Digging deep to leave a legacy of good soil

Soils carry a history, often thousands of years long, within them. Picture: GettySoils carry a history, often thousands of years long, within them. Picture: Getty
Soils carry a history, often thousands of years long, within them. Picture: Getty
We need to ensure a stable source of food, says Matt Aitkenhead

SOIL is the memory of the land. Sounds odd or a little New Age? Let me explain. Soils, like people, are the product of both their genetic material and their environment. For people, the genetic material is our DNA. For soil, it is the rock, sediment or other geological material that soil is built up from. The environment includes a number of factors, such as climate, flora and fauna and topography that produce the soil’s character over time.

Soils, therefore, carry a history, often thousands of years long, within them and this history can be read and understood by those with the skills and experience to do so. So when we say that soil is the memory of the land it is because all of the things that have happened to the land over time are recorded, minutely or in broad strokes, within the soil. Does it have a deep layer of decomposing organic matter? Then it probably formed in a wet environment. A layer of ash embedded at depth? Then possibly a forest or moorland fire. A high proportion of a particular type of clay? This tells us about the kind of parent material and possible erosion in the area.

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The UN International Year of Soils started on 5 December (World Soil Day). This is an opportunity to celebrate the importance of soils to life on Earth, and to demonstrate the numerous large and small ways in which soil impacts on our daily activities. Around the world, many organisations involved with soil teaching or research will be showcasing their work in this area, and linking ongoing activities to the soil that underpins them. Governments will also be doing so. The James Hutton Institute is no exception in this, and has a full and varied calendar of events planned.

It’s not enough to describe myself as a soil scientist, I always feel the need to explain which area of soil research I work in. The reason for this is the complexity of the subject – it encompasses many of the core scientific disciplines like chemistry, physics and biology, as well as many others such as geography, economics and sociology. How exactly do we value soil? Additionally soils are studied at scales from the molecular up to the national and even international. All of this makes the study of soil a fiendishly, sometimes perversely complex subject, but we soil scientists do love a challenge. And it is organisations whose staff have expertise across this wide range of subjects that can tackle the subject most effectively.

The James Hutton Institute is one of the few institutions with this capacity in expertise in the world, and certainly in the UK. To demonstrate this capacity, we are using the International Year of Soils as an excuse to demonstrate the breadth and depth of our soils research. We are also eager to show how important it is to link this research to policy, industry and wider society, to ensure that it has the greatest possible benefit for society and the environment.

Much has been made in the past two decades of the concept of sustainable development. I always think of this as having a bank account and living off the interest without taking out the capital. Within the environment, soil can be thought of as part of this capital. The interest is the services that are provided (food, fuel, water, support for biodiversity and crop pollination etc). You can take a big lump sum out and use it for something, but the remainder in the account gives you less interest. It’s the same with soil – the more damage we do from over- or inappropriate use, the less we can expect back in the long term. The problem is that right now, the interest we’re getting from the bank account isn’t enough. We keep dipping into the capital in order to keep our economies strong. Can Europe afford to build a new Berlin every year on good quality agricultural land?

At the James Hutton Institute we are looking for ways to secure our soils for the future. Only in this way can we ensure stability in our food and water supply, biodiversity, energy supply and our climate. We must ensure that the memory the soil will have of us in 2015 is a good one – future generations will not forgive us if we fail.

As two esteemed US soil science colleagues, John Doran and Timothy Parkin, expressed it in 1994, the thin layer of soil covering the Earth’s surface truly represents the difference between survival and extinction for life on our planet.

Dr Matt Aitkenhead is a soils modeller at the James Hutton Institute and worked on this article with Dr Helaina Black and Willie Towers. For more information see www.hutton.ac.uk/soils