Beneath every forest, field and meadow lies a living world that quietly sustains life on Earth. More than dirt, this living world acts as natural thermal buffer – a giant shock absorber for temperature. It stores carbon, regulates water, supports biodiversity and provides the nutrients that forests and crops need to grow.
However, across many parts of the world, soils are losing their ability to buffer heat. This hidden environmental problem may already be affecting crops, ecosystems, and even local climate patterns, because moist soil absorbs solar energy gradually, while dry soil heats rapidly and releases heat back into the air.
When soil loses moisture, organic content, structure, it loses much of this buffering power, causing the ground temperatures to rise rapidly and intensify the effects of climate change. This, in turn, can reduce plant growth, lower crop and pasture production, and even affect local weather and climate over large areas. Therefore, protecting soil has become increasingly important in an age where climate change intensifies weather extremes.
Healthy Soil and Climate Resilience: Heatwaves and Drought Stress
Healthy soil can help farmers manage droughts and floods, while forest soils play a significant role in storing carbon and regulating the global climate. Conversely, damaging soil through intensive harvesting, excessive tillage and the removal of organic matter can weaken these natural defences.
Across many parts of the world, including Australia, scientists are discovering that soils are losing their ability to buffer heat. This hidden environmental problem may already be affecting crops, ecosystems, and even local climate patterns, as moist soil absorbs solar energy gradually, while dry soil heats rapidly and releases heat back. This means degraded soil can intensify heatwaves and increase drought stress. The result of soils losing their buffering capacity can be alarming because:
- Plant roots become stressed
- Crop growth slows
- Soil microorganisms decline
- Moisture evaporates faster
- Pasture productivity decreases
- Local temperatures may rise
In extreme cases, degraded soils can even contribute to worsening regional climate conditions. This is true, particularly, during the heatwaves, when the roots of crop plants may be sitting in rapidly heating soil. In a healthy and fully functioning condition, soil acts as silent climate shield.
Yet this vital resource is often overlooked until erosion strips it away, drought dries it out or heavy rainfall washes it into rivers. And when organic matter disappears and moisture declines, the land loses this protective shield.
What Is a “Thermal Gap” in Soil?
Researchers have introduced the idea of a “thermal gap.” This refers to difference between a soil’s natural ability to regulate temperature by keeping it steady and what it actually doing today after years of intensive farming, land use change, vegetation loss, overgrazing, and climate change. Healthy soil naturally resists rapid temperature swings. It stores water, shades roots, slows heat movement. Damaged soil heats up quickly under sun, expose plant roots to dangerous temperatures.
In simple terms, the thermal gap shows how much cooling power the soil has lost. Large areas of southeastern and central Australia now display significant thermal gaps. The soil there is no longer protecting crops and vegetation from heat as effectively as it once could.
Why Some Soils Stay Cooler Than Others
Nature has designed soil to function like a sponge and a blanket at the same time. More than dirt, it stores water while insulating roots from harsh environmental changes. Therefore, healthy soil plays a powerful role in balancing Earth’s climate system. It protects farms from extreme heat, acting like natural underground air conditioner. It is one of Earth’s most important climate regulators, controlling how heat and moisture move between the land and the atmosphere.
But not all soils respond to heat the same way. A clay-rich soil generally performs better. It can hold more water, and warm or cool slowly, creating a more stable or steadier underground environment for plant roots. Certain iron-rich red and yellow soils in northern Australia, known as Kandosols, also show strong natural buffering ability. In many areas, these soils still function effectively as natural heat regulators.
Sandy soils, on the other hand, behave very differently, because they cannot retain much moisture. When ground cover is low, they lose water faster and dry out rapidly under hot conditions. When the soil becomes dry, bare, damaged and compacted, or degraded, that natural protection weakens dramatically.
Once dry, they absorb heat quickly. Sunlight directly heats the ground surface. Roots suffer stress, soil biology slows down, and crops may begin declining before visible symptoms are obvious above ground. This is one reason why flash droughts are so dangerous. A flash drought can develop in days or weeks when high temperatures, dry winds and low soil moisture arrive together. This difference explains why “hot and dry” conditions are more dangerous than simple dryness alone.
A clay-rich soil generally performs better. It can hold more water, and warm or cool slowly, creating a more stable or steadier underground environment for plant roots. Rich in water or moisture, and organic matter such as leaf litter, roots, and microbial life, it slows sudden temperature changes by absorbing and storing heat slowly and helps regulate the surrounding environment, protecting plants from sudden temperature extremes.
1. Forest Soils: A Hidden Storehouse of Carbon
Forests are widely recognised for absorbing carbon dioxide from the atmosphere. Trees capture carbon through photosynthesis and store it in their trunks, branches, leaves and roots. However, an equally important carbon reservoir lies beneath the forest floor.
Forest soils store an estimated 40% of the world’s terrestrial carbon, making them a critical component of the global carbon cycle. Fallen leaves, dead branches, roots and other organic materials gradually decompose, adding carbon to the soil and supporting an intricate community of microorganisms. This underground ecosystem helps maintain soil fertility, water retention and nutrient cycling. When forest soils remain relatively undisturbed, they continue storing carbon over long periods.
