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Soil and Productivity. Importance of Soil. Soil: the layer of material that covers the land Where plants anchor and grow Made of weathered rock, decomposing plant and animal matter Has spaces for air and water movement
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Importance of Soil • Soil: the layer of material that covers the land • Where plants anchor and grow • Made of weathered rock, decomposing plant and animal matter • Has spaces for air and water movement • Soils differ in organic content which effects the ability to support plant life.
Layers of composition • 3 major types of soil • Horizon A: Topsoil • Horizon B: Subsoil • Horizon C: Parent Rock • Horizon D: Bedrock • Each layer has different characteristics depending on where it is found.
Grasslands • Horizon A is deep and supports root growth; small particles of rock mixed with decaying plant and animals (Humas). • Horizon B is the subsoil (mix of dirt and rock). • Horizon C is mostly large pieces of rock. • Horizon D is bedrock solid rock.
Deserts • Horizon A: limited plant growth so little decomposition, so thin top soil or none at all.
Disturbing soils • Soils change over time naturally • Human impact: deforestation leads to increased erosion of topsoil (no roots to hold soil in place)
Productivity of Ecosystems • Ecosystems have different productivities, based on light availability, soil types, precipitation, temperature, nutrients. • Productivity: the quantity of biomass of plants produced each year on a given area (g/m2)
Sustaining life • Biotic: living part of the environment. Ex: plants and animals • Abiotic: non-living part of the environment. Ex: elements, air, and water.
The key events - respiration and photosynthesis • Photosynthesis takes carbon dioxide, water and energy to produce carbohydrates and oxygen. • Respiration takes carbohydrates and oxygen, combines them to produce carbon dioxide, water, and energy.