The uppermost layer of soil consists of humus, sand, mud and rock particles. Humus consists of decayed plants and animal remains. Weathering is the breaking down of rocks into smaller pieces through physical or chemical processes. Factors like climate, parent rock type and land slope determine the type of soil formed. The major soil layers are topsoil, subsoil and bedrock.

2.  The uppermost layer of the earth is known as
soil.
 This layer consists of sand, mud, and rock
particles.
 What is humus??
 Consists of dead and decayed plants and
animal remains called humus.

3. What Is weathering??
• The breaking down of rocks is known as
Weathering
• Wind , water , frost helps in transporting of
soil to places.
• There are two types of weathering :
– Physical weathering
– Chemical weathering

4.  Physical weathering is the process of breaking
of rocks into smaller pieces.
 These change do not involve any characteristic
change in the original rock .
 These are caused by the
-Temperature change,
-frost

5.  Chemical weathering is the process which
exists of mineral are broken down into mineral
components.
 Water is the main agents used in this
Process.

6.  What is weather??
The weather conditions prevailing in an area in
general or over a long period.
 Climate effects by the rain , wind , temperature
of an place

7. • Characteristic of the parent rock also determines the kind of
soil formed.
• Parent rock refers to the original rock from which
something else was formed.
• It is mainly used in the context of soil formation where
the parent rock normally has a large influence on the
nature of the resulting soil.

8.  Climate
 Characteristic of the parent rock
 Slope of land
 Climate : The weather conditions like the rain , wind
,etc plays an important role in loosing the soil.
Increasing of pressure can also cause make the rocks to
crack .Rocks are also worn down by wind.
 Soil formation is faster in hot and slow in
winter season.

9. step 1: Weathering is the physical or chemical
process.
Step 2: small rocks continue to undergo
weathering, causing large pieces of
parential rocks.
Step 3: minerals and salts seep deeper into
the ground along with water.

10. Humus and topsoil
 Humus is the organic component of
soil, formed by the decomposition of
leaves and other plant material by
soil microorganisms.
 is the uppermost layer of soil.
 this layer consists of humus and fine
particles of dust and sand.

11.  Contains weathered rocks.
 It is very difficult to dig more than this layer.
 the line at which the earth's surface and the
sky appear to meet.
___________________________________
Bedrock
 The lower most layer and consists of parent
rock.
 This layer is mainly consists of soil.
 _____________________________________

12.  this layer is also soft and can hold water
 O horizon lies just above this top soil
which is rich in organic matter.
 ________________________________
Sub soil
 Subsoil is rich in minerals that sweep
down along with the water .
 It also consists of fine particles of soil.
 ________________________________

13. what is regolith : the layer of solid material covering the bedrock of a
planet.

15. Humus
Top soil
Sub soil
Bedrock

17. Particles Diameter
Clay Less than 0.002
Slit 0.002 – 0.05
Sand 0.05 – 2.00
Fine bebbles 2.00 – 5.00
Medium pebbles 5.00 – 20.00
Coarse pebbles 20.00 - 75.00

18.  The 3 properties of soil are :
 Absorption of soil.
 Moister of soil.
 Percolation of water.
Percolation is the process of a liquid slowly passing through a
filter.

19.  Soil compaction, low organic matter,
loss of soil structure, poor internal
drainage, salinisation and soil acidity
problems are other serious issues.
 Surface water runoff occurs whenever
there is excess water on a slope that
cannot be absorbed into the soil or is
trapped on the surface.

20.  Sand soils are often dry, nutrient
deficient and fast-draining. They have
little ability to transport water from
deeper layers through capillary transport.
 tillage of sandy soils in the spring should
be kept to a minimum in order to retain
moisture in the seedbed.
 meaning of tillage :the preparation of
land for growing crops. the preparation
of land for growing crops.

21.  Clay is a fine-grained natural rock or soil
material that combines one or more clay
minerals with traces of metal
 variable amounts of water trapped in the
mineral structure. Depending on the
content of the soil, clay can appear in
various colours, from white to dull gray
or brown to a deep orange-red.

22.  Loam is soil composed mostly of sand
and a smaller amount of clay.
 Use in farming !!
 Loam is considered ideal for gardening
and agricultural uses because it retains
nutrients well and retains water while
still allowing excess water to drain away

23. 1
2 3

24.  Deforestation
 Overgrazing
 Flood and heavy rainfall
 Improper farming
 Plant more trees and cut less trees.
 Overgrazing in a same patch of land should be
avoided.
 Terrace farming should be adopted in hilly
areas.