However, harvesting practices can disrupt this process. Removing organic matter, disturbing the forest floor and compacting the soil may reduce carbon storage and interfere with the natural processes that support forest regeneration. The consequences extend beyond individual forests. When soil carbon is lost, some of it may return to the atmosphere as carbon dioxide, contributing to climate change.
2. What Twenty Years of Forest Research Reveals
The British Columbia Long-Term Soil Productivity (BC-LTSP) study provides valuable evidence about how forest management influences soil carbon over time. Researchers examined 12 forest sites across four biogeoclimatic zones in British Columbia, Canada. They investigated how soil compaction and the removal of organic material affected soil carbon following timber harvesting.
Soil samples were collected before harvesting and again five, ten and twenty years later. This long-term approach allowed researchers to compare different harvesting practices and observe how soil carbon changed over time. Two harvesting methods were particularly important:
– Stem-only harvesting: Tree trunks are removed while branches, foliage and other harvest residues remain on the site.
– Whole-tree harvesting: Trees and much of their above-ground residue are removed, reducing the organic material returned to the forest floor.
The researchers also examined plots where the forest floor was completely removed. The findings revealed substantial differences between these practices.
Keeping the forest floor intact protects carbon:
Where the forest floor remained intact, carbon in that layer declined by only 5% after twenty years. Meanwhile, carbon in the underlying mineral soil increased by 14%. Stem-only harvesting also preserved approximately 15% more forest floor carbon than whole-tree harvesting. These findings highlight the value of retaining organic material rather than removing as much vegetation residue as possible.
Removing organic matter can cause prolonged losses:
The most severe losses occurred where both harvest residues and the forest floor were removed. Total soil carbon declined by 52% within five years and remained 33% below preharvest levels after twenty years. Recovery was slow and varied considerably among sites.
Researchers estimated that soil carbon could take approximately 22–86 years to return to its preharvest level where the forest floor had been completely removed. These results demonstrate that the effects of forest harvesting can persist for decades. Even when trees begin growing again, the recovery of underground carbon stores may take much longer. The research, published in the Journal of Geophysical Research: Biogeosciences, underscores the importance of protecting forest soils during timber operations.
3. Healthy Soil Can Help Agriculture Withstand Extreme Weather
The importance of soil health extends far beyond forests. Agricultural fields also depend on the soil’s ability to absorb water, retain moisture and supply nutrients. Farmers cannot control when rain falls, how long a drought lasts or how severely temperatures fluctuate. They can, however, improve the condition of the soil in which their crops grow. Consider two contrasting weather conditions.
During dry periods, crops depend on moisture stored in the soil. During intense rainfall, the soil must absorb water quickly enough to limit runoff, erosion and waterlogging. Healthy soil can perform both functions more effectively because its structure contains interconnected spaces that allow water and air to move while helping retain moisture. Soil rich in organic matter can also support beneficial microorganisms, improve aggregation and maintain nutrient availability.
By contrast, degraded soil with poor structure may absorb water slowly, lose valuable topsoil during storms and struggle to provide crops with sufficient moisture during dry spells. This distinction becomes increasingly important as climate change contributes to more severe and unpredictable weather in many regions.
The difference between dirt and living soil:
The terms dirt and soil are sometimes used interchangeably, but they express an important distinction in agricultural practice. Healthy soil is a living system containing mineral particles, organic matter, water, air, roots and countless organisms. These components interact to support plant growth and ecological processes.
Degraded soil may have low organic matter, poor structure and limited biological activity. Such conditions can increase dependence on external inputs and make crops more vulnerable to environmental stress. The goal of sustainable agriculture is therefore not simply to keep land productive for another growing season. It is to maintain and improve the biological and physical processes that allow the soil to remain productive over time.
4. How Soil Organic Matter Helps Manage Droughts and Floods
Organic matter is one of the most important components of healthy soil. It develops from decomposing plant residues, roots and other biological material. It contributes to soil aggregation, supports microorganisms and improves the soil’s ability to retain water and nutrients.
When organic matter and soil structure are well maintained, rainfall can infiltrate the ground more effectively. This can reduce surface runoff and help replenish soil moisture. During dry weather, the water retained in the soil can help sustain crops between rainfall events, although the amount available to plants depends on soil texture, rooting depth, climate and other conditions. The benefits are particularly relevant in agricultural areas exposed to alternating droughts and heavy rainfall.
During heavy rainfall well-structured soil can improve water infiltration. Reduce surface runoff and soil erosion. Help protect waterways from sediment and nutrient pollution. Support root systems and soil organisms. These benefits depend on the soil’s condition and the intensity of the rainfall. Even healthy soil can become saturated during prolonged or exceptionally heavy storms.
During drought, healthy soil can retain moisture for longer periods. Support deeper and more effective root development where conditions permit. Improve nutrient cycling and soil biological activity. Help crops tolerate periods of limited rainfall. Soil health cannot eliminate drought, but it can strengthen the natural capacity of agricultural land to cope with water shortages.
