There is more life beneath the ground than you know. Healthy soils contain a vibrant range of life forms such as protozoa, nematodes, mites, springtails, spiders, insects, bacteria, fungi, earthworms and numerous burrowing animals. This rich biodiversity plays a vital role in mitigating climate change, neutralising pests, purifying and storing water, providing antibiotics and preventing soil erosion. The well-being of all people, plants and animals depends on the complex processes that take place in soil. One square meter of soil can harbour as many as one billion organisms. Soils are home to over a quarter of all living creatures on Earth.
In the context of a human life span, soil is not normally renewable. Healthy ecosystems constantly recycle and generate fresh water and air. Soil formation however takes decades or even centuries to occur. Human activity has polluted the air and severely degraded most freshwater habitats. The ability of ecosystems to produce clean air and water has been impaired. The Earth’s healthy soils are also under attack. Intensive farming destroys the soil’s natural regenerative properties and makes it entirely dependent on artificial fertilisers. Modern industrial farming practices transform previously fertile soils into dust.
Soil quality and fertility depends on the presence of a vast biodiversity of underground living organisms. This community of creatures processes dead organic matter to produce nutrient-rich complex organic matter, called humus. Humus is necessary to sustain plants. Humus cannot be man-made. It is created by soil biodiversity. Micro-organisms play a major role in processing the organic matter in soil. Soil is the most essential food source on the planet. It provides the nutrients that plants need to grow and sustain animals, as well as produce our own food and textile fibers.
Soil organisms store and release carbon. This natural system helps the earth regulate the level of greenhouse gases in the atmosphere and their impact on the global climate system. Soil stores carbon mainly in the form of organic matter and it is one of the main carbon sinks on earth, second only to the oceans. Soils that are allowed to retain their biodiversity are therefore an important buffer against climate change.
Different types of soils have different carbon storage capacities. For example, the few peatland soils in Europe store 20% of all European soil carbon. Wild grasslands and forests also accumulate carbon in their soil, whilst agricultural land mostly releases carbon into the atmosphere, thereby exacerbating the effects climate change. It has been estimated that 15-20 per cent of the carbon dioxide in the atmosphere has been released by traditional ploughing of agricultural land.
In Europe, the largest emissions of carbon dioxide from soil are caused by the land-use change from grasslands to arable land and thereafter to the intensive tillage of that land.
This web of life beneath the ground aerates the soil and allows water to permeate through it. Soils rich in biodiversity purify and store water. As water infiltrates the ground, contaminants including, bacteria and viruses, are absorbed by soil particles. Micro-organisms then get to work making the water both clean and safe. A porous ground channels the water, filtered by the underground biodiversity, to the aquifers. Without a vibrant soil community, the soil becomes poor in structure and water run-off increases, leading to soil erosion and flooding.
Conventional ploughing, up to 30 cm or deeper, releases carbon into the atmosphere also depleting and progressively destroying the micro-organisms which enrich the soil. This eventually leads to crop failure.
Dr John Baker, an internationally renowned expert in soil science and agricultural engineering, states that “the better the quality of the soil, the better the infiltration and water holding capacity at depth and therefore the lower the risk of fertiliser leaching off the land and contaminating water.” He concludes that the most important factor that maintains and preserves soil quality is the biology of the soil. The food stuff for plants, soil fauna and microbes that grow in soil are the soil’s fertility.
There are alternatives to ploughing that would allow soils to regain their natural fertility, also largely preventing carbon leakage whilst significantly improving crop yields. Governments that prioritise well-being, food security and climate change mitigation should promote soil quality and regenerative farming practices.
This article was published in the Senior Times of the Times of Malta on the 23 October 2021
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