part of Libya) which receives precipitation of more than
200 mm/year and exposed to the Mediterranean and
semi-Mediterranean climates, cover with soils which are
varied in their development according to their soil-forming
factors and processes that exposed to (see Chap. 3). The
difference in soils in these areas actually is due to the
combined effect of soil-forming factors which determined
the activity of specific soil forming process (s), for example,
the Al Jabal Al Akhdar region is semiarid to subhumid
(annual precipitation of 300–600 mm/year), vegetation
cover is forest trees or shrubs, parent materials are calcareous sedimentary rocks, and the terrain is mountainous.
Under these conditions, formation processes called ferrisiallitization are activated accompanied by specific soil
formation processes such as illuviation, dehydration, and
calcification. Consequently, a diagnostic subsurface horizon
(Argillic) of red clay soils is formed (the soil type is called
Xeralfs) (Solkhozprom Export 1980; Ben Mahmoud 1995).
As for the northern areas of western Libya, specifically in
the Jafara Plain, where the parent materials are sandy sediments, the climate is semiarid to arid (annual precipitation of
200–350 mm/year), and the semidesert vegetation is weakly
widespread, the activity of many processes of soil formation
are limited. Therefore, a soil of limited development was
formed which has no diagnostic horizons except for the
surface diagnostic horizon (Ochric), and thus the soil type
spread in these areas are Psamments (Ben Mahmoud 1995).
On the other hand, in the semidesert and desert areas in
southern Libya, where there is a desert climate (annual
precipitation of less than 50 mm/year) and an absence or
scarcity of vegetation cover, soils are only formed in the
desert depressions or old valleys where the water table level
is fairly close to the land surface. Under these conditions, a
number of specific soil formation processes such as Salinization, Solonization, and calcification may occur, forming
only Entisols or Aridisols (Ben Mahmoud 1995).
4.2 Soil Classification Systems Used in Libya
4.2.1 The Russian Soil Classification System
The first soil pedological classification system used in Libya
is the Russian soil classification system (Selkhozpromexport
1980). Soils of 3 million hectares in the northwestern region
and northeastern regions (areas receiving annual precipitation of more than 200 mm/year) were investigated using the
Russian soil classification system. This study was conducted
by the Soil-Ecological Expedition of v/o “Selkhozpromexport”, the Agricultural Research Centre (ARC), University
of Tripoli, and the Ministry of Agriculture. The taxonomy of
the Soviet soil pedology system was used for the elaboration
of the soil classification, and the soil nomenclature generally
applied to characterize the soil mantle of the Mediterranean
countries was also partially used. Classes and subclasses
have been singled out on the basis of the classification
structure for the tropics and subtropics given by Zoon
(1974). The definitions of the Russian terminology system
used are summarized below:
• Class: A class unites soils of similar mineral part composition, the similarity being caused by the nature and
direction of soil formation, as well as by peculiarities of
origin and age of parent materials (weathering crusts).
• Subclass: A subclass unites soil types with similar
combinations of the conditions of their formation connected with the development processes which are conditioned by the composition and properties of the soilforming rock, as well as peculiarities of climatic regimes.
• Type: A type unites soils which develop under similar
(typical) biological, climatic, and hydrological conditions,
and which have a similar soil profile structure, and generally, similar properties. Soils of a single type are characterized by common origin, migration, transformation,
and accumulation of substances. Their genesis is connected with a distinct manifestation of the soil formation
processes, including potential combinations with other
processes.
• Subtype: A subtype embraces soils within a type, varying
in quality as far as the intensity of manifestation of the
main and secondary elementary processes of soil formation is concerned. Subtypes represent stages of an evolutionary transition of one type into another. While
reflecting the peculiarities of soil development, subtypes
preserve a general typical structure of the profile, but, at
the same time, possess some specific features of their
own.
• Genera: A genus includes soil groups within a subtype.
A genus reflects soil properties connected with the
influence of local factors, manifestation of the features
caused by a peculiar character of parent material influence, and chemical composition of groundwater. The
given classification distinguishes soils into genera
according to a combination of their calcareousness,
leachedness, solonetzicity, and salinity, as well as to the
combination of these properties. Table 4.1. and Fig. 4.1
shows the scheme of soil division into classes, types,
subtypes, and genera in northwestern region, while
Table 4.2 and Fig. 4.2 shows classes, types, subtypes in
northeastern region.
