WELCOME TO
OUR
EARTH
SCIENCE CL ASS
SOIL
AND
SOIL
PROFILE
SOIL
forms the pedosphere
living skin of the earth which is a result of the interaction
among the atmosphere, biosphere, geosphere,
and hydrosphere
“pedon” – soil “sfaira” – sphere
the result of the process of the gradual breakdown of rock - the
solid geology that makes up the earth. As rock becomes broken
down through certain processes, such as weathering and
erosion, the particles become ground smaller and smaller.
SOIL PROFILE
an important tool in nutrient As the soil weathers and
management organic matter decomposes,
a vertical section of the soil the profile of the
from the ground surface
downwards to where the soil
meets the underlying rock
By examining a soil profile,
we can gain insight into soil
fertility.
soil changes.
FACTORS THAT AFFECT SOIL FORMATION
1. Climate – temperature, rainfall and moisture affects the pattern
of soil-forming processes
2. Biological factors
• animals - mix the soil through burrowing
• plant roots - aid in weathering processes
• microorganisms - affect nutrient and chemical exchanges
between roots and soil
• human activities like agriculture and urbanization
3. Relief/ Topography
– the gradient of the slope affects water flow and erosion
– where water and other materials accumulate on or leave the
landscape
COMPONENTS OF SOIL
45% mineral (gravel, sand, silt, and clay)
25% air
25% water
5% organic matter (humans, roots, dead and decaying
organisms)
COMPONENTS OF SOIL PROFILE
Soil horizon - makes up a distinct layer of soil
Regolith - includes all of the weathered material within
the profile
a. Solum - upper horizons with the most weathered
portion
SOIL TEXTURE
- relative proportion of the agricultural use
particle sizes in soil
clay (<0.002 mm)
silt (0.002-0.005 mm)
sand (0.005-2.00 mm)
gravel and rock (>75.00 SOIL TEXTURAL TRIANGLE
mm)
Loam – ideal soil for
MASTER HORIZONS
O horizon (organic horizon)
- a surface horizon that is comprised of organic material at
various stages of decomposition
- most prominent in forested areas where there is the
accumulation of debris fallen from trees
A horizon (surface horizon)
- consists of minerals (sand, silt, and clay) and with
amounts
of organic matter
- predominantly the surface layer of many soils in
E horizon
- characterized by a significant loss of minerals
(eluviation)
and leaching
Leaching - process in which soluble nutrients are lost
from the soil due to precipitation or irrigation
- typically light in color
B horizon (subsoil)
- accumulated clay and other nutrients from the layers
above it
C horizon (substratum)
- least weathered horizon
- composed of loose or partly decayed organic matter
- also known as saprolite; it is an unconsolidated,
loose
parent material
R horizon
- hard bedrock
SOIL ORDERS
1. Gelisols – frozen soils found
2. Histosols – high organic content and wet
3. Spondosols – sand and acidic soils found in moist climates
4. Andisols – composed of volcanic ash
5. Oxisols – very weathered and common in tropical climates
6. Vertisols – claylike soils that shrink and swell
7. Aridisols – very dry soils in arid regions
8. Ultisols – weathered soils
9. Mollisols – deep and fertile soils
10.Alfisols – moderately weathered soils
11.Imceptisols – slightly developed young soils
12.Entisols – newly formed soils
WHAT TO DO?
1.HOW DO FARMING AND URBANIZATION
IN THE PHILIPPINES AFFECT THE QUALITY
AND QUANTITY OF THE SOIL?
2. WHAT WOULD THE WORLD BE
WITHOUT SOIL?
3.WHAT ARE THE FACTORS THAT AFFECT
THE CHARACTERISTIC OF THE SOIL?
WHAT CAN I DO ABOUT IT?
WHAT HUMAN ACTIVITIES
ARE DEPENDENT ON THE
USE OF SOIL AS A RESOURCE
AND HOW DO THESE
ACTIVITIES AFFECT THE SOIL
QUALITY?
