Soil, water, and life
This section provides a friendly, non-technical overview of the interlinkages between soil, plant life, and climate change. For more detailed information on this topic, visit our page Dig deeper.
Healthy soil, healthy plants
For over 400 million years, plants have evolved to thrive without human intervention in their natural environments. Instead, they have developed alongside the microorganisms (e.g., fungi, bacteria) that share the soil with them through a mutually-beneficial relationship. Together, these microorganisms make up the soil’s microbiome. When plants produce energy like sugars and starches from sunlight through photosynthesis, a portion of the energy is sent down to their roots. Some of this energy is then released into the soil surrounding the roots, where it nourishes the microorganisms that are beneficial to the plant while minimising microorganisms that are harmful to it.
These beneficial microorganisms protect the roots and help deliver necessary nutrients to the plants. For example, bacteria can help ensure that soil has plenty of nitrogen, a vital nutrient for healthy plant growth, by converting nitrogen in the air into nitrogen-containing compounds that plants can access. Other microorganisms like fungi grow and build expansive networks within the soil. These networks build healthy soils structure that air, water, and nutrients can easily pass through. This relationship between plants and microorganisms can sustain itself indefinitely.
On a macroscopic (i.e., visible) level, organisms like earthworms and spiders contribute to healthy soils as well. These creatures make networks of tunnels as they furrow through the ground, which loosen the soil so that water, air, and plant roots can easily penetrate the soil. They also feed on organic matter in the soil, aiding with decomposition so that nutrients are recycled back into the soil for plant roots and other organisms (both micro and macro) to utilise.
Through this give-and-take cycle, there is no need for external assistance such as fertilisers or pesticides for robust plant growth. That’s why we say…
“Feed the soil, not the plants.”
These beneficial microorganisms protect the roots and help deliver necessary nutrients to the plants. For example, bacteria can help ensure that soil has plenty of nitrogen, a vital nutrient for healthy plant growth, by converting nitrogen in the air into nitrogen-containing compounds that plants can access. Other microorganisms like fungi grow and build expansive networks within the soil. These networks build healthy soils structure that air, water, and nutrients can easily pass through. This relationship between plants and microorganisms can sustain itself indefinitely.
On a macroscopic (i.e., visible) level, organisms like earthworms and spiders contribute to healthy soils as well. These creatures make networks of tunnels as they furrow through the ground, which loosen the soil so that water, air, and plant roots can easily penetrate the soil. They also feed on organic matter in the soil, aiding with decomposition so that nutrients are recycled back into the soil for plant roots and other organisms (both micro and macro) to utilise.
Through this give-and-take cycle, there is no need for external assistance such as fertilisers or pesticides for robust plant growth. That’s why we say…
“Feed the soil, not the plants.”
Soil and climate change
Healthy soils with rich microbiomes also help tackle climate change through a process called carbon sequestration. Carbon sequestration reduces the amount of carbon dioxide, the most abundant of the greenhouse gasses that drive climate change, in the atmosphere. In this process, plants deliver carbon dioxide from the atmosphere into the soil through their roots. Microorganisms then play a crucial role by breaking down this carbon dioxide into compounds that can be safely stored in the soil and used by other life forms. You can see a (very simplified!) illustration of carbon sequestration in the graphic to the side.
Sadly, climate change and conventional farming threaten the development and very existence of healthy soil microbiomes. Rising temperatures affect the activity levels and lifecycles of microorganisms in unpredictable ways, and each is affected differently. Synthetic fertilisers that are widely used in both large- and small-scale conventional agriculture suppress the activity of bacteria that aid with nitrogen cycling. The effects on individual species of microorganisms are problematic in and of themselves, but the issue doesn’t stop there. Soil microbiomes are extremely complex networks made up of billions of life forms working in harmony, with each dependent on the others to be able to function properly. Therefore, when even one of these life forms is altered, the existence of the entire microbiome is threatened. And perhaps even more distressing, rising global temperatures from climate change will actually lead to soils releasing more carbon into the atmosphere rather than storing it, which will advance the rate of climate change.
