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.

Hilary Benn, Secretary of State for Environment, Food and Rural Affairs, explains the importance of caring for soils.

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

Environment: journeys through a changing world

Other links

BBC Life

British Society for Soil Science

International Union of Soil Sciences

European Union Soil Thematic Strategy

About the author

Dr Yoseph Araya is a plant ecologist and associate lecturer at the Open University. He works on the biology and conservation of South African fynbos vegetation. Environmental education and the role of the public in research is one of his key interests.

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Conferences take a lot out of you. No, really, they do. It’s hard work concentrating so hard for so long and I’m beginning to find my mind wandering more often in the talks. Which usually means I miss some critical piece of information and then I’m lost. Or, more interestingly, I enter that odd, semi-conscious state in which my brain is partly asleep but also concentrating hard and the physical things around me momentarily take on unexpected properties. I’m beginning to wonder if the likes of Hunter S. Thompson and William Burroughs spent a lot of time going to five-day conferences. When I manage to keep my mind on the task in hand, today’s talks are very interesting (even without the perceptual enhancement through sleep-deprivation). John Thompson from the University of California, Santa Cruz, gave this morning’s plenary lecture and a cracking tour de force it was too, as you can hear from my interview with him. He took us through the current thinking on how evolution acts not directly on organisms themselves but on the interactions between them. Species eat other species or otherwise depend on each other (where would insect-pollinated flowers be without their co-evolved partners-in-fertilisation?) and evolution can make its presence felt here. But don’t take my word for it; listen to John Thompson himself – he tells it much better.

After John’s talk I was looking forward to the session on Early Evolution, not least because my colleague from Sussex, Joel Peck, was speaking. But since the acoustics in the lecture theatre made the talks muffled and indistinct, I reluctantly decided to go elsewhere in search of a session that was interesting and easy to hear. I don’t think I was in much of a receptive state though. I feel sorry for anyone scheduled to speak on the last day of a long conference: you have your talk hanging over you the entire time; nobody hears what you’ve got to say until it’s too late to talk about it over a beer or three; and no matter how interesting your material, the audience will struggle to take it in simply because the previous few days are starting to make their physical influence felt.

And that - other than the final social event in the form of the conference ‘banquet’ - was it. If there’s a general impression I’m taking away from the conference it’s how willing evolutionary biologists currently are to re-examine previously rejected ideas. Take the Levels of Selection issue these blogs started with. Rather than rejecting ideas of group selection outright, a growing number of biologists seem comfortable with the suggestion that such a maligned idea might not apply under certain, particular conditions after all. Or the concept, discussed by Richard Palmer in his interview, that the genome might somehow be able to hijack variation that is solely due to the environment (such as the handedness of lobsters) and impose a genetic basis upon it (such as handedness of fiddler crabs). Previously this might have been instantly dismissed as Lamarckianism (and probably still is by many), but that doesn’t stop some asking if, after all, it might not occasionally happen in some modified form and if so, wouldn’t it be something if we could find out how?

Investigating the limits of ideas is exactly what science and scientists ought to be doing. It may be that the conditions under which a process works turn out to be too restrictive for it ever to occur. So be it. Or those conditions may be restrictive but may occur occasionally. So be it: as mentioned in the discussion on The Origins of Life on the Darwin Forum, rare events in the history of life have sometimes been exceptionally important. Or it may be that new or resurrected ideas are very necessary to gain a fuller understanding of evolution. So be that too. The advances over the last few decades have changed a lot of things in biology and caused us to question what we have taken for granted. That can only be a good thing. Question, experiment and then accept what the results of those experiments tell you – there’s the rational recipe.

Maybe I was lucky with the people I talked to and the sessions I attended - other experiences of the European Society for Evolutionary Biology conference may well be different. Leaving it though, I feel encouraged and completely unable to concentrate on another talk for a day or two.

About the author

Paul Craze is an evolutionary ecologist based at the Universities of Bristol and Sussex. He's an invited contributor to our Darwin and Evolution forum and contributes to The Open University's Evolution course. Paul also performs in an unusual band with some editors of Nature.

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Once upon a time I did some molecular biology. I wasn’t very good at it. I guess some people have the knack of working meticulously and imaginatively with tiny amounts of chemicals and some don’t. I don’t. Plus, I wanted to collect my data in the open air and the opportunities for al fresco molecular biology are a bit limited to say the least. The aim of my failed attempt at molecular biology was to better understand ‘transposable elements’ and what they mean for evolution and, despite my sometimes spectacular inability to discover anything about the little buggers at the laboratory bench, I’ve kept up an interest in them.

So I was very pleased to see that the plenary lecture of Day Four of the conference was by Cristina Vieira, from the University of Lyon in France, on Transposable Elements and Genome Evolution. You can hear a lot more about them in the interview I did with Cristina after her lecture but just to fill in a bit of the background: transposable elements are part of the so-called ‘junk’ DNA that’s been found to occupy huge parts of the genomes of many organisms. In fact, 50% or more of the human genome turns out to be transposable elements or bits of transposable elements. It’s not completely clear where they come from but many seem to be the result of viruses that have found their way into the genome and have taken up permanent residence. All a transposable element does is jump from one place in the genome to another, sometimes by cutting itself out and reinserting, or making a copy of itself and having the copy insert somewhere else, depending on which type of transposable element it is - hence their nickname of ‘jumping genes’.

Of course, having these things jumping around your genome, inserting themselves all over the place like the ultimate molecular parasite, is going to cause a lot of disruption and mutation. That’s why most species have evolved ways of stopping transposable elements from moving. These mechanisms tend to involve changing the scaffolding of the DNA (not the sequence itself) so that it shuts down; something that can change the genome even further. So, as you can hear directly from Cristina, both the transposable elements and the counter attacks a body’s cells mount against them can generate very large amounts of variation. And, since it’s variation that evolution works on, that makes them interesting for evolutionary biologists.

About the author

Paul Craze is an evolutionary ecologist based at the Universities of Bristol and Sussex. He's an invited contributor to our Darwin and Evolution forum and contributes to The Open University's Evolution course. Paul also performs in an unusual band with some editors of Nature.

Subscribe to Paul Craze's posts