Download Soil Formation and Classification: Pedons, Weathering, Rocks, and Soil Horizons and more Slides Botany and Agronomy in PDF only on Docsity! Soil Origin and Development Docsity.com Soil Body • Terms to know: – Pedon is a section of soil extending from the surface to the depth of the root penetration of the deepest rooted plants. – Polypedon a collection of pedons that are much the same. – Weathering it is where weather, plants are the major agents responsible for forming soil from rock. Docsity.com Rocks and Minerals • Metamorphic Rock: – This is where igneous and sedimentary rocks are subjected to great heat and pressure so they change to metamorphic rock. Docsity.com Rocks and Minerals • Sedimentary rock- • Is like limestone or sandstone,formed by deposition of materials in water or by wind. Note: fresh mud and sand that will someday be sedimentary rock. • Igneous rock- • like basalt,formed from molten rock as in volcano. Most of the earth’s crust is igneous rock overlain by sedimentary rock Docsity.com Rocks and Minerals • Metamorphic rock- has been altered by heat, pressure or chemical action. Examples are limestone becomes marble and sandstone becomes quartzite. Docsity.com Rocks and Minerals • What is Glacial Till- – It is the melting process where some debris simply dropped in place to form deposits. Eolian is where the wind will carry and leave soil somewhere else. Alluvial Soils- are soils whose parent materials were carried and deposited in moving fresh water to form sediments Docsity.com Rocks and Minerals • Colluvium- – this is where the soil will slide down or roll down a slope. This is scattered in hilly and mountainous areas – Some examples are: Avalanches, mudslides, and landslides. Docsity.com The Soil Profile • Soil does change over time today Scientist have classified them into four areas • They are: – Addition – Losses – Translocations – Transformations Docsity.com The Soil Profile • What is Translocation? – It is materials that may be moved within the soil as with leaching deeper into the soil or being carried upward with evaporating water. Docsity.com The Soil Profile • What is Transformation? – It is the materials that may be altered in the soil, for example organic matter decay weathering of the minerals to smaller particles or chemical reactions. Docsity.com The Soil Profile • Each of these processes will occur at different depths of the soil. • For example: – Organic Matter will be at the top or the near the surface of the soil. Docsity.com Master Horizons • What is the Master Horizons? – The are A, B and C horizons are known as the master horizons. They are a part of a system for naming soil horizons in which each layer is identified by a code O, A, E, B, C and R Docsity.com Horizons • The O Horizon- – Is the organic layer made of wholly or partially decayed plant material and animal debris . You can normally find this layer in a forest with fallen leaves, branches and other debris. Docsity.com Horizons • The A Horizon- – It is usually called the topsoil by most farmers. This is where the organic matter accumulates over time. This layer is very prone to leaching and losing iron and other minerals. The A horizon provides the best environment for the growth of plant roots, microorganisms and other life. Docsity.com Horizons • The C Horizon- – lacks the properties of the A and B horizon. It is the soil layer that is less touched by soil forming processes and is usually the parent material soil Docsity.com Horizons • The R Horizon- – Is the underlying bedrock such as the limestone, sandstone, and or granite. Docsity.com
