Soils

Soils

1. How is soil formed?

   • Rocks that are slowly decomposed by:
     • Sun.
     • Wind.
     • Water/Rain.
     • Animals and plants.

2. Main types of soils:

   • Clay.
     • Smallest particles.
     • Least permeable type.
   • Sand.
     • Biggest particles.
     • Most permeable type.
   • Silt.
     • Size of particles: smaller than sand's particles but bigger than clay's particles.
     • Permeabilty: in between sand and clay.
   • Loam.
     • Best type because it is a mixture of the other three.

3. Soil erosion:

   • Action of surface processes that removes soil from one location and transport it to another one.
     • Forests and plants protect the soil so, when they are removed, they accelerate soil erosion.

4. Factors that influence soil formation: CLORPT.

   • CL: Climate.
     • Rainfall.
     • Temperature.
     • Humidity.
   • O: Organisms.
     • Animals.
     • Plants and trees.
     • Bacteria and fungi.
   • P: Parent material.
   • T: Time.
   • R: Relief.

5. Soil horizons:

   • O (organic) horizon:
     • Where dead plants and animals are.
   • A horizon:
     • Where most soil organisms are.
     • "Biomantle".
   • B horizon:
     • Where roots are.
   • C horizon:
     • Rocks with some soil.
   • R (rock) horizon:
     • Just rock.

6. Soil orders:

   • Entisol:
     • No development of the soil horizons.
     • Very young.
     • Most common of the world.
   • Inceptisol:
     • More horizon development that the Entisoil.
   • Gelisol:
     • Permafrost.
     • Little horizon development.
   • Spodosol:
     • In coniferous and boreal forests.
     • Acidic.
     • Low fertility.
   • Alfisol:
     • Rich in Iron and Aluminium.
     • Deciduous forests and Mediterranean climates.
   • Andisol:
     • Volcanic soils.
     • Rich in nutrients.
   • Ultisol:
     • Red because of the iron.
     • Subtropical and humid locations.
   • Aridisol:
     • Desert soils.
     • NOT SAND DESERTS!
   • Mollisol:
     • Dark soil.
     • The best for agriculture.
     • Grassland.
   • Oxisol:
     • Low soil fertility.
     • Very developed horizons, but hard to see because of the iron.
     • Rainforest soils.
   • Histosol:
     • Wetland soils.
     • Contain peat and organic matter.
     • Acidic and unstable.
   • Vertisol:
     • High clay content.
     • Dry out regularly.

7. Preservation:

   • Soil is a sensitive living being, not a factory.
   • Everyone has a right to soil.
   • We can't bury soil under asphalt.

8. Economic exploitation:

   • Rich people misuse soil for economic pursposes.