Life, a recent BBC nature documentary series, is a showcase of the diversity of the natural world and the extraordinary behaviour of living things. It seems that nature never fails to amaze the curious investigator; be it far, close or even underfoot.
“We know more about the movement of celestial bodies than about the soil underfoot.” - Leonardo da Vinci.
Yes, underfoot is the soil I want to talk about, which one of my professors fondly refers to as The Book of Nature. He would say, “Open The Book of Nature and read… here and there a chapter might be incomplete or you may not understand, but you can always learn about the past, the present and the future.” Indeed, my limited reading has found a lot of interesting chapters…
What is soil?
Technically defined, soil is a "natural body comprised of solids (minerals and organic matter), liquid, and gases that occurs on the land surface. It is characterized by distinguishable horizons and or the ability to support rooted plants in a natural environment".
In a much more ecological way, it is the basic structure that supports life’s primary producers, i.e. plants. It does this as a result of its unique capability to act as a reservoir of nutrients/water and then to supply those intermittently to the plants - very much like a prudent bank.
This is not the soil’s only role; it also acts as a foundation for infrastructure and as a cornerstone in the health of ecosystems, for example, by locking pollutants and harbouring ultimate decomposers. As such, it is considered as one of the three most vital natural resources, alongside air and water.
Why care for soils?
Knowledge of the soil's physical, chemical and biological make-up is important for various disciplines. For example, nutrient levels are important for crop production, soil shear strength is crucial for engineering construction, and its structure could also be a deciding factor for football pitches! It also has more exotic uses, such as a beauty accessory (see the intricate hair-styling of the Hamer of Ethiopia, for instance).
In addition to their functional roles, soils have been part of our life and culture in many ways. A recent book, Soil and Culture by Edward R. Landa and Christian Feller, pays tribute to their impact from visual arts to religion and from archaeology to disease and warfare, and as a further example, many states in the U.S. have a specific soil that is legislatively established as a ‘state soil’, just like a state bird or flower.
What is the status of soils today?
Like most of earth’s resources, soils in all parts of the world are under threat. From the physical problem of compaction to erosion, and from salinity to pollution, are increasingly degrading our soils, with negative effects on ecosystems, economy and human health. In addition, global warming threatens to release carbon trapped in soil's organic matter, exacerbating climate change and having grave consequences for life on earth.
What's being done?
As the concern on soils has come to the forefront of public awareness, national and international bodies are moving towards legislation and action. For example, the UK government’s Department for Environment, Food and Rural Affairs (DEFRA) recently published a revised strategy on soils.
EDITOR'S NOTE: This article was originally published in 2009, and contained a video of Hilary Benn - in his then role as Enivronment Secretary - talking about soil quality. Following the change of govenrmnent in 2010, this video was removed from YouTube and a new document, Safeguarding our soils: A strategy for England, was published by the coalition government.
Take it further
Educate yourself and others with the Soil Science Educational Resource.
Join surveys, for example, the OPAL national soil and earthworm survey.
Support those who are working to improve soils situation, such as the Soil Association.
Open University courses
Neighbourhood nature [Free version]