Another substantial threat to soil health is soil compaction. This issue is especially problematic is many sub-Saharan countries like Malawi. Soil compaction is central to Tiyeni’s work, so we think it deserves its own section!
Sadly, climate change and conventional farming threaten the development and very existence of healthy soil microbiomes. Rising temperatures affect the activity levels and lifecycles of microorganisms in unpredictable ways, and each is affected differently. Synthetic fertilisers that are widely used in both large- and small-scale conventional agriculture suppress the activity of bacteria that aid with nitrogen cycling. The effects on individual species of microorganisms are problematic in and of themselves, but the issue doesn’t stop there. Soil microbiomes are extremely complex networks made up of billions of life forms working in harmony, with each dependent on the others to be able to function properly. Therefore, when even one of these life forms is altered, the existence of the entire microbiome is threatened. And perhaps even more distressing, rising global temperatures from climate change will actually lead to soils releasing more carbon into the atmosphere rather than storing it, which will advance the rate of climate change.
Another substantial threat to soil health is soil compaction. This issue is especially problematic is many sub-Saharan countries like Malawi. Soil compaction is central to Tiyeni’s work, so we think it deserves its own section!
Soil compaction
Soil compaction has threatened the natural environment and farming outputs since the dawn of agriculture, and is almost exclusively caused by man-made activities such as footfall, machinery, and tilling. When soil is compacted it means that soil becomes more dense; there are fewer “pores” in the soil for roots, air, and water to penetrate into the land. The water that is able to penetrate into the soil has limited movement due constricted “pore” spaces. Compacted soil also has less capacity to store water in reserve, which would help provide plants and other life within the soil with resilience during dry spells.
These outcomes in turn lead to high levels of rainwater runoff, degraded soil structure and erosion, and decreased soil fertility. Because plant roots are unable to grow down into the earth they grow sideways instead, leading to stunted growth and greater vulnerability to uprooting during extreme weather. Microorganisms are unable to survive or maintain their regular levels of activity in these conditions. They are therefore cannot carry out the beneficial actions described above that would otherwise remedy the issues caused by soil compaction.
While it is true that soil compaction and erosion are interlinked, many of these outcomes have been attributed solely to soil erosion throughout much of history, as people can clearly see it happening. Soil compaction, on the other hand, takes place below the land’s surface, making its existence and impacts less apparent to the observer
While it is true that soil compaction and erosion are interlinked, many of these outcomes have been attributed solely to soil erosion throughout much of history, as people can clearly see it happening. Soil compaction, on the other hand, takes place below the land’s surface, making its existence and impacts less apparent to the observer
In Malawi, soil compaction poses an especially severe threat to soil health, agriculture and, as a result, the >80% of the population that relies on smallholder farming for their livelihoods. Compaction has been caused and intensified by decades of unsustainable conventional farming. Conventional practices involve creating a series of mounds across slopes with pathways between them. Footfall and repeated hoeing further compact the soil, while pathways intensify water runoff by serving as channels for rainwater to run down slopes. There have been efforts since the early-to-mid-20th century to identify and publicise the issue of soil compaction. However, a combination of socio-cultural practices and official policy in Malawi, both before and after its independence, impeded the uptake of alternative practices that would address the issue of soil compaction.
In the 1990s, the agronomist Francis Shaxson engaged in collaborative research with the UN Food and Agriculture Organization (FAO) and the Malawi Soil Fertility Initiative to investigate Malawi’s declining soil health and crop yields. The resulting 1999 report identified a compacted layer of soil, initially dubbed “hoe pan” but now largely referred to as “hardpan”. The hoe pan was pinpointed as a “simple but surprisingly unrecognized problem”, and breaking this compacted soil layer was highlighted as “one of the requirements for raising crop yields throughout much of Malawi…[which] cannot all be solved simply through the increasing use of hybrid maize seed and chemical fertiliser”. Shaxson and his research would soon prove instrumental to the development of Deep Bed Farming and its use as a solution for regenerating Malawi’s declining soil and empowering smallholder farmers to build self-sustaining livelihoods.
