Ed Golson Outdoor Education

Soil Formation

The formation of soil takes a very long time, about 1,000 years or more. It all starts with bare rocks. Over time, wind, rain, and other physical processes cause the rock to break down and erode into smaller pieces. Water plays a big part in the physical weathering of the rocks. Liquid water gets into tiny pours of the rock. When it gets cold, the water freezes and expands, which forces the holes to get bigger. Eventually, the rock may even split off entirely due to the freezing of water.

Once the rock starts to break down, chemical processes help speed up the wearing away, or erosion, of the rock. Hardy lichens and simple plants such as mosses can grow on nearly bare rock. The roots of these plants are very persistent and are capable of releasing chemicals that will soften the rock. Over time, the action of these roots will cause the rock to break down, become smaller, even faster. As these plants die, they add their organic material to the pieces of rock that have worn away and create soil.

Eventually, enough rock will have worn away and enough organic material will have piled up for larger and more complex plants to take over. They speed up the process even move with their larger root systems breaking the rock apart even further. Hungry animals will soon come to the area, attracted by the plants. As they die, they will add their own organic material to the mix, giving the new soil many valuable nutrients.

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