Technical & Legislative Update

Dishing the dirt – why soil matters

On 25 September 2015, the 193 countries of the United Nations General Assembly adopted the 2030 Development Agenda entitled "Transforming our world: the 2030 Agenda for Sustainable Development". Outlined in the agenda were a set of 17 Sustainable Development Goals.

The Sustainable Development Goals (SDGs) are designed to be a "blueprint to achieve a better and more sustainable future for all" and cover such things as poverty, hunger, health and well-being, clean water and sanitation, climate action and responsible consumption and production. But what isn’t widely known is that one of earth's most valuable, yet overlooked resources specifically relates to four out of those 17 targets. That resource is soil.

What is soil and why is it so important?

Soil is a mixture of minerals from rocks, organic matter derived from decaying plant and animal material, air and water. It also contains tiny living creatures such as insects, earthworms, bacteria and fungi. In fact, it is estimated that 1 gram of soil contains approximately 4,000 - 50,000 species of micro-organisms!

It also contains more carbon than the atmosphere and all the world’s forests put together and the more fertile it is, the more carbon it holds, meaning it is one of our key defences against climate change. But soil can only capture carbon when it has a good amount of organic matter.

About 95% of our food comes from the soil and the quality of the soil influences the quality of food, especially in relation to the amount of important trace elements, such as selenium and zinc, and arguably

also in relation to taste. So, as we are a nation of food lovers, you can start to see why soil is just as important as the air we breathe and the water we drink.

However, this natural resource we rely on so heavily is eroding at an alarming rate. Astonishingly, it is thought the world is losing the equivalent of 30 football pitches of soil every minute! Furthermore, according to the United Nations Food and Agriculture Organisation (UN FAO) one third of the world’s soil is now moderately to highly degraded.

Where does the problem lie and how do we fix it?

Unfortunately, although modern farming practices and the use of synthetic fertilisers have produced good harvests, this has affected the long-term health of our soil. Farms and agricultural machinery have got bigger, areas of land have been overgrazed and we have lost a large number of hedgerows and trees, meaning increased exposure to water and wind erosion. Cumulatively, this has resulted in more organic matter being lost from the soil than has been returned.

A solution to the problem may lie with the use of ‘cover crops’. Generations ago, farmers would use crops such as rye grasses, oats and radishes to help to slow soil erosion and loss of nutrients

by keeping roots in the ground all year long, thus increasing the amount of organic matter in the soil, enhancing water availability, smothering weeds and reducing greenhouse gases.

Ploughing also disrupts life in the soil and because of this some farmers have shifted to ‘no-till farming’ (also known as zero tillage or direct drilling). This is an agricultural technique for growing crops or pasture without disturbing the soil through tillage. No-till farming decreases the amount of soil erosion tillage causes in certain soils, especially in sandy and dry soils on sloping terrain. It also occasionally uses cover crops. Of course, cover crops then need to be killed so the newly planted crops can get enough light, water and nutrients.

Target 2.4 of the SDGs also suggests that, wherever possible, practices such as farming following the direction of the slope which can cause soil erosion should be substituted with sustainable practices such as terracing or construction of grass strips following the elevation contour lines of the land. Whilst target 15.3 talks about increasing and maintaining the organic matter of soil by promoting crop rotation and diversification.

Few of us probably think about soil when we are doing our weekly shop, but the reality is that if changes aren’t made, food production will decline and we will be unable to meet the rising needs of our growing population. In fact, at the current rate of degradation, it is estimated we only have enough soil left globally to provide food for another 60 years, or in UK terms, another 100 harvests.

We need soils to produce higher yields in the years to come and therefore urgent action is needed to move to a more sustainable soil management programme which will generate benefits for all including:

Food security and nutrition

Increased biodiversity

Adaptation to climate change

Economic growth….and even prosperity

Denise Rion, Head of Technical

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