Just like water, air and other natural elements, the soil may be considered a resource; it is, however, a non-renewable resource (FAO, 2015; APPA, 2012) – or a potentially renewable one if it is considered from a geological point of view (Fedrizzi, 2011) – if one thinks that its formation times are much longer when compared to the length of human life: a metre of soil takes from 10,000 to 50,000 years to form! Erosion is a natural physical process responsible for the continuous modelling of the Earth’s surface and also determines the removal of material from the surface of the soil. Very often, however, man can speed up the natural process of soil erosion, causing its increasingly rapid destruction compared to its natural formation times. Intensive agriculture is among the leading causes of soil depletion; the use of synthetic fertilizers and pesticides, while on the one hand increasing agricultural production, on the other deplete the soil, accelerating its erosion processes. The need to find new farmland has, over time, also led to cutting down vast portions of woodland; deforestation is another major danger for the soil, which after a few years becomes arid, remaining permanently unproductive. Desertification represents an extreme consequence of the loss of soil productivity and is accelerated by climate change.
But what strategies can be adopted to combat accelerated soil erosion and desertification? Use “coverage” crops during periods when the soil would be devoid of vegetation cover; reduce the steepness of slopes by terracing; eliminate excess water from the soil through drainage works (i.e. drainage trenches); build windbreaks, plant trees arranged in such a way as to reduce wind speed and thus its erosion action; recover certain elements of traditional crops (crop rotation, use of natural fertilizers) are just some of the strategies to be implemented to counter the erosion action of weathering and soil depletion.
- Fedrizzi, 2011. Scienze della Terra. Minerva Scuola.
- Calvino, 2009. Il nuovo Explorer. Lezioni e immagini di Scienze della Terra. Linxedizioni.
- Agenzia Provinciale per la Protezione dell’Ambiente (APPA). Provincia autonoma di Trento, 2012. Rapporto sullo stato dell’ambiente 2012. Suolo e bonifiche.
- FAO, 2015. Anno internazionale dei suoli 2015