Lecture 1 Flashcards
Who defines soil as “the lose surface of the earth”
Foth (1978)
Soil is the uppermost layer of mineral and organic matter found on the earth’s surface. Whose words are these?
MacDonald(2003)
Soil is a dynamic natural body on the surface of the earth in which plants grow composed of mineral, organic material and living forms. Who gave this definition?
Buckman and Brady (1960)
Soil is found on the surface of the earth in which plants grow. Does that mean stagnant water bodies on which plants grow are also soil?
NO!
Soil according to Buckman and Brady’s definition must be…
organic, inorganic and living forms
Humus is an example of…
an organic material
Living forms that just be present in the soil are….
Fauna (insects, bacteria)
Soil is a weathered product of rocks and minerals weathering…which point of view is this?
Pedological point of view
Soil is the natural medium for plant growth. Which POV is this?
Agricultural POV
Soil is a foundation material for construction. Which POV is this?
Engineering POV
What percentages are the following soil composition.
1. Mineral component
2. Organic matter
3. Air
4. Water
- 45%
- 5%
- 25%
- 25%
Which soil composition provides mechanical supportand nutrients for the plant?
Mineral component
I am made up of plant and animal residues and living organisms, I affect physical, chemical and biological properties of the soil. Who am I?
Organic Matter
Which composition prevents CO2 toxicity?
Air
I act as a reservoir for supplying plants with water, what am I?
Soil water
Soil formation is also known as
Pedogenesis
Soil formation begins with
The weathering of rocks or parent material
The breakdown of rocks, soils and minerals through physical, chemical and biological processes is called?
Weathering
What are the three types of weathering?
Physical, chemical and biological
A layer in the soul which measures parallel to the soil surface and possesses properties which differ from layers beneath and above is…
Soil horizon
The vertical sequence of soil horizons found at a given location is collectively called
Soil profile
What are the processes involved in soil formation?
Transformations, translocations, additions and losses of materials
What happens during transformations?
weathering and organic matter breakdown
Moving of inorganic and organic materials from one horizon to another mostly by water and soil organisms is under what process in soil formation?
Translocations
In the addition process
materials are added to the soil profile from outside such as organic matter from leaves, and dust
How do losses of materials happen?
through erosion
what capital letters are used to denote the master or main horizons
O, A, B, C, E
Primarily dead organic litter. Most soils inhabit this layer
O layer
Later rich in humus consisting of partly decomposed organic material mixed with mineral soil.
A layer (top soil)
Region of leaching minerals from the soil
E layer
What is Eluviation ?
The downward movement of dissolved or suspended material within the soil by leaching.
which region or layer has little organic material?
B
Clay minerals and oxides of aluminum and iron leached out of the overlying E horizon are sometimes deposited in which horizon?
B horizon
Which major soil horizon has primarily weakly altered material similar to the parent material?
C horizon
I have calcium and magnesium carbonates accumulating in my layer, sometimes forming hard, impenetrable layers. What am I?
C horizon
Unaltered parent material such as rock can be found in horizon….
R
What are the four major soil orders representing ages and stages of soil development?
Entisol, Inceptisol, Alfisol and Ultisol
Entisol is a…
recently developed soil where weathering hasn’t exactly started.
What small layers are in the Entisol?
O, A, C, R
What dominant bottom layer is in the Entisol?
Layer R
Inceptisol marks the…
Inception of soil formation.
What happens to the layers in inceptisols?
Layer B appears, C grows larger and R becomes smaller
Alfisols are…
halfway weathered soils
what happens to the layers in the Alfisol
layers B and C continue to grow as layer R continues to shrink
Ultisol is the….
ultimate result of weathering
In the final stage of the major soil orders, what happens to the existing layers?
Layer R disappears completely, layer E has appeared and layers B and C have continued to grow.
All soils have horizons mentioned in this lecture, true or false?
False
Variations of soil profiles are due to…
differences in soil-forming factors
Variations of soil profiles are due to…
differences in soil-forming factors
not a question but shortcut to remember.
O, A, E, B, C, R
O- organic horizon
A- top soil
E- Eluviation horizon
B- subsoil
C- Parent material
R- bedrock
What is the sentence we made out of the characteristics of major soil horizons?
Oh Alpha Ends Beta Career Regardless
Biota is…
vegetation or humus and burrowing animals
