Healthy Soils for a Healthy Life is the motto of the UN International Year of Soils which aims to “increase awareness and understanding of the importance of soil for food security and essential ecosystem functions.” As explained on the campaign’s website, “soil is the thin layer of material on the Earth’s surface. It is a natural resource consisting of weathered and organic materials, air and water. As it is the medium in which plants establish themselves and grow, the most widely recognized function of soil is its support for food production. Soil provides nutrients and water that are absorbed through plant roots and contribute to the regulation of water and atmospheric gases and therefore play an important role in climate regulation.”
Soil therefore matters most where is is near human population, which at the same time puts soils under extreme pressure in these areas. Soil types not least determine where humans used to settle when they gave up their nomadic lifestyles and started becoming more stationary as farmers. Nowadays, some of the most fertile soils are found in the most densely populated spaces on the planet, which is shown in the following map. The map shows the major soil types classified in the FAO/UNESCO Soil Map of the World reprojected on a gridded population cartogram where a grid is resized to give every person living within a grid cell an equal amount of space (reducing the map in those spaces most where there are fewest people):

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