Formation of Soil
Now that we have covered 2 of the 3 natural resources available to us, let’s look at the third natural resource, that is soil. And we will start looking at how the soil is formed and what do we actually call as a soil. Let’s first look at soil formation. And when we are talking about the soil formation, it actually involves the breakdown of rocks and the rock cycle and understanding how we actually get the final soil, from where all the plants actually grow. Soil is a mix of geologic and organic compounds. That is, it is a mix of rocks, which powdered down, plus the dead and decaying organic compounds along with a team of all other living creatures and organisms, and if you have actually observed or seen that things don’t really grow well in sand. And pure sand is just rock. And for plants to grow, you will need a mix of organic matter as well. And that’s what you really do to sand to convert it into soil. You actually mix fertilizers, or manures or compost, so that you get the organic components. So the soil has got 2 parts. It has got a part which is broken down rock and it also has organic matter. When you basically mix both of them, you form soil. Just like the hydro-cycle or the water-cycle that we spoke about, soils also go through a cycle. Or it also has a life-cycle of its own. They too- just like human life- are born, they mature and become of age and in some cases they may even die or disappear or get buried deep underground. So soil formation starts by disintegrating the rocks under the influence of climate. Rainwater will dissolve rock elements, temperature fluctuation will cause differential expansion and contraction of the rock forming crystals, and the freezing and thawing of the water captured inside the rocks will widen existing gaps or cracks inside the rocks.
At first, the lichens start to grow. While growing these lichens release certain substances that cause the surface of the rock to powder down and form a thin layer of soil. Other small plants, like moss, are now able to grow on this particular surface. Now that they cause the rock to further break-up and become smaller and smaller fragments. These plants will settle and the roots will further loosen the rock. Moreover, decaying plant debris will produce organic acids which further attack the rock. Organic matter will start to accumulate and will be mixed with minerals provided by the rocks to finally form the soil. At this stage the soil is born.