5.3.1 Climate
The climate controls the necessary needs for the growth and
production of various agricultural crops, the most important
of which in Libya are the light, thermal, and water needs. In
addition to the damage, related to agricultural crops, caused
by the winds, especially the hot and dry ones. The Libyan
climate has already been reviewed in Chap. 3. In the following, there is a special mention of the climatic factors in
terms of their constraint on the growth and production of
agricultural crops. Rain is considered one of the important
climatic factors in areas that depend on rainwater for their
cultivation as the only source of water (such as the rainfed
areas in the Jafara Plain, the Tripoli Mountains, Al Jabal Al
Akhdar, and some northern wadis). The prevailing temperatures in a region are also one of the most important factors
determinants the growth and production of different agricultural crops. These crops vary among themselves in their
ability to withstand temperatures and the extent of their
change. Therefore, only certain crops are able to grow and
produce under different thermal conditions in Libya. Light as
a climatic factor has an essential role in the formation of
chlorophyll, and in the processes of photosynthesis. In
general, the length of the day for agricultural crops is often
the limiting factor for any elongation or shortening of phalanges, and for the formation or non-formation of flowers.
Moreover, plants in light temperate regions (such as in
Libya), grow either acclimatized for a long day or short day
(summer crops compared with winter crops). As a result of
the geographical location of Libya and its presence in areas
in the temperate regions in terms of light, light is not considered a determining factor for agricultural growth and
production.
As for the component of the wind, as previously
explained in Chap. 3, winds of different types and directions
may blow over Libya. Despite the positive effect of these
winds in the formation of clouds, air purification, and the
transfer of pollen and others, the strong winds, especially the
hot dry ones, lead to some physiological, anatomical, and
mechanical damage to agricultural crops, and the wind
becomes one of the main factors that hinder agricultural
crops in places and time its activity.
Relative humidity also affects agricultural crops due to its
effect on the amount and speed of water that is lost through
transpiration and evaporation, the higher the rates of transpiration and evaporation, the higher the water requirements
of crops. From the information contained in Chap. 3, the
relative humidity is high in the northern regions of Libya and
gradually decreases towards the south (The relative humidity
in Jabal Al Akhdar reaches more than 80%, while it reaches
<30% in Al Kufra). Thus, it can be concluded that the water
requirements for a specific crop such as wheat are much
more when it is grown in Al Kufra than when it is grown in
the Al Marj area of the Jabal Al Akhdar (Ben Mahmoud
1995).
5.3.2 Water Resources
Water is the main constraint to agricultural development in
Libya. Water quantity and quality are the main issues related
to the usage of agriculture. Groundwater is the main water
source in Libya. It accounts for more than 88% of the total
water consumption (Salem 1992). The total volume of
groundwater in Libya is estimated to be 99,500 km
3 with an
uncertainty range of between 64,600 and 234,000 km
3
(Fig. 5.4) (MacDonal et al. 2012).
It is clear from Fig. 5.4 that groundwater is the main
source of water for agriculture usage. The majority of this
resource is nonrenewable; thus, in the long term, agriculture
cannot be based on such a resource. Quality and quantity
issues also risk such resources. In the north of the country,
seawater intrusion has affected the coastal areas, whereas in
the south, groundwater resources are not renewable (Ben
Mahmoud 2013). Salem (2007) argued that even if 50% of
the water can be intercepted from rainfall and form a
resource, this 100 million m
3 /yr will constitute only 3% of
water resources. It can be concluded that water resources
mainly depend upon groundwater, and other water resources
are yet to make a considerable contribution to water needs
and demands. This has put a serving pressure on groundwater resources in coastal regions and deserts. This pressure
led to water ground drawdown and seawater intrusion. In the
coastal area, groundwater quality has been badly affected.
