Soil is a complex substance made of clay, silt and sand. These constituents are made into soil only after the addition of organic material, the dead remains of plants and animals. For millions of years, the earth’s land was barren rocks. Gradually rocks were worn down and pulverized into the fragments that form the skeleton of the soil. Expansion and contraction caused by freezing and defrosting splintered rocks apart. Wind and water eroded the rocks and helped in their movement from place to place. Slow moving glaciers also pushed, scraped and crushed the rocks into finer particles. Then the plants started growing on the rocks themselves. Years after years these plants lived and died. Their remains got added to the masses of rock particles transforming them slowly into the life supporting substance ‘soil’.
The process of conversion of rocks into soil is very slow. The difference in the nature of soil from place to place is due to the difference in the nature of rocks from which they were formed. The plants that grow on the soil, the temperature, humidity determine how fast the organic matter decomposes releasing nutrients into the soil that increase the fertility of the soil.
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