The soils surrounding the village where I live in the north west of England have abundant fertility. They mostly formed in well-drained, clay-rich debris left behind by glaciers that retreated from the area some ten thousand years ago, and they now support lush, productive pasture, semi-natural grassland and woodland. Although the pastures are managed more intensively than they were in the past, most of them are well drained, and receive regular dressings of manure along with moderate fertiliser, and are regularly limed, which keeps the land productive and the soil in good health.
Sadly, the same can’t be said about soils in most parts of the world. The United Nations recently published a report on the status of the world’s soils with the headline message that the majority of soils are in a poor state and urgent action is needed to redress this. But why would the United Nations concern itself with soil, which, for most, is largely out of sight and mind? Put simply, healthy soils are of vital importance for human life, and we are not paying enough attention to their health.
Soil is essential for the production of healthy vegetables and crops, but this is just one of its vital roles: it plays a critical part in buffering climate change, and in storing and filtering the water we drink. Soils are home to an incredible diversity of organisms that breakdown and recycle dead plant remains and organic manures, and drive the biogeochemical cycles on which the functioning of the Earth depends. Soil plays a major, but mostly forgotten role in towns and cities: it helps excess water drain away after storms; it helps to regulate the heat and quality of urban air; it binds and breaks down the pollutants that industry yields; and it provides a foundation on which city dwellers grow their vegetables and flowers, and play their sports.
The message is clear: the earth beneath our feet matters.
So why are so many soils of poor health? The simple fact is that soils take thousands of years to form, but they can be degraded within a matter of years or decades if managed inappropriately. At the heart of a fertile soil are natural processes of organic matter supply and recycling, and the efficient supply of nutrients to plants at critical times of growth; both are driven by the rich diversity of microbial and animal life that lives in soil. The maintenance of good soil structure, which allows roots to exploit the soil for water and nutrients, and for water and gases to move freely through the soil profile, is also central to soil health. Whatever the cause, if a soil is worked too hard for too long, and the natural processes that underpin its fertility are not maintained and replenished, its health will decline.
Unfortunately, examples of soil neglect are all too common. In some parts of the world, land is cultivated year after year without rest, robbing the soil of its organic matter and causing rapid declines in soil health. Unstable hill slopes are being deforested leaving soil bare and vulnerable to erosion, and in dry parts of the world, salinization (or salt build-up at the surface soil) is causing havoc, with soils being left barren and unable to support crops. Catastrophic soil erosion is also being caused by overgrazing of natural grasslands, desertification, and abandonment of traditional farming practices such as leaving land fallow to restore soil fertility. And as towns and cities expand, vast areas of fertile agricultural land are being engulfed by asphalt and concrete, effectively suffocating the soil. As if things couldn’t get worse, soil degradation is being exacerbated by climate change, and surveys report a growing number of endangered soils and several that have already gone extinct. In sum, soil degradation is widespread, and just as humans are causing the extinction of plant and animal species, they also are causing the extinction of soils.
Fortunately, not all soils are of poor health; on the contrary, the Earth is rich in natural soil variation, and many agricultural soils are well managed and of good health, and able to support healthy crops. Also, soils can be remarkably resilient, and while past soil damage can leave an imprint for many centuries, recovery can be relatively fast if treated properly. That said, there is little scope for complacency, and as the United Nations report concludes, action to save our soils is urgently needed.
So what can be done to put a halt to soil degradation and enhance the health of soils?
First, there is a need for greater awareness. Some people already appreciate the value of soil, but to be blunt, most don’t. There is therefore a fundamental need for educational programmes for all members of society to build knowledge of the importance of soil.
Second, while history can tell us much about how best to manage soils to maintain their health, scientific understanding needs to advance. But this needs to be done in a holistic way, integrating new knowledge on the physical, chemical and biological behaviour of soils into wider understanding of how to manage soils for growing food, protecting clean water, and mitigating climate change.
Third, in order to be of use, this growing scientific understanding needs to be translated into practice; soil issues need to be embedded in all future decisions on the use of land, whether that be for farming, forestry, flood prevention, the design of cities, industrial development, or the protection of land to conserve biodiversity.
Finally, and perhaps most importantly, attitudes to soil need to change. Soil needs to be considered as an investment to be protected and cared for, and as part of the support network for human life. It is a precious resource. And if it is not treated with respect, it will be gone for good. As many have said before, civilization has its roots in the soil, and without soil there will be no future life.
Featured image credit: Earth soil campaign by AlexSartori. Public domain via Pixabay.