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Soil systems 5.1 - Coggle Diagram
Soil systems 5.1
Structure
Forms the outermost layer of the Earth’s surface, and comprise weathered bedrock (regolith), organic matter (both dead and alive), air and water. It interacts with the lithosphere (rocks), biosphere (living matter) and hydrosphere (water).
Soil profile
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A Horizon = top soil, mix of partially decomposed organic and inorganic matter
B Horizon = subsoil, where soluble minerals and organic matter are deposited from layer above
C Horizon = parent material, weather rock from which the soil forms
O and A are most fertile, have highest concentration of organic matter and contain many living organisms
It is the complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air and living organisms.
The quality influences the primary productivity hence why deserts/tundra have low NPP
Transfers
Biological mixing = earthworms help mix the soil + create passages where air and water can travel promoting soil development.
Leaching = occurs when water flowing vertically transports nutrients. Can be carried into groundwater and then transported into rivers, lakes, oceans.
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Translocation = movement of soil-forming materials through the developing soil profile. Occurs by water running through the soil and transferring materials from upper to lower parts of the profile.
Inputs
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Precipitation = deposits sulfur, chloride, calcium, and sodium
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Transformations
Decomposition: Bacteria help break down leaf litter to form humus
- Particle size determines pore size which determines percolation rate and air content. Rate of decomposition depends on amount of air, water. and temp.
Good aeration = a lot + high decomposition rate = little humus
High water = poor aeration = low decomposition rate = dead plant material accumulates
Weathering : Adds nutrients to ecosystems in small quantities over long periods of time. E.g. calcium, magnesium, potassium, sodium.
Soil texture triangle
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Soil texture = size of soil particles. Affects moisture content, aeration, retention of nutrients, ease of cultivation and root penetration
Outputs
Soil erosion - most important way of nutrient loss. Erosion is active where cultivation and grazing leaves the soil unprotected. When unprotected, the surface of the soil is easily transported by wind and moving water (= full of nutrients)
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Soil has four functions:
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Habitat for organisms, such as bacteria, insects and mammals. These organisms modify the soil.
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