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There’s no hiding the impact of human life on the planet and for those in the know, the same thing goes for human impact on the soil. The way we use the land is a strong control on the ability of soils to sustain plant and animal life and the maintenance and development of those soil resources. Take the well-known issue of desertification for example: some soils are high in sand and low in organic matter and therefore don’t naturally bind together very well (organic matter acts a bit like glue for the mineral soil particles). Combine this with large trampling pressure from livestock and people and/or constant cropping whereby no residues are returned to the land and the outcome is loose soils, easily carried by air or water, leaving behind infertile bare rock.

A different example arises from my memories of my PhD studies on peatland environments. How we manage peatlands has a powerful influence on the capabilities of carbon storage, peat accumulation and fertility. Peatlands might be drained or excavated for a variety of reasons including agricultural, forestry, horticultural or fuel demands. When we drain a peatland, we allow respiring organisms to use the carbon locked away in that soil as ‘food’ and they release it as carbon dioxide. When we excavate a peatland we take away the ability of the landscape to create more peat (and therefore locking away more carbon). Striking a balance between the use of peatlands for exploitation and conservation is important for the future of these landscapes.

Soil management is particularly important for farmers, who are the only group of people (save perhaps very keen gardeners) that might be said to have an in-depth relationship with the soil, requiring substantial knowledge of the resource available on their land. Farmers on the whole are aware that it is a foolish move to disrespect the soil by overworking it. Sometimes the pressures of making a living from the land and the high reliance on factors outside of the control of the farmer (i.e. the weather, market prices, disease) can lead to a soil becoming more taxed than it can handle. This is particularly the case for intensified farms, where the land is in continual use and overworked soils are compensated with fertilisers. Fertilisers usually focus on the key nutrients (nitrogen, phosphorous, potassium) and exclude other important nutrients that are also required by plants (to a lesser degree than the aforementioned ‘macronutrients’). So follows a reduction in crop yield, for reasons that seem inexplicable without tests to confirm what is missing. In light of our understanding of the soil systems, few realise the careful balancing act that farmers must contend with when managing their soils. In the UK, there are a substantial range of consultancy business and governmental advice organisations that focus on providing a service to the farmer to help them to understand the impact they have on their soils and how to preserve them for future harvests.

Finally, what about the soils in the cities? We may pave over the land but below the tarmac, the soil is still there. In city parks, soils provide a valuable service; they feed plants that help to soak up some of the bustling city emissions (and give city residents a cool and pleasant space for recreation). These important functions are often termed ‘ecosystem services’ and even in our urban centres, they provide utility that has an influence on the surrounding environment and human quality of life. In the next article, I will focus on these ecosystem services in urban environments and talk a bit more about what makes the city different from the countryside in terms of understanding our ground to sky interface.

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