process and it generally takes several thousand years for
significant changes to take place. Younger soils have some
properties from their parent materials, but with age, the
addition of organic matter, exposure to moisture, and other
environmental factors, their features may be altered. The
degree of aging depends on the intensity of other soil
forming factors. Factors that slow soil formation include
high lime content, high quartz content, or high clay content
in parent material, hard rock parent material (resistant to
weathering), low rainfall, low humidity, cold temperature,
steep slopes, high water table, severe erosion, constant
deposition, accumulations, and mixing by animals or man
(Lamb and George 2018).
3.3 Processes of Soil Formation
In general, it is known that (mineral) soils form from the
solid rocks of the earth’s crust through a set of processes
called soil formation processes. The process of soil formation is very complex and includes many overlapping processes. At any given geographical location, soil formation
factors operate collectively to create ideal formation conditions. Controlled by the dominion and effectiveness of one or
more soil formation processes, a particular type of soil is
formed under these conditions (Ben Mahmoud 1995). As
previously explained in Sect. 3.2 of this chapter, the factors
of soil formation in Libya are mainly influenced by a hot and
dry climate (low and irregular rainfall, high temperature,
with a wide range of daily and seasonal temperature fluctuations, and strong wind speed). Thus, this climate dependency dictates particular types of soil formation processes
that are more dominant in Libya and reduce, if not eliminate,
the effectiveness of many of them.
3.3.1 Weathering Processes
Weathering processes are responsible for forming soil parent
materials from the bedrocks. It is a group of processes that
lead to changes in the natural state and chemical components
of the rocks. It is basically a mixture of demolition and
construction activities. With weathering, rock is disintegrated into smaller pieces (getting smaller and smaller) until
they eventually reach the individual minerals from which
they are formed.
3.3.1.1 Physical Weathering Processes
Physical weathering, also called Mechanical weathering,
breaks rock into smaller pieces. These smaller pieces are just
like the bigger rock, only differing in size. This means that
the rock has changed physically without changing its
chemical composition and crystalline form. The smaller
pieces have the same minerals in just the same proportions
as the original rock. These processes are among the most
important processes that form the parent materials of the
Libyan soils, especially in the western, central, and southern
regions. The following are the most important physical
weathering processes in Libya (Ben Mahmoud 1995):
• Daily and seasonal temperature fluctuations: The
fluctuations of the daily and seasonal temperature lead to
inconsistent fragmentation of rocks into uneven large
portions, due to the difference in the thermal expansion
coefficients of its minerals. This process is more effective
in the southern desert regions (desert areas).
• Erosion: Erosion is the action of surface processes (such
as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth’s crust and
then transports it to another location (Sriwati et al. 2018).
In Libya, wind deposits (sand and silt) are considered one
of the most important parent materials of the Libyan soils
that commonly widespread across the country.
• The mechanical action of sea waves: This process is
responsible for breaking up the rocks on the seabed.
When the waves are high, sea waves throw these products
on the beaches, forming marine parent materials or
coastal sand.
3.3.1.2 Chemical Weathering Processes
Chemical weathering processes are considerably more varied
and complex. They include simple solution, hydrolysis,
hydration, and oxidation-reduction. These processes involve
the alteration of the chemical and mineralogical composition
of the weathered material which leads to the formation of new
minerals. Water is the main determining factor for these
processes, wherein its absence, the other essential factors for
chemical reactions such as heat, gases, and microorganisms
on their own seem incapable of playing any role. Therefore,
the chemical weathering processes are more active in the
regions that are exposed to a sufficient amount of rainfall.
Thus, the impact of chemical weathering processes during the
formation of the parent material in Libya is limited to areas
that receive precipitation rates of more than 200 mm/year.
These areas are located in Al Jabal Al Akhdar, the Tripoli
Mountains, and some coastal areas (Ben Mahmoud 1995).
