The document discusses the physical properties of soil, including its formation from weathering rocks, composition of solid, liquid, and gas phases, texture determined by sand, silt and clay content, structure defined by arrangement of particles, density, porosity, temperature, and classification of soil water. Key topics covered are the three phases of soil, factors influencing soil color, common soil structures like platy and granular, and definition of terms like bulk density, field capacity, and permanent wilting point.

2.  The ground(soil),Physical behavior of soil, Water
system, soil mechanics.
The ground(soil),Physical behavior
of soil, Water system, soil mechanics.

3.  PRESENTED BY
 UM E HABIBA

4. Physical Behavior
of Soil:

5.  The word soil derived from Latin word “Solium” Which
means upper layer of earth surface.
 Having different meanings for different professions
 For agriculture:
 It is loose surface material of earth in which plants grow.
 For geologist:
 It is the material which is produced as a result of disintegration
of rocks. Which has been transported from its original
positions.
 For engineers:
 Soil is uncemented accumulation of minerals or organic
particles occurring in zone overlying the rock crust.

6.  “The upper layer in which plants grow , a black or dark
brown material typically consisting of mixture of
organic remains , clay and rock particles.”
 What formed soil?
 Soil is thin layer of material covering the earth’s
surface.
 It is formed from weathering of rocks.
 It contain minerals , water and living organisms.

7.  It causes the disintegration of rock near the earth
surface.
 Its major causes are plants , animal life , atmosphere
and water.
 There are two types of it.
 Mechanical weathering
 Chemical weathering

8.  It transform original material into substances with
different composition and different physical
characteristics.
 Newly formed material is more softer and susceptible
to the agent of erosion than original material.
 3 phases of soil:
 The three phases of soil are as follow:
 SOLID
LIQUID
GAS

9.  Sandy soil
 Silt soil
 Clay soil
 Loamy soil
 Chalky soil
 Peaty soil

10.  Contain mineral particles.
 Having water ,air, and organic matter.
 The combination of these determined the
properties of soil.

11.  The arrangement and organization of primary
and secondary particles in a soil known as
soil structure.
 Structure is described under three categories:
 Type – shape or form and arrangement
pattern of peds.
 Class- size of peds.
 Grade – degree of distinctness of peds.

13.  Plate like
 Prism like
 Block like

14.  Climate.
 Organic matter.
 Plant roots and residues.
 Exchangable cations.

15.  Soil color is due to the reflection of EMR by different
soil constituents like minerals organic matter, water,
salts etc.
 The occurrence of two or more patches of color is
called mottling (due to the presence of iron, manganese
and copper in soil in patches).
 Soil colour is inherited from the parent material and
that is referred to as lithocromic . Eg: red soils
developed from red sand stone.

16.  Soil colour is measured using Munsell colour chart and
expressed in terms of Hue, value and chroma.
 Hue denotes the dominant spectral color.
 Value denotes the intensity of color.
 Chroma indicates the purity of color.
 10YR 5/4 means , the Hue value is 10YR, 5 is the value
and 4 is the chroma.

18.  Parent material.
 Soil moisture.
 Organic matter.
 Mixture of organic matter and iron oxides.
 Alternate wetting and drying condition

19.  Relative portion of sand silt and clay .
 Mechanical analysis hydrometric method.
 Textural Classes:
 The proportions of predominant size of fractions of
sand silt and clay is the
basis for classification of soil texture.

21.  Arrangement of soil particles.
 Individual aggregates are known as peds or
secondary units.
 Two forms of structure less conditions are
recognized ;
 Single grain
 Massive

22.  Platy: -In recently deposited clay soil.
 This structure is commonly found in soil layers that
have been compacted.
 Prism: Vertically oriented
 When the tops are flat, these vertical aggregates are
called prismatic.
 These elongated columns vary in length with
different soil.

23.  These structures is commonly seen in soils with high
clay content and
 in horizons dominated by high shrink-swell clays.
 When rounded they are known as columnar .
 Most commonly seen in soils that have sodium
content in a dry climate.

24.  The original aggregates have been reduced to blocks
and basically equal in height, width and depth.
 Blocky structure is the most common type of
structure seen in the subsoil (B horizon) in North
Carolina.
Rounded aggregates usually less than 1/4 inch in
diameter .
 These complexes lie loosely on the surface and are
readily shaken apart.
 These are called granules and the pattern is called
granular .

25.  Each individual soil particle is separate and there is
no structure.
 This is only found in very sandy soils and is the type
of structure commonly seen in sand dunes at the
beach.
 Wedge:- The aggregates resemble wedges thinner at
one end and thicker on the
 other end.

26.  The weight of an individual soil particle per unit
volume is called particle density.
Typical particle densities for soils range from 2.60
to 2.75 g/cm3.
 However they can be as high as 3.0 g/cm3 for very
dense particles and as low as 0.9 g/cm3 for organic
particles

27.  Bulk density is the mass of dry soil per unit volume
including the airspace.
 It has major effect on the movement of air and water
in soils.
 Solis with high bulk densities are often compacted.
 Soil compaction restricts rooting depth which
reduces the uptake of water and nutrients by plants.

28.  The pore space of soil contains the liquid and gas phases
of soil ,everything but the solid phase that contains
mainly minerals of varying sizes as well as organic
compounds.
 Soil porosity is important for many reasons.
 A primary reason is that soil pores contain the
groundwater that many of us drink.
 Another important aspect of soil porosity concerns the
oxygen found within these pore spaces. All plants need
oxygen for respiration so a well-aerated soil is important
for growing crops.
 Clay soil have the highest porosity and sand the lowest

29.  Resistance of soil material to deformation or rupture.
 Rupture resistance is a measure of the soil’s ability to
withstand applied stress. For this test moist soil is
normally used.
 Plasticity is the degree to which a reworked soil can
be permanently deformed without rupturing.

30.  Soil air is a continuation of the atmospheric air .
 Unlike the other components it is constant state of
motion from the soil
 pores into the atmosphere and from the atmosphere
into the pore space.
 Composition of air in soil and atmosphere:-Nitrogen:
Soil Air: 79.2% and Atmosphere: 79.0%
 Oxygen: Soil Air: 20.6% and Atmosphere: 20.9%
 Carbon Dioxide: Soil Air: 0.25% and Atmosphere:
0.04%

31.  Soil temperature is simply the measurement of the
warmth in the soil.
 Ideal soil temperature for planting most plants are 65
to 75 F ( 18 to 24C)
 Night time and day time soil temperatures are both
important.
 Soil functions as a major storage mechanism of heat,
collection energy throughout the day and releasing heat
to the surface during the night

32.  Physical classification of soil water:-
 1. Hygroscopic
 2. Capillary
 3. Gravitational
 Field capacity
 Permanent wilting point
 Hygroscopic Coefficient