Transcript Soil System
Soil System Soil Importance • Essential to how ecosystems work – Source of nutrients – Basis for root systems – Habitat for millions of plant and micro- and macro-organisms – Acts as filter, recycling system, and pollution control mechanism Soil Components • Broken down rock – Sand, silt, clay, pebbles, or other rock • Organic matter – Old leaves, dead animals or plants • Water • Air Soil Formation 1. Breakdown or weathering of rocks – Caused by the actions of water, wind, or ice 2. Presence of living organisms 3. Decomposition of dead organisms Soil Profile O horizon A horizon B horizon C horizon The O layer – high quality organic matter, with living and dead organisms in different stages of life and decomposition. Usually dark in color due to rich humus layer form the decomposition The A level – also called the upper soil layer and contains plant roots, bacteria, fungi, and other decomposers The B layer – contains less oxygen due to depth below the surface so has fewer roots and living organisms The C level – consist of sand, clay or pebbles and rock. Very little living or dead organic matter. Often Yellow or orange Soil Composition Name Very coarse sand Coarse sand Medium sand Fine sand Very fine sand Silt Clay Particle Diameter 2.0 to 1.0 millimeters 1.0 to 0.5 millimeters 0.5 to .25 millimeters .25 to .10 millimeters .10 to 0.05 millimeters 0.05 to 0.002 millimeters Below 0.002 millimeters Soil Texture Triangle