According to the dictionary Priberam, the soil is defined as: “i) the face or surface of the earth; the ground; ii) the material comprising the thin top layer of much of the earth’s land surface, esp. such material as will support the growth of plants; iii) a piece or stretch of ground, a site.” As someone who has studied biology, I consider the soil to be the connective tissue of this planet’s skin. So, I think that the definition of dead soil that I found in the Oxford dictionary should be replaced by one that expresses the idea of a living soil, an ecosystem that is fundamental for life and from which we came, from which we feed ourselves and to which we shall return. The soil may be one of the most precious goods that we will leave to future generations, and it is one of the natural ecosystems that has taken longest to create and develop.
Generally speaking, the soil is created through the weathering and erosion of rocks, initially promoted by rain, changes in temperature and the wind. The lichens and the first plants carried through the air also produced a chemical and physical effect that gradually led to the breakdown and fragmentation of the rocks, while at the same time changing the composition of this soil that was being created, increasing its percentage of organic matter. This humus is an oasis for micro-organisms (such as bacteria), fungi and a variety of animals that feed upon and decompose this material, making the nutrients available that are necessary for an increasingly complex ecosystem. As the soil grows and matures, not only does it become “higher” (deeper), but its composition and biomass reach very high values. One of the hermetic laws, the law of correspondence, states that “as above, so below”, showing that the harmony of opposites and complementarities is a rule of Nature. In this way, the biomass and diversity of organisms below the soil and the biomass that we see growing above this soil are proportional to one another. In a desert, life in the subsoil is diminutive, whereas in a tropical forest it is a “vibrant and interspecific festival”.
Right from the early beginnings of humankind, soils have been considered extremely important, and the anthropogenic uses that are made of the soil affect its productivity (1). Nowadays, we are much more aware that our conventional agricultural practices have destroyed the quality of the soil. Globally, we lose roughly 24 billion tons of soil each year through erosion, as a result of poor management practices (2). Fortunately, the recent (or not so recent) philosophies, cultures and farming practices, such as syntropic agriculture and permaculture, among others, have designed and tested soil regeneration models. At the same time, they have promoted a culture of closer connection with Nature, of which we are also an integral part, and which we are now discovering, like a young man returning home after a series of independent adventures.
The soil has a fundamental role to play in the water, carbon and nutrient cycles, as well as being a fundamental element for our managing to respond to climate change and a powerful ally in our achieving various goals of sustainable development (2). Not only does the soil contain roughly 80% of all “terrestrial” carbon, but this figure also represents more than three times the amount of carbon existing in the atmosphere (3). On the other hand, a mature soil is a genuine sponge when it comes to absorbing water and a filter that that keeps filling up the aquifers, which themselves have a musical dynamic that was heard in the last edition of this magazine. Perhaps the soils also have their own rhythm and melody, needing just some bare feet so that we can take root in this living planet.
Perhaps the root of the humanitarian challenge of this century is in the Soilution… right beneath our feet.
• Neill J. R. & Winiwarter V. Breaking the sod: humankind, history, and soil. Science 304, 1627-1629 (2004);
• Safeguarding our soils. Nat. Commun. 8, 1989 (2017);
• Ontl, T. A. & Schulte, L. A. (2012) Soil Carbon Storage. Nature Education Knowledge 3(10):35.