Soil is our home. We breathe the air, we drink the water and we eat the crops, but we live on the soil. And without it, none of the rest would happen. Soil stores twice as much carbon globally as the vegetation above ground, and is a universe of microbial life working with plants to balance the carbon, nitrogen and oxygen levels in the air. When it rains, only a tiny amount of water lands in the rivers, lochs and lakes. Almost all of it lands on the soil, and is filtered and stored, released slowly and steadily back out. Without the soil, we would all be washed out to sea every time it rained heavily.
And our food? Try growing potatoes on bare rock. A lot of the UK’s soft fruit is grown in polytunnels on artificial substrates like coir (which is made from coconut husks), but that is only a fraction of the enormous agricultural output in this country. Around the world, 11 per cent of the total land area is used for agriculture – crops that we eat. Around three times as much is grassland, supporting herbivores – including cows, sheep and other animals that we eat.
Yesterday was designated World Soil Day by the United Nations, an opportunity for soil scientists around the world to celebrate and promote their work and the importance of soil. Around the world, universities, research organisations and soil science societies held events and shared information on Twitter and Facebook.
At the James Hutton Institute, we look at soil a lot. We are looking at ways that soil could store more carbon, to slow down climate change and improve the soil’s ability to carry out a host of functions. Just about everything soil does, it does it better with more organic matter. And organic matter is about 50 per cent carbon. We are studying ways to slow down water in the landscape, to store it in the soil for longer. This will improve water supplies in parts of the world with long dry seasons, and reduce the risks of floods in wet seasons like our own UK winter.
And we are working on crops – a lot of this is plant breeding for different qualities like disease resistance and drought tolerance, but a lot of it is also looking at the effects of the soil on these qualities. How does a farmer maintain soil nitrogen levels to maintain yields, without spending too much on fertiliser and polluting waterways? What can we do to reduce soil erosion, flooding and crop loss by changing how those crops are planted? Which soil microbes increase nutrient availability to crop roots, improving their growth? All of these questions and more need answers to increase our food security, protect the environment and help drive our economy.
Next year, we are beginning a large experiment across three farms in different parts of Scotland in which we will look at the effects of lime on a whole host of soil properties and functions. Lime is important for maintaining the acidity level of soils, which for many reasons has a major impact on how plants grow. Lime also affects the structure of the soil and the chemistry and biology that takes place below the surface so it will also influence how much greenhouse gases are released and the numbers of invertebrates that wild birds feed on. A team of scientists, including ecologists, agronomists, chemists, physicists and biologists will be examining the many effects of lime application. We will be looking at individual effects, but we are also really interested in multifunctionality – the ability of the soil to carry out several important functions at once.
Multifunctionality is an important concept in the soil, and within the James Hutton Institute as well, in how we work. Components interact, each doing something different and contributing to the whole. Synergies are developed, with unexpected results. It is important to make use of these interactions and their potent effects, to understand them and enable them.
Soils are vital. Look at your clothes, your food and the place that you live, and try to see how much of that would be impossible without soil.
Dr Matt Aitkenhead is a soil scientist at the James Hutton Institute, www.hutton.ac.uk