farm objectives and management system.

Soil Health and Water Management

Soil and water management are closely connected.

A soil with good structure and adequate organic matter may be better positioned to:

Conversely, degraded soil can increase runoff and reduce effective water use.

This is particularly important as farmers deal with increasingly variable rainfall and periods of water stress.

Soil Health and Fertilizer Management

Improving soil health does not mean abandoning fertilizers.

It means using nutrients strategically.

A balanced approach considers:

This helps reduce unnecessary expenditure and supports more efficient nutrient use.

Can Soil Health Be Restored?

In many situations, soil condition can be improved through appropriate management.

But soil restoration is rarely an overnight process.

Depending on the problem, improvement may involve:

The appropriate intervention depends on the diagnosis.

«Do not treat symptoms without understanding the underlying soil problem.»

Common Practices That Can Degrade Soil Health

Some farming practices can contribute to soil degradation when poorly managed.

These may include:

The objective is not to label a single practice as universally good or bad.

Context and management matter.

The UkulimaModern Soil Health Management Approach

At UkulimaModern, soil health can be approached through a practical cycle:

01 — Observe

Look at the soil, crop, roots, water movement and field conditions.

02 — Assess

Identify physical, chemical and biological indicators that require attention.

03 — Test

Use appropriate soil and, where necessary, water testing to obtain objective information.

04 — Interpret

Connect laboratory results with field observations and crop requirements.

05 — Improve

Apply appropriate soil-management practices.

06 — Protect

Maintain soil cover, reduce erosion and support biological activity.

07 — Monitor

Observe changes in soil and crop performance.

08 — Adapt

Adjust management as conditions change.

«Healthy soil is built through consistent management, not a single input.»

A Practical Soil Health Checklist

Walk through your farm and ask:

Physical

☐ Is the soil compacted?

☐ Does water infiltrate effectively?

☐ Is there visible erosion?

☐ Are roots developing properly?

☐ Is the soil adequately covered?

Chemical

☐ Has the soil been tested?

☐ Is the pH appropriate for the crop?

☐ Are nutrient levels balanced?

☐ Is salinity a concern?

☐ Is organic matter being maintained?

Biological

☐ Is there visible biological activity?

☐ Are organic materials returning to the soil?

☐ Are decomposition processes occurring?

☐ Is the production system supporting soil biodiversity?

Management

☐ Is soil disturbance appropriate?

☐ Is irrigation well managed?

☐ Are fertilizers being applied based on crop and soil requirements?

☐ Are erosion-control measures in place?

☐ Is soil health being monitored over time?

Soil Health Is a Long-Term Investment

Farmers often measure productivity by looking at what is harvested today.

Soil health requires a longer view.

The soil supporting today’s crop is also the foundation for:

This is why soil management should balance current productivity with long-term soil function.

The goal is not simply to extract more from the soil.

It is to build a production system in which the soil continues to support productive agriculture.

From Soil Health to Soil Fertility Management

Understanding soil health tells us how the soil is functioning.

The next question is:

«How do we deliberately build, maintain and manage soil fertility within that system?»

That takes us to the next stage:

Whole Soil Fertility Management

Here, we move from individual nutrient recommendations to an integrated approach involving soil testing, organic matter, nutrient sources, amendments, crop requirements, water management, agroecological practices and continuous monitoring.

Work With UkulimaModern

Need help assessing the condition of your soil?

UkulimaModern supports farmers through soil assessment, testing, agronomic interpretation and practical soil-management planning.

Understand your soil. Manage it wisely. Grow sustainably.

UkulimaModern

Seedlings. Extension. Agronomy.

Rooted in Sustainability, Growing with Farmers.

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