1. | Jul 2012| © 2012 UPES

2. Jul 2012
Jul 2012 © 2012 UPES

3.  The lithosphere is the solid, rocky crust covering entire planet.
 Also known as crust. This crust is inorganic and is composed
of minerals. It covers the entire surface of the earth from the
top of Mount Everest to the bottom of the Mariana Trench.
 Silica and Aluminium dominate in this layer and hence it is
sometimes called „Sial‟.
 Its average thickness is about 20 kms ( 8-40 kms)
 It is thin below ocean beds and thick in continents.
 Crust comprises 0.4 % of the total mass of earth.
Jul 2012
Jul 2012 © 2012 UPES

4. Soil is the topmost layer of earth‟s surface which is composed of
mineral and organic matter and is capable of sustaining plant life.
Word soil has been derived from latin word „solum‟ which means
topmost layer of crust.
It is a dynamic layer of crust which goes on changing and
developing constantly.
Soil is formed by wear and tear of the crust, a process which has
been going on through the ages. This process is called
weathering ( discussed in previous unit)
Jul 2012
Jul 2012 © 2012 UPES

5. The main components of soil are:
 Inorganic material
It is parent material of soil. It is in the form of sand, silt, clay etc. which is
formed by wear and tear of rocks and minerals. The chemical
constituents of soil are nitrogen ( helps in growth of plants), phosphorus
(helps in the riping of grain and increases the yield), potassium
(determines the quality of grain), calcium ( helps in growth of leaves
which in turn provide food to plants) etc.
 Organic Material
Organic matter is added to soil by dead animals and vegetation matter.
This matter is decomposed by microorganisms to form humus. Humus
helps in cementing the lose particles of sand, silt and clay; provides
food to plants; improves water retention power of soil.
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6.  Water
 Air
 Microorganisms
These decomposers decompose dead animals and plants. They
utilize the organic matter, derive energy and release inorganic
substances. They fix atmospheric nitrogen. Animals like
earthworms keep the soil porous.
Jul 2012
Jul 2012 © 2012 UPES

7. Depending on their origin
Residual soils ( Diluvial).
This type of soil is found at its place of formation. Such soils are
common on hill slopes, foot hills or in the course of river
 Transported Soil (Alluvial)
This type of soil is formed by deposition of material transported by
river, wind etc. Alluvial soil in gangetic planes is a good example.
Jul 2012
Jul 2012 © 2012 UPES

8.  For determining the quality of soil,
the surface features and
characteristics as well as the
characteristics in depth need to be
studied.
 The depth of the soil can be studied
with the help of a soil profile.
 A soil profile is a vertical section
through the soil downwards from
surface to the parent rock bed.
 In a profile several characteristic
layers can be seen. These layers are
called horizons
 The individual horizons are given
names, generally they are known as
O, A,B,C and R horizon
Jul 2012
Jul 2012 © 2012 UPES

9. The 6 Soil Roles
A Soil’s role includes:
• Serving as a foundation
• Emitting and absorbing gases
• Providing habitat
• Interacting with water
• Recycling nutrients
• Supporting human settlements
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Jul 2012 © 2012 UPES

10. The 5 Factors of Formation
Soil is formed by…
• Parent Material: the original “Mom & Pop” soil transported from
elsewhere, usually by wind or water, at different speeds
• Climate: the amount, intensity, timing, and kind of precipitation that
breaks down parts of ecosystem (i.e. rocks, trees) into soil
• Topography: Slope and Aspect affect the angle of the land and
position toward/away from the sun that soil will be exposed to
• Biological: Plants, animals, microscopic organisms, and humans
interact with soil in different ways
• Time: the amount of time it takes for the four factors (above) to
interact with each other
Jul 2012
Jul 2012 © 2012 UPES

11. The “Organic Matter” Horizon
•Surface-layer, at depths of 0-2 feet
•Dark in color, soft in texture
•Humus - rich organic material of plant and
animal origin in a stage of decomposition
•Leaf litter – leaves, needles, twigs, moss,
lichens that are not decomposing
•Several O-layers can occur in some soils,
consisting only of O-horizons
-O1 : When the organic matter is in its
original vegetative form i.e. undecomposed
loose leaves and other organic matter
-O2: When organic matter is completely
decomposed
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Jul 2012 © 2012 UPES

12. • Topmost layer of mineral soil, at depths
of 2-10 feet
• Some humus present, darker in color
than layers below
• Biomantle - most biological productive
layer; earthworms, fungi, and bacteria live
this layer
• Smallest and finest soil particles
• A1- It is dark colored layer composed of
organic matter and particles of minerals
and rocks. It has high content of organic
matter
• A2- It is light coloured layer composed of
mainly particles of rock and minerals
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Jul 2012 © 2012 UPES

13. The “Subsoil” Horizon
• At depths of 10-30 feet
• Rich in sand, silt and clay and minerals
like Fe & Al
• Some organic material may reach here
through leaching
• Plant roots can extend into this layer
• Red/brown in color due to oxides of Fe &
clay
• Its sub divisions are B1, B2, B3 etc.
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Jul 2012 © 2012 UPES

14. The “Regolith” Horizon
• At depths of 30-48 feet
• Made up of large rocks or lumps of
partially broken bedrock
• Least affected by weathering and
have changed the least since their
origin
• Devoid of organic matter due to it
being so far down in the soil profile.
• The material may be cemented by
calcium carbonate, alkali, silica etc.
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Jul 2012 © 2012 UPES

15. The “Bedrock” Horizon
• At depths of 48+ feet
• Deepest soil horizon in the soil
profile
• No rocks or boulders, only a
continuous mass of bedrock
• It is underlying consolidated and
unweathered parent bed rock
such as granite limestone etc.
• Colors are those of the original
rock of the area
Jul 2012
Jul 2012 © 2012 UPES

16. INGREDIENTS DIRECTIONS
• 3-4 copies of Master Soil Horizons Worksheet 1. In large glass bowl, whisk 3.5 cups milk with 2
• 30 sticky notes per group (7 per person) pkgs. vanilla Instant Jell-o pudding mix until
smooth. Let stand 5 minutes.
• 3-4 pairs of gloves
• 1 large glass bowl 2. While waiting, refer to your version of “The Soil
Profile” powerpoint to review order that horizons
• 1 one-cup measuring cup should be. You have A, E, B, R, O, C, and
• 1 whisk vegetation as horizons. It‟s up to you to order it!
• 1 spatula 3. After 5 minutes, use spatula to scoop pudding in
• 3.5 cups skim milk middle of bowl, allowing for the “dry ingredients”
(the bags of various crushed up cookies) to
• 2 packages vanilla Instant Jell-o pudding mix
encircle the pudding along the sides of the glass
• 1 tiny Ziploc bag Coconut w/green food bowl. This creates a vertical cross-section of soil
coloring + raisins layers visible to you.
• 1 small Ziploc bag crushed chocolate graham
4. Use sticky notes to label each horizon on outside
crackers & frosting
of bowl.
• 1 medium Ziploc bag Chocolate chip & Vanilla
wafers & gummy worms 5. Fill out Master Soil Horizons Worksheet using
observations of Soil Profile Dessert.
• 1 small Ziploc bag crushed Vanilla wafers only
• 1 medium Ziploc bag crushed graham crackers 6. Turn in worksheet to teacher. Only until you and
your team members turn in their worksheet can
• 1 large Ziploc bag crushed Oreo cookies you enjoy the delicious snack. You‟re finished!
• 1 large Ziploc bag crushed chocolate chips
Jul 2012
Jul 2012 © 2012 UPES