Soil formation and erosion are important topics in AP Environmental Science (APES), as they relate to the Earth’s systems and resources. Here is a brief summary of soil formation and erosion in about 1000 words:
oil formation starts with parent material, which is the rock or mineral matter that is the original source of the soil. Over time, weathering occurs and the parent material is broken down into smaller and smaller particles. Weathering can be physical, chemical, or biological. Physical weathering is the mechanical breakdown of rocks by water, wind, ice, or gravity. Chemical weathering is the alteration of rocks by chemical reactions, such as oxidation, hydrolysis, or acidification. Biological weathering is the decomposition of rocks by living organisms, such as plants, animals, fungi, or bacteria.
Also, particles from other places might be introduced through deposition, which is the process of adding material to the soil from wind, water, or ice. Once a small layer of soil has been formed, moss and other small vegetation begin to grow. These plants add organic matter to the soil through their roots and leaves, and also help retain moisture and nutrients. As the soil becomes more fertile, more plants and animals colonize the area, creating a complex ecosystem. The soil also develops different layers, or horizons, that have distinct physical and chemical properties. The main horizons are:
– O horizon: The top layer of organic matter, such as leaf litter, decomposing plants and animals, and humus (a dark, crumbly substance that is rich in nutrients).
– A horizon: The topsoil, which is a mixture of organic matter and mineral particles. This is the most fertile layer of soil and supports most plant growth.
– E horizon: The eluviation, or leaching, layer, which is a zone of loss of minerals and organic matter due to water percolating through the soil. This layer is often light in color and low in nutrients.
– B horizon: The subsoil, which is a zone of accumulation of minerals and organic matter from the upper layers. This layer