5. Cover Crops and Reduced Tillage: Practical Ways to Protect Soil
Farmers can improve soil health through management practices that retain organic material, minimise unnecessary disturbance and keep the ground protected.
Cover crops:
Cover crops are grown primarily to protect and improve the soil rather than for direct harvest. Depending on the species and local conditions, they can protect bare ground, reduce erosion, add organic residues and support beneficial soil organisms. Their roots also help create and maintain soil structure.
Leguminous cover crops may contribute nitrogen to agricultural systems, while other species can capture nutrients that might otherwise be lost. However, cover crops require careful management. In water-limited environments, their water use must be considered when selecting species and deciding when to terminate them.
Reduced tillage and no-till farming:
Frequent intensive tillage can break down soil aggregates, accelerate the decomposition of organic matter under some conditions and leave the surface vulnerable to erosion. Reduced tillage limits soil disturbance, while no-till farming avoids routine mechanical cultivation of the soil before planting.
When combined with appropriate crop rotations and residue management, these practices can help preserve soil structure and improve water infiltration. Their results vary according to climate, soil type, crop system and management. No-till alone does not guarantee an increase in soil carbon, but it can be an important part of a broader soil-health strategy.
Retaining crop residues:
Leaving suitable crop residues on the field provides surface protection against raindrop impact and reduces direct exposure to sun and wind. As residues decompose, they contribute organic material to the soil. Their presence can also help reduce evaporation and limit erosion. Together, cover crops, reduced tillage and residue retention can help build more resilient agricultural systems over time.
6. Forest Conservation and Soil Health Are Closely Connected
Forest conservation and sustainable agriculture are sometimes treated as separate environmental priorities. In reality, they are connected through the same underlying resource: soil. In forests, the organic layer protects the mineral soil, supports nutrient cycling and provides a habitat for organisms essential to ecosystem functioning. In agricultural fields, organic matter and soil structure influence crop productivity, moisture availability and resistance to erosion.
Both systems depend on the gradual return and decomposition of organic material. When forest harvesting removes too much organic matter, carbon stores may decline and soil recovery can take decades. When agricultural practices repeatedly expose and disturb the soil, erosion and degradation can reduce its long-term productive capacity.
The lesson is not that all disturbance must be eliminated. Forests need carefully planned management, and farms must be cultivated to produce food. Rather, management should recognise the ecological functions of soil and avoid unnecessary damage. Responsible forest harvesting, retention of suitable residues, protection of the forest floor and sustainable agricultural practices can help maintain the natural processes on which both ecosystems depend.
7. Why These Lessons Matter for Climate-Vulnerable Regions
The importance of soil health is especially clear in regions experiencing water scarcity, intense rainfall, flooding and land degradation. In Pakistan, for example, communities face the combined challenges of irregular rainfall, heat extremes, floods and pressure on natural resources. Agricultural land and forested mountain slopes are both vulnerable when vegetation cover and soil structure deteriorate.
In mountainous areas, removing vegetation and disturbing soil can increase erosion risks, particularly on steep slopes. In agricultural plains, poor soil structure can contribute to runoff, while limited soil moisture can intensify the effects of drought. Local conditions determine which practices are most suitable, but several principles apply widely:
– Protect the soil surface with vegetation or suitable organic residues.
– Reduce unnecessary soil disturbance.
– Maintain trees and natural vegetation where ecologically appropriate.
– Use cover crops and crop rotations suited to local rainfall and water availability.
– Prevent uncontrolled erosion and protect streambanks.
– Retain forest residues where appropriate and avoid unnecessary removal of the forest floor.
– Monitor soil organic matter and other indicators of soil health over time.
These measures are not substitutes for climate mitigation, water management or disaster preparedness. They are complementary strategies that strengthen the natural systems on which communities depend.
Conclusion: Protect the Soil, Protect the Future
The ground beneath our feet is one of nature’s most important but frequently overlooked resources. Forest soils store vast quantities of carbon, while healthy agricultural soils help regulate water, sustain crops and support biodiversity. Long-term research from British Columbia demonstrates the potential consequences of removing forest organic matter. Where both harvesting residues and the forest floor were removed, soil carbon suffered substantial losses that persisted for at least twenty years. By comparison, retaining the forest floor and more organic material helped preserve carbon.
Agricultural soil management offers a complementary lesson. Cover crops, reduced tillage, residue retention and other locally appropriate practices can improve soil structure, support organic matter and help farms cope with changing rainfall patterns. Neither forests nor farms can escape every consequence of climate change. Yet protecting soil gives these ecosystems a stronger foundation for recovery and resilience. Healthy soil is more than a resource for producing timber or food.
It is a living climate asset, a reservoir of carbon, a natural water manager and a foundation for ecological balance. If we want forests that recover, farms that endure and landscapes that remain productive for future generations, we must begin by protecting the living world beneath our feet.
At The Secrets of Nature, we believe that nature is not merely something to observe; it is a living system to understand, respect and protect. Caring for the soil is one of the most practical ways to honour that responsibility.