The main obstacle to agriculture development is water
resources. Therefore, there is a pressing need to develop
alternative agriculture practices taking this limitation into
Fig. 5.4 Water resources in Libya adapted from (Salem 2007)
70
B. A. Nwer et al.
The climate controls the necessary needs for the growth and
production of various agricultural crops, the most important
of which in Libya are the light, thermal, and water needs. In
addition to the damage, related to agricultural crops, caused
by the winds, especially the hot and dry ones. The Libyan
climate has already been reviewed in Chap. 3. In the following, there is a special mention of the climatic factors in
terms of their constraint on the growth and production of
agricultural crops. Rain is considered one of the important
climatic factors in areas that depend on rainwater for their
cultivation as the only source of water (such as the rainfed
areas in the Jafara Plain, the Tripoli Mountains, Al Jabal Al
Akhdar, and some northern wadis). The prevailing temperatures in a region are also one of the most important factors
determinants the growth and production of different agricultural crops. These crops vary among themselves in their
ability to withstand temperatures and the extent of their
change. Therefore, only certain crops are able to grow and
produce under different thermal conditions in Libya. Light as
a climatic factor has an essential role in the formation of
chlorophyll, and in the processes of photosynthesis. In
general, the length of the day for agricultural crops is often
the limiting factor for any elongation or shortening of phalanges, and for the formation or non-formation of flowers.
Moreover, plants in light temperate regions (such as in
Libya), grow either acclimatized for a long day or short day
(summer crops compared with winter crops). As a result of
the geographical location of Libya and its presence in areas
in the temperate regions in terms of light, light is not considered a determining factor for agricultural growth and
production.
As for the component of the wind, as previously
explained in Chap. 3, winds of different types and directions
may blow over Libya. Despite the positive effect of these
winds in the formation of clouds, air purification, and the
transfer of pollen and others, the strong winds, especially the
hot dry ones, lead to some physiological, anatomical, and
mechanical damage to agricultural crops, and the wind
becomes one of the main factors that hinder agricultural
crops in places and time its activity.
Relative humidity also affects agricultural crops due to its
effect on the amount and speed of water that is lost through
transpiration and evaporation, the higher the rates of transpiration and evaporation, the higher the water requirements
of crops. From the information contained in Chap. 3, the
relative humidity is high in the northern regions of Libya and
gradually decreases towards the south (The relative humidity
in Jabal Al Akhdar reaches more than 80%, while it reaches
<30% in Al Kufra). Thus, it can be concluded that the water
requirements for a specific crop such as wheat are much
more when it is grown in Al Kufra than when it is grown in
the Al Marj area of the Jabal Al Akhdar (Ben Mahmoud
1995).
5.3.2 Water Resources
Water is the main constraint to agricultural development in
Libya. Water quantity and quality are the main issues related
to the usage of agriculture. Groundwater is the main water
source in Libya. It accounts for more than 88% of the total
water consumption (Salem 1992). The total volume of
groundwater in Libya is estimated to be 99,500 km
3 with an
uncertainty range of between 64,600 and 234,000 km
3
(Fig. 5.4) (MacDonal et al. 2012).
It is clear from Fig. 5.4 that groundwater is the main
source of water for agriculture usage. The majority of this
resource is nonrenewable; thus, in the long term, agriculture
cannot be based on such a resource. Quality and quantity
issues also risk such resources. In the north of the country,
seawater intrusion has affected the coastal areas, whereas in
the south, groundwater resources are not renewable (Ben
Mahmoud 2013). Salem (2007) argued that even if 50% of
the water can be intercepted from rainfall and form a
resource, this 100 million m
3 /yr will constitute only 3% of
water resources. It can be concluded that water resources
mainly depend upon groundwater, and other water resources
are yet to make a considerable contribution to water needs
and demands. This has put a serving pressure on groundwater resources in coastal regions and deserts. This pressure
led to water ground drawdown and seawater intrusion. In the
coastal area, groundwater quality has been badly affected.
The main obstacle to agriculture development is water
resources. Therefore, there is a pressing need to develop
alternative agriculture practices taking this limitation into
Fig. 5.4 Water resources in Libya adapted from (Salem 2007)
70
B. A. Nwer et al.