Pedosphere PDF

At the end of the lesson, I will be able to: Define soil and the pedosphere. Describe the components and layers of the soil profile. Explain the importance of soil as a natural resource and its role in supporting life on Earth. Understand the processes of soil formation and factors inf...

At the end of the lesson, I will be able to: Define soil and the pedosphere. Describe the components and layers of the soil profile. Explain the importance of soil as a natural resource and its role in supporting life on Earth. Understand the processes of soil formation and factors influencing soil properties.  Soil is an essential component of Earth that has enabled life to exist on the planet and continues to support it. the soil forms the PEDOSPHERE  The foundation of terrestrial life on this planet. The term is derived from the greek words pedon which means “soil” and sfaira which means “sphere” The pedosphere is the living skin of Earth which is a result of the dynamic interaction between the atmosphere, biosphere, geosphere, and hydrosphere. The soil is made from a portion of the geosphere, atmosphere, hydrosphere, and biosphere.  Soil forms when rocks weather. Weathering breakdown rocks, as a result of physical or chemical changes. soil formation may be a slow or rapid process, depending on the factors at play.  SOIL TEXTURE- is defined as the relative proportion of the particle size in the soil. The particles that make up soil are categorized into three groups by size (sand, silt, and clay)  SAND particles ranges between 2.0 and 0.05 mm; SILT, 0.05 mm, and 0.002 mm; and CLAY, less than 0.002 mm.  particles larger than coarse grained sande are gravel and rock if they are larger than 75.00mm The texture of soil depends on the percentage of clay, silt and sand it has LOAM is the ideal soil for agriculture LOAM provide good aeration and drainage properties of large particles with nutrients retention and water holding abilities of clay particles 12 Types of Soil Texture Sand Sandy Clay Loam Loamy Sand Clay Loam Sandy Loam Silty Clay Loam Silty Clay Loam Silt Sandy Clay Silt Loam Clay ACTIVITY 1 Use the following numbers to determine the soil texture name using the textural triangle. When a number is missing, fill in the blanks. Note: the sum of percent of sand, silt, and clay should add up to 100 percent. % SAND % SILT % CLAY TEXTURE a. 75 10 15 Sandy loam b. 10 83 7 c. 42 37 d. 52 27 e. 35 50 f. 30 21 g. 5 70 h. 55 40 i. 45 10  A soil profile shows the sequence of the soil horizon Soil scientists use capital letters O, A, B, C, and E to identify soil horizons. Most soil has 3 major horizons A, B, and C. Surface horizon (A) Also called “Topsoil”, is composed of mineral matter mixed with some dark organic humus. Subsoil horizon (B) is the accumulated clay and other nutrients from the laters above it Substratum horizon (C) is composed of partially altered parent material Some soil have: Organic horizon (O) on the surface composed of loose or partly decayed organic matter Horizon (E) that is characterized by a significant loss of mineral eluviation and leaching Horizon (R) is the hard bed rock is not soil Soil scientists also developed a soil classification system to identify, understand, and manage soils. The most general level of classification is the soil order consisting of 12 types  lEntisols Ultisols Inceptisols Oxisols Andisols Gelisols Mollisols Histosols Alfisols Aridisols Spodosos Vertisols  Soil Order Description 1. Entisols A. Soils that are very young and have little to no horizon development. 2. Inceptisols B. Soils that are moderately developed, typically found in humid areas with some horizon formation. 3. Andisols C. Volcanic soils that are rich in organic matter and have high nutrient retention capabilities. 4. Mollisols D. Fertile soils found in grasslands, characterized by a thick, dark surface horizon rich in organic matter. 5. Alfisols E. Soils that are fertile and typically found in temperate forests, with a clay-rich subsoil. F. Acidic soils found in cool, humid climates, characterized by a leached horizon and accumulation of iron and aluminum 6. Spodosols oxides. 7. Ultisols G. Highly weathered soils found in humid temperate and tropical regions, often low in nutrients. 8. Oxisols H. Very old, highly weathered tropical soils that are low in fertility and rich in iron and aluminum oxides. 9. Gelisols I. Soils of cold regions, often containing permafrost and characterized by cryoturbation effects. 10. Histosols G. Organic-rich soils typically found in wetlands or peatlands, with a high percentage of decomposed plant material. 11. Aridisols K. Soils of arid regions, characterized by low organic matter and high salinity levels due to evaporation. 12. Vertisols L. Clay-rich soils that swell when wet and shrink when dry, often cracking significantly during dry periods. 1. Gelisols - Frozen soils found in the coldest regions on Earth 2. Histosols - High organic content and wet 3. Spodosols - Sandy and acidic soils found in moist climates that often support dense forests 4. Andisols - Composed of volcanic ash 5. Oxisols - Very weathered and common in tropical climates 6. Vertisols - Claylike soils that shrink and swell 7. Aridisols - Very dry soils in arid regions 8. Ultisols - Weathered soils 9. Mollisols - Deep and fertile soils 10. Alfisols - Moderately weathered productive soils found in temperate and humid regions 11. Inceptisols - Slightly developed, young soils found on steep slopes and mountain ranges 12. Entisols - Newly-formed soils found in steep rocky lands  Soil is important because? 1. Arable for Agriculture 2. Regulating water and other pollutants 3. Nutrients Cycling 4. Foundation and support 5. Mineral Deposit 1. Soil Erosion 2. Soil Compaction 3. Desertification 4. Intensive Agriculture 5. Urbanization 1. Increase Soil Organic matter 2. Keep soil Covered and vegetated 3. Avoiding excessive tillage 4. Managing pest nutrient efficiently 5. Promoting crop rotation 6. Reducing erosion and preventing soil compaction