50
M. M. Elaalem et al.
200 mm/year and exposed to the Mediterranean and
semi-Mediterranean climates, cover with soils which are
varied in their development according to their soil-forming
factors and processes that exposed to (see Chap. 3). The
difference in soils in these areas actually is due to the
combined effect of soil-forming factors which determined
the activity of specific soil forming process (s), for example,
the Al Jabal Al Akhdar region is semiarid to subhumid
(annual precipitation of 300–600 mm/year), vegetation
cover is forest trees or shrubs, parent materials are calcareous sedimentary rocks, and the terrain is mountainous.
Under these conditions, formation processes called ferrisiallitization are activated accompanied by specific soil
formation processes such as illuviation, dehydration, and
calcification. Consequently, a diagnostic subsurface horizon
(Argillic) of red clay soils is formed (the soil type is called
Xeralfs) (Solkhozprom Export 1980; Ben Mahmoud 1995).
As for the northern areas of western Libya, specifically in
the Jafara Plain, where the parent materials are sandy sediments, the climate is semiarid to arid (annual precipitation of
200–350 mm/year), and the semidesert vegetation is weakly
widespread, the activity of many processes of soil formation
are limited. Therefore, a soil of limited development was
formed which has no diagnostic horizons except for the
surface diagnostic horizon (Ochric), and thus the soil type
spread in these areas are Psamments (Ben Mahmoud 1995).
On the other hand, in the semidesert and desert areas in
southern Libya, where there is a desert climate (annual
precipitation of less than 50 mm/year) and an absence or
scarcity of vegetation cover, soils are only formed in the
desert depressions or old valleys where the water table level
is fairly close to the land surface. Under these conditions, a
number of specific soil formation processes such as Salinization, Solonization, and calcification may occur, forming
only Entisols or Aridisols (Ben Mahmoud 1995).
4.2 Soil Classification Systems Used in Libya
4.2.1 The Russian Soil Classification System
The first soil pedological classification system used in Libya
is the Russian soil classification system (Selkhozpromexport
1980). Soils of 3 million hectares in the northwestern region
and northeastern regions (areas receiving annual precipitation of more than 200 mm/year) were investigated using the
Russian soil classification system. This study was conducted
by the Soil-Ecological Expedition of v/o “Selkhozpromexport”, the Agricultural Research Centre (ARC), University
of Tripoli, and the Ministry of Agriculture. The taxonomy of
the Soviet soil pedology system was used for the elaboration
of the soil classification, and the soil nomenclature generally
applied to characterize the soil mantle of the Mediterranean
countries was also partially used. Classes and subclasses
have been singled out on the basis of the classification
structure for the tropics and subtropics given by Zoon
(1974). The definitions of the Russian terminology system
used are summarized below:
• Class: A class unites soils of similar mineral part composition, the similarity being caused by the nature and
direction of soil formation, as well as by peculiarities of
origin and age of parent materials (weathering crusts).
• Subclass: A subclass unites soil types with similar
combinations of the conditions of their formation connected with the development processes which are conditioned by the composition and properties of the soilforming rock, as well as peculiarities of climatic regimes.
• Type: A type unites soils which develop under similar
(typical) biological, climatic, and hydrological conditions,
and which have a similar soil profile structure, and generally, similar properties. Soils of a single type are characterized by common origin, migration, transformation,
and accumulation of substances. Their genesis is connected with a distinct manifestation of the soil formation
processes, including potential combinations with other
processes.
• Subtype: A subtype embraces soils within a type, varying
in quality as far as the intensity of manifestation of the
main and secondary elementary processes of soil formation is concerned. Subtypes represent stages of an evolutionary transition of one type into another. While
reflecting the peculiarities of soil development, subtypes
preserve a general typical structure of the profile, but, at
the same time, possess some specific features of their
own.
• Genera: A genus includes soil groups within a subtype.
A genus reflects soil properties connected with the
influence of local factors, manifestation of the features
caused by a peculiar character of parent material influence, and chemical composition of groundwater. The
given classification distinguishes soils into genera
according to a combination of their calcareousness,
leachedness, solonetzicity, and salinity, as well as to the
combination of these properties. Table 4.1. and Fig. 4.1
shows the scheme of soil division into classes, types,
subtypes, and genera in northwestern region, while
Table 4.2 and Fig. 4.2 shows classes, types, subtypes in
northeastern region.
50
M. M. Elaalem et al.