3.4 Soil Forming Processes
Soil forming processes are reflected in the different horizons
developed within the soil profile. These processes can be
limited to two main groups: specific processes of soil formation, and composite processes of soil formation. The
following is a review of some of these processes that are
specifically predominant in Libya (Ben Mahmoud 1995):
3 Soil Forming Factors and Processes
43
significant changes to take place. Younger soils have some
properties from their parent materials, but with age, the
addition of organic matter, exposure to moisture, and other
environmental factors, their features may be altered. The
degree of aging depends on the intensity of other soil
forming factors. Factors that slow soil formation include
high lime content, high quartz content, or high clay content
in parent material, hard rock parent material (resistant to
weathering), low rainfall, low humidity, cold temperature,
steep slopes, high water table, severe erosion, constant
deposition, accumulations, and mixing by animals or man
(Lamb and George 2018).
3.3 Processes of Soil Formation
In general, it is known that (mineral) soils form from the
solid rocks of the earth’s crust through a set of processes
called soil formation processes. The process of soil formation is very complex and includes many overlapping processes. At any given geographical location, soil formation
factors operate collectively to create ideal formation conditions. Controlled by the dominion and effectiveness of one or
more soil formation processes, a particular type of soil is
formed under these conditions (Ben Mahmoud 1995). As
previously explained in Sect. 3.2 of this chapter, the factors
of soil formation in Libya are mainly influenced by a hot and
dry climate (low and irregular rainfall, high temperature,
with a wide range of daily and seasonal temperature fluctuations, and strong wind speed). Thus, this climate dependency dictates particular types of soil formation processes
that are more dominant in Libya and reduce, if not eliminate,
the effectiveness of many of them.
3.3.1 Weathering Processes
Weathering processes are responsible for forming soil parent
materials from the bedrocks. It is a group of processes that
lead to changes in the natural state and chemical components
of the rocks. It is basically a mixture of demolition and
construction activities. With weathering, rock is disintegrated into smaller pieces (getting smaller and smaller) until
they eventually reach the individual minerals from which
they are formed.
3.3.1.1 Physical Weathering Processes
Physical weathering, also called Mechanical weathering,
breaks rock into smaller pieces. These smaller pieces are just
like the bigger rock, only differing in size. This means that
the rock has changed physically without changing its
chemical composition and crystalline form. The smaller
pieces have the same minerals in just the same proportions
as the original rock. These processes are among the most
important processes that form the parent materials of the
Libyan soils, especially in the western, central, and southern
regions. The following are the most important physical
weathering processes in Libya (Ben Mahmoud 1995):
• Daily and seasonal temperature fluctuations: The
fluctuations of the daily and seasonal temperature lead to
inconsistent fragmentation of rocks into uneven large
portions, due to the difference in the thermal expansion
coefficients of its minerals. This process is more effective
in the southern desert regions (desert areas).
• Erosion: Erosion is the action of surface processes (such
as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth’s crust and
then transports it to another location (Sriwati et al. 2018).
In Libya, wind deposits (sand and silt) are considered one
of the most important parent materials of the Libyan soils
that commonly widespread across the country.
• The mechanical action of sea waves: This process is
responsible for breaking up the rocks on the seabed.
When the waves are high, sea waves throw these products
on the beaches, forming marine parent materials or
coastal sand.
3.3.1.2 Chemical Weathering Processes
Chemical weathering processes are considerably more varied
and complex. They include simple solution, hydrolysis,
hydration, and oxidation-reduction. These processes involve
the alteration of the chemical and mineralogical composition
of the weathered material which leads to the formation of new
minerals. Water is the main determining factor for these
processes, wherein its absence, the other essential factors for
chemical reactions such as heat, gases, and microorganisms
on their own seem incapable of playing any role. Therefore,
the chemical weathering processes are more active in the
regions that are exposed to a sufficient amount of rainfall.
Thus, the impact of chemical weathering processes during the
formation of the parent material in Libya is limited to areas
that receive precipitation rates of more than 200 mm/year.
These areas are located in Al Jabal Al Akhdar, the Tripoli
Mountains, and some coastal areas (Ben Mahmoud 1995).
3.4 Soil Forming Processes
Soil forming processes are reflected in the different horizons
developed within the soil profile. These processes can be
limited to two main groups: specific processes of soil formation, and composite processes of soil formation. The
following is a review of some of these processes that are
specifically predominant in Libya (Ben Mahmoud 1995):
3 Soil Forming Factors and Processes
43