In the 1990s, the agronomist Francis Shaxson engaged in collaborative research with the UN Food and Agriculture Organization (FAO) and the Malawi Soil Fertility Initiative to investigate Malawi’s declining soil health and crop yields. The resulting 1999 report identified a compacted layer of soil, initially dubbed “hoe pan” but now largely referred to as “hardpan”. The hoe pan was pinpointed as a “simple but surprisingly unrecognized problem”, and breaking this compacted soil layer was highlighted as “one of the requirements for raising crop yields throughout much of Malawi…[which] cannot all be solved simply through the increasing use of hybrid maize seed and chemical fertiliser”. Shaxson and his research would soon prove instrumental to the development of Deep Bed Farming and its use as a solution for regenerating Malawi’s declining soil and empowering smallholder farmers to build self-sustaining livelihoods.
Water resources and management
Rainwater needs to be able to penetrate into the soil to recharge aquifers, layers beneath the Earth’s surface with the ability to store high levels of usable groundwater. Groundwater refers to all water present below Earth’s surface. Approximately 30% of all the world’s freshwater is from groundwater. Of the other 70%, almost 69% is held in ice caps and glaciers. Only 1% of freshwater comes from sources like rivers and lakes, demonstrating just how important groundwater resources are! The point beneath the Earth where the ground becomes fully saturated by groundwater is called the water table. The water table fluctuates around variables such as climate, precipitation, and the ability for above-ground surface water sources such as rain or snow to seep downward into the Earth.
A process called groundwater recharge is necessary to maintain these vital groundwater resources and a healthy water table. During groundwater recharge, water from above the Earth’s surface moves downward, entering aquifers. Most of this surface water comes from rain or melting snow. For this essential process to happen successfully, the water above Earth’s surface needs healthy, loose soil with lots of pores to be able to move downward. Surface water that would normally recharge groundwater levels will instead experience high levels of surface runoff if soil is too compacted.
A process called groundwater recharge is necessary to maintain these vital groundwater resources and a healthy water table. During groundwater recharge, water from above the Earth’s surface moves downward, entering aquifers. Most of this surface water comes from rain or melting snow. For this essential process to happen successfully, the water above Earth’s surface needs healthy, loose soil with lots of pores to be able to move downward. Surface water that would normally recharge groundwater levels will instead experience high levels of surface runoff if soil is too compacted.
Even with the healthiest soil there is a limit to how quickly surface water can permeate downward to reach aquifers. But don’t let that discourage you! There are very simple ways to maximise the ability for surface water to reach aquifers to help with groundwater recharge. One way is through rainwater harvesting, one of the oldest and easiest methods of maintaining self-supplies of water for households. In rainwater harvesting, rain is collected and stored in some form of containment. If the containment is built right into the ground, such as by digging a simple ditch, large quantities of rainwater can be collected and allowed to slowly seep into the Earth. Harvesting rainwater this way recharges groundwater, contributing to sustainable groundwater management, while also minimising water runoff. Tiyeni’s climate-smart agriculture method, Deep Bed Farming, incorporates rainwater harvesting, and is able to capture over 90% of rainfall!
Click the buttons below to learn more about Deep Bed Farming or to see some facts and figures of how this farming method contributes to the delicate but crucial balance between soil, water, and life. If your curiosity about soil science has been piqued (and we hope is has been!), you can also click below to check out our “Dig deeper” page.
Click the buttons below to learn more about Deep Bed Farming or to see some facts and figures of how this farming method contributes to the delicate but crucial balance between soil, water, and life. If your curiosity about soil science has been piqued (and we hope is has been!), you can also click below to check out our “Dig deeper” page.
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