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Soil: Introduction

Soil: Introduction

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What natural agents can break down rock into smaller pieces?

Soil: Introduction

Would you believe that one of the most important natural resources on the planet is right under your feet? It’s the loose material that covers the ground - the soil! Soil is more valuable than you might think - without soil, life on land could hardly exist! What is soil actually made of? Basically, it’s rock.

First of all, water and wind grind the rock down into tiny pieces. This is called weathering and is the first step in the formation of soil. Depending on how big or small these tiny rock particles are, we group soils into different categories. Soil made of larger pieces of rock is called sand. These grains of sand feel rough and coarse.

Soil made of slightly smaller grains is called silt. Silt feels smooth and floury. When soil has very small particles, it is called clay. Clay feels hard when dry and sticky when wet. Most often, however, soil is a mixture of sand, silt, and clay.

In the spaces between the grains there is water and air. Different types of soil can hold different amounts of water and air. Sand grains are big, so the spaces between them are big too. Because of that, sand holds a lot of air, and water drains through it very quickly. In comparison, tiny clay particles are packed tightly together and can hold a lot of water but not much air.

Soil plays a very important role in the environment. Air and water in the soil allow organisms to live there. Such as bacteria, fungi, plants, insects, or small rodents. With time, the organisms living in the soil die and decompose. Then, their organic remains mix with inorganic particles of rock and minerals.

These decaying remains form humus, which enriches the soil with nutrients. Plants need nutrients to grow. Soil also filters water and it even helps to regulate the amount of carbon dioxide in the air! Soil is useful for people in many ways as well. One way people use soil is to grow plants for food.

Soil is a very valuable resource in farming. It provides nutrients, water, and support for the roots of plants. Soil can also be used as a building material: to manufacture bricks and concrete, or even build houses! Specific types of soil have their special uses, for example sand is used to make glass; while ceramic products such as tiles, or pots, are made of clay. Clay can even be added to beauty products such as face masks!

Soil is a mixture of inorganic rock particles and organic remains of dead organisms. Soil creates perfect conditions for many organisms to live. Soil is a precious natural resource in farming, but it can also be used in other ways. However, many human activities can reduce the quality of soil. Since it can take hundreds of years for soil to form, we need to use it carefully and responsibly.