Human beings derive most of their food from plants nurtured by soil. It then follows that, to be healthy and have the energy to to do what we aspire to in our short lives, we need to eat good food, for which we need to maintain good soil health.
Because of the current agricultural practices, compaction, deforestation and mining leading to erosion and imbalance in the natural cycles, our soil continues to degrade. Decreasing soil fertility leads to famines, poor nutrition in food and an overall stress on the system to feed the existing human population. This stress to meet the growing food requirement is dealt with chemically synthesised infusions and fertilisers, which further deplete the nature of soil and its ability to regenerate itself.
There are several ways of looking at soil. It not only provides us food, it is the earth beneath our feet. Soil forms the skin of our planet, a thin layer (pedosphere), providing a medium of growth for higher plants and a micro-biome. It is estimated that an inch of top soil takes tens of thousands of years to form. The formation (pedogenesis) occurs as a result of interactions between the geosphere, biosphere, hydrosphere and atmosphere. Scientists base it on five important factors: time, parent material, biotic factors (plants, animals, micro-organisms), topography and climate.
(This means that if all these five factors are same in two different places, the soil formed will be the same.)
Rock material is weathered into smaller and smaller pieces over time by the effects of climate (temperature, wind, rain, sun), plants and animals, chemical reactions and erosion, forming layers or soil horizons.
Most soils exhibit three horizons –
the dark topsoil or A horizon,
this is the part of the soil that is alive and supports the growth of several micro/macro organisms, nurtures plants, gives us food and cycle energy by allowing decomposition. The horizon’s depth affects the growth of roots and their nutrients or water supply. The deeper the A and B horizons of the soil, the more water it can store and the better plants will grow. Shallow sandy soils are most suited to grazing and growing trees.
the more clayey subsoil or B horizon,
this is the part of the soil that we have used since ages for craft,
and underlying weathering rock material or C horizon.
These horizons taken together in a specific place form the soil profile, which is basically the accumulation of the information of the topography, climate and existence of the place through time. The story of the soil reveals the formation of the area.
Soil materials, irrespective of their type and origin, are also in a continuous motion and flow within the natural landscape because of the action of water (alluvial soils), gravity (colluvial soils) and wind (aeolian soils). For example, heavy rains erode soils from the hills and deposit it in lower areas, forming deep alluvial soils. The soils left on steep hills are usually shallower.
Soil forms an important part of the flow of energy in nature and its purpose is much more than producing food for us. It’s desirability for building, healing, craft are only some among the many ways humans engage with soil.