Transcript of Soil
Weathering, Erosion, and Soil Formation Weathering- mechanical and chemical processes that cause exposed rock to break up physically and chemically This statue has been exposed to acid rain for quite some time. The acid rain has caused the wearing away of facial details, and caused many indentations. Chemical Weathering Mechanical Weathering This rock has been affected by chemical weathering. When these small indentions fill with carbonic acid, they become deeper and larger. Since the holes capture the rain/carbonic acid, they speed up the process because the rock is exposed for a longer period. Sometimes chemical weathering can change the color of certain rocks. This is because the chemicals in the rock are being changed. In this case the red color is caused by the iron oxide formation on the rock. In this photo we can see that the tree has grown its roots into the rock. When the roots find a small crack and continue to grow in it, they separate the two sides. The roots could almost be descibed as a wedge. There is often severe weathering at the coast. Here the waves are doing the weathering. The waves crashing against the rock break it up, and form small particles. In this photo there are many separate rocks. These most likely were just a few individual rocks. Trees, ice, and wind might have caused this breakup of rock. Positives The process of weathering allows the breakdown of large rocks into smaller rocks. These smaller rocks (sand and pebbles), make up a portion of many types of soils. In other words, weathering helps in the formation of soils. Negatives By breaking down rocks, larger areas of a rock are exposed. With a greater surface area, the rocks are more prone to chemical weathering. Thus when stones have more surface area they break down faster. When our stone buildings and ancient artifacts experience weathering, it can be disasterous. Not only does it make the structure hard to repair, but it also makes the structure unstable. When it comes to driving and other outside activities, weathering can be dangerous. In areas where there are rocks, cliffs, or slopes, there is the chance of falling rock. When ice freezes it can separate rocks and cause them to fall. Erosion-The process by which the Earth's surface is worn away by wind, water, glaciers, and gravity. Wind Water Glaciers Gravity This type of erosion can occur when areas of land have no vegetation. With no vegetation, the soil becomes dry and light. Wind picks up and blows away the small particles. Wind erosion mostly takes place on the topsoil. Doing improper farming methods may result in wind erosion, and might cost the grower millions. This type of erosion is mainly caused by rain and or flooding. As seen in the picture to the right, a stream has eroded the road. This stream is not there all the time. When large amounts of water travel in a often dry area , it can cause gullies like in the picture above. This type of erosion is probably the least common of the four. It only occurs in colder climates where glaciers are present. As the glacier travels by mountains, it slowly breaks away the stone. This makes a gravel like area, or a area of smooth rocks. This type of erosion could happen slowly or suddenly. On steep slopes, rocks can move over many years, and become lower than what they were before. Some articles refer to landslides as gravitational. Positives Negatives Whenever soils are eroded, they travel into streams. These minerals are carried into flood plains, and make rich areas to grow food.Full transcript
When surfaces are eroded it can cause the land to be reshaped, and sometimes less dangerous than it was before. when farmland is eroded it can cost the farmers millions, and cause a problem for the ecosystem around the area.
Rapid soil erosion can be very dangerous. Most common rapid erosions are mud or rock slides. These can be deadly for people in the path of the slide. Soil Formation Soil Classification Types of Soil Mountain Soil- This soil commonly has more rock than that of piedmont or coastal areas, and is found in mountainous regions. Desert Soil- The main difference of this soil type, is that it is lacking a good fertile top soil. This area is also quite dry. Rainforest Soil- This soil type is light brown, and this is due to the lack of large amounts of organic matter. When it rains, much of the organic matter is washed away. Thus,the rainforest has a thin layer of topsoil. Rainforest When organic matter accumulates on the ground, it packs down and begins to decay. Many microrganisms and fungi cause this material to decay. This decay is some of the fastest in the world, however with frequent rain most of this organic matter is washed away. Grassland Grassland soils are formed when dead animals and plants decay. Plants and animals do not decay here as fast as they do in the rainforest. In grasslands there is often the chance of fires. These fires burn up plant material and add a layer of rich organic material on top.