Post on 26-Dec-2015
SOIL DEGRADATION
Impacting The Environment
Mr. Stewart
WHAT IS SOIL?
SOIL
S
oil is the earth’s fragile skin that anchors all life on Earth. It is
comprised of countless species that create a dynamic and complex
ecosystem and is among the most precious resources to humans.
S
oil is the end product of the influence of the climate, relief
(elevation, orientation, and slope of terrain) , biotic activities
(organisms), and parent materials (original minerals) acting over
periods of time.
SOIL PROFILE
IDENTIFY
WHAT IS SOIL DEGRADATION?
SOIL DEGRADATION
S
oil degradation may be viewed as any change or disturbance to the soil perceived
to be deleterious or undesirable.
S
oil Degradation are broken down to
O
ne (Physical)
T
wo (Chemical)
T
hree (Biological) subgroups
SOIL DEGRADATION
WHAT IS SOIL COMPACTION?
SOIL COMPACTION
Soil compaction is the process in which a stress
applied to a soil causes densification as air is
displaced from the pores between the soil grains.
When stress is applied that causes densification due
to water (or other liquid) being displaced from
between the soil grains then consolidation.
DENSIFICATION
SOIL COMPACTION
Soil compaction is usually a combination of both
engineering compaction and consolidation, so may
occur due to a lack of water in the soil, the applied
stress being internal suction due to water
evaporation as well as due to passage of animal feet
and other factors such as heavy machinery.
COMPACTING METHODSS
tatic - a large stress is slowly applied to the soil and then released.
I
mpact - the stress is applied by dropping a large mass onto the surface of the soil.
V
ibrating - a stress is applied repeatedly and rapidly via a mechanically driven plate or hammer. Often combined
with rolling compaction (see below).
G
yrating - a static stress is applied and maintained in one direction while the soil is a subjected to a gyratory motion
about the axis of static loading. Limited to laboratory applications.
R
olling - a heavy cylinder is rolled over the surface of the soil. Commonly used on sports pitches. Roller-compactors
are often fitted with vibratory devices to enhance their ability.
K
neading - shear is applied by alternating movement in adjacent positions. An example, combined with rolling
compaction, is the 'sheepsfoot' roller used in waste compaction at landfills.
MEASURED
A
soil penetrometer can be used as a diagnostic tool to
measure the extent and depth of subsurface soil
compaction.
PENETROMETER
TIRE COMPACTION
COMPACTION
COMPACTION
ADVANTAGE
Roads
Housing
Lawns
DISADVANTAGES Causes soil pore spaces to become smaller
reduces water infiltration rate into soil
Decreases the rate that water will penetrate into the soil root zone and
subsoil
Increases the potential for surface water ponding, water runoff, surface
soil waterlogging and soil erosion
Reduces the ability of a soil to hold water and air, which are necessary for
plant root growth and function
Reduces crop emergence as a result of soil crusting
Impedes root growth and limits the volume of soil explored by roots
limits soil exploration by roots and decreases the ability of crops to take
up nutrients and water efficiently from soil
Reduces crop yield potential
MANAGEMENT
T
raffic control
-Reduce
overall soil compaction in a field
-Improve soil
structure
-Increase
water infiltration
-Increase soil
water storage
-Increase
moisture use efficiency
-Improve
nutrient use efficiency
MANAGEMENT
C
rop rotation
-
Promote plant roots to grow through and break up compacted soils
-
Increase soil organic matter
-
Improve soil structure, improve water infiltration and penetration into soil
-
Promote biological diversity
WHAT IS WATERLOGGING
WATER LOGGING
W
aterlogging refers to the saturation of soil with
water. Soil may be regarded as waterlogged when
the water table of the groundwater is too high to
conveniently permit an anticipated activity, like
agriculture.
WATER LOGGING
ADVANTAGES
P
lanting of WATER LOVING plants.
R
earing of aquaculture
I
rrigation method
DISADVANTAGE
I
nsect harboring
DISADVANTAGE
F
looding
ADVANTAGE
H
inder of Agriculture
DISADVANTAGE
LEACHING
Damaging of plant roots
MANAGEMENT
C
onsider a drainage
C
hoice of crop
F
ertilizer
W
eed control
P
roper farming planning
ACIDIFICATION
SOIL ACIDIFICATIONS
oil acidification is the buildup of hydrogen cations, also called
protons, reducing the soil pH. This happens when a proton donor
is added to the soil. The donor can be an acid, such as nitric acid
and sulfuric acid (these acids are common components of acid
rain). It can also be a compound such as aluminium sulfate, which
reacts in the soil to release protons. Many nitrogen compounds,
which are added as fertilizer, also acidify soil over the long term
because they produce nitrous and nitric acid when oxidized in the
process of nitrification.
SOIL ACIDIFICATION
SYMPTOMS
R
educing Yield
S
tunted root growth
A
bnormal leaf color
P
oor nodulation of legumes
BENEFITS
R
aises soil pH.
A
well balanced soil pH is important for: soil fertility
and nutrient availability plant species that can be
grown biological activity of the soil
BENEFITS
L
ivestock health
I
ncreased calcium and magnesium levels in the plant
helps to overcome problems such as grass tetany in
cattle.
BENEFITS
E
conomics
R
esearch data shows that responses to lime can be
profitable