Read the summary and the most important questions on Principles of Soil Processes

• 1 Lecture 1

• How does a soil become into existence?

  1. Parent material
     
  2. Organisms invade this new space and create a new habitat. These organisms are very small and can survive extreme conditions.
  3. Groups of organisms are able to live at the surface and in the top of the new sediment.
  4. Organic matter and nutrients start to accumulate.
  5. A newly formed A horizon is formed.

• Why do primary minerals (formed in the interior of the Earth) weather into secondary minerals near the Earth surface?

  Because primary minerals are formed under very different conditions than the the conditions present at the Earth surface. The mineral is physically and chemically adjusted to new equilibria.

• What is physical weathering?

  An increase of surface area per volume or weight of rock

• Of what does a soil consist?

  Solid mineral particles (40-60%), organic matter (2-10%), water and air (pore space, 30-45%).

• 2 Lecture 2

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• What is soil particle density?

  The mass per volume of individual soil particles

• What is the dry bulk density?

  The weight of a soil (without water) per volume of the total soil

• The equivalent depth of soil water is defined as:

  The volumetric water content multiplied with the total soil depth

• 5 Lecture 5

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• The energy state of water in the ground is determined by:

  Gravity and the matrix forces (adhesion (clinging together of dissimilar particles), cohesion (clinging together of similar particles), and osmotic forces)

• How does capillary force work?

  Adhesion forces are present between the solid phase and water, and cohesion forces are present between the water molecules. So, the water that sticks to the soil moves along a capillary in the soil, and pulls along the other water particles

• What is the gravitational/elevation head z?

  The potential energy per unit weight of water at a height z above the chosen reference level