Facts about Soil

"Essentially, all life depends upon the soil ... There can be no life without soil and no soil without life; they have evolved together." - Charles E. Kellogg

Soil is defined as the naturally occurring, unconsolidated mineral or organic material at the surface of the earth that is capable of supporting plant growth. Soil is synonymous to the word 'earth', the word from which our planet derives its name. Here are some quick facts about soil.

• Types of Soil: Clay, silt and sand are the three types of soil. Most soils are a blend of all three types. The texture and appearance of soil depends on the content of each of these. Sand is mainly granular and is composed of rock particles and minerals. Clay has fine-grained minerals and high water content. Silt is a granular material derived from rock. It may occur as a deposition in water. Silt is also known as stone-dust.
• Composition of Soil: Soil holds 0.01% of the Earth's water. Soil is a composition of 49% Oxygen, 33% Silicone, 7% Aluminum, 4% Iron, and 2% Carbon. Air and water make up 50% of the soil. Minerals and organic matter make up the rest.
• Formation of Soil: Soil formation is a lengthy process. Soil forms by the process of physical or chemical weathering of rocks. Microorganisms in the soil help in breakdown of organic matter in the soil. Decaying of plants and animals helps in the formation of soil. Earthworms recycle nutrients thus making the soil richer.
• Layers of Soil: The topmost layer of soil is called topsoil. It contains high amounts of humus and microorganisms. Biological activity occurs most in this layer. It is from this layer that plants derive their nutrients. Not much humus is present in the layer below this layer. The process of leaching brings down the minerals from the upper layers to the layers below. The bottom-most layer consists of withered rock.

Some Interesting Facts about Soil

• Soil influences many areas of our lives. It is an integral part of our ecosystem. The composition of the soil in an area has a direct effect on the plant and animal life there.
• It takes more than 500 years to form 2 centimeters of topsoil.
• Ten tons of topsoil spread evenly over one hectare of land comes out to be as thick as one Euro coin.
• A fully functional soil holds 3750 tons of water per hectare, thus reducing the risk of floods. It holds pollutants to a certain extent. Soil stores around 10% of the emissions of carbon dioxide.
• Just one gram of soil contains 5000 to 7000 different species of bacteria. A spoonful of soil can hold a substantial amount of living beings.
• Scientists have found 10,000 types of soil in Europe and about 70,000 types of soil in the United States.
• 75% of the earth's crust is composed of silica and oxygen.
• Soil is a non-renewable natural resource. This should make us think of how much we value this resource. Damage to the soil can disturb nature's balance and prove a threat to life.

It is in this soil that crops grow and we can obtain our food. Many of the antibiotics that stand as remedies for infections, were obtained from microorganisms in the soil. As a matter of fact, agriculture remains to be the only essential industry. Soil in its various forms plays a major role in our lives. In the words of the Greek philosopher, poet Xenophanes, "For all things come from earth, and all things end by becoming earth."