ChapterPDF Available

Soil Salinity: Historical Perspectives and a World Overview of the Problem

Authors:
  • Environment and Life Sciences Research Center Kuwait Institute for Scientific Research Kuwait

Abstract and Figures

Soil salinity is not a recent phenomenon, it has been reported since centuries where humanity and salinity have lived one aside the other. A good example is from Mesopotamia where the early civilizations first flourished and then failed due to human-induced salinization. A publication ‘Salt and silt in ancient Mesopotamian agriculture’ highlights the history of salinization in Mesopotamia where three episodes (earliest and most serious one affected Southern Iraq from 2400 BC until at least 1700 BC, a milder episode in Central Iraq occurred between 1200 and 900 BC, and the east of Baghdad, became salinized after 1200 AD) have been reported. There are reports clearly revealing that ‘many societies based on irrigated agriculture have failed’, e.g. Mesopotamia and the Viru valley of Peru. The flooding, over-irrigation, seepage, silting, and a rising water table have been reported the main causes of soil salinization. Recent statistics of global extent of soil salinization do not exist, however, various scientists reported extent differently based on different data sources, such as there have been reports like, 10% of the total arable land as being affected by salinity and sodicity, one billion hectares are covered with saline and/or sodic soils, and between 25% and 30% of irrigated lands are salt-affected and essentially commercially unproductive, global distribution of salt-affected soils are 954 million ha, FAO in 1988 presented 932 million ha salt-affected soils, of almost 1500 million ha of dryland agriculture, 32 million ha are salt-affected. Precise information on the recent estimates of global extent of salt-affected soils do not exist, many countries have assessed their soils and soil salinization at the national level, such as Kuwait, United Arab Emirates, Middle East, and Australia etc. Considering the current extent of salt-affected soils the cost of salt-induced land degradation in 2013 was $441 per hectare, a simple benefit transfer suggests the current annual economic losses could be $27 billion.
Content may be subject to copyright.
Chapter 2
Soil Salinity: Historical Perspectives
and a World Overview of the Problem
Abstract Soil salinity is not a recent phenomenon, it has been reported since
centuries where humanity and salinity have lived one aside the other. A good example
is from Mesopotamia where the early civilizations rst ourished and then failed due
to human-induced salinization. A publication Salt and silt in ancient Mesopotamian
agriculturehighlights the history of salinization in Mesopotamia where three epi-
sodes (earliest and most serious one affected Southern Iraq from 2400 BC until at least
1700 BC, a milder episode in Central Iraq occurred between 1200 and 900 BC, and the
east of Baghdad, became salinized after 1200 AD) have been reported. There are
reports clearly revealing that many societies based on irrigated agriculture have
failed, e.g. Mesopotamia and the Viru valley of Peru. The ooding, over-irrigation,
seepage, silting, and a rising water table have been reported the main causes of soil
salinization. Recent statistics of global extent of soil salinization do not exist, however,
various scientists reported extent differently based on different data sources, such as
there have been reports like, 10% of the total arable land as being affected by salinity
and sodicity, one billion hectares are covered with saline and/or sodic soils, and
between 25% and 30% of irrigated lands are salt-affected and essentially commercially
unproductive, global distribution of salt-affected soils are 954 million ha, FAO in 1988
presented 932 million ha salt-affected soils, of almost 1500 million ha of dryland
agriculture, 32 million ha are salt-affected. Precise information on the recent estimates
of global extent of salt-affected soils do not exist, many countries have assessed their
soils and soil salinization at the national level, such as Kuwait, United Arab Emirates,
Middle East, and Australia etc. Considering the current extent of salt-affected soils the
cost of salt-induced land degradation in 2013 was $441 per hectare, a simple benet
transfer suggests the current annual economic losses could be $27 billion.
Keywords Historical perspective · Mesopotamia · Iraq · Global extent · Economic
losses · Viru valley
Shabbir A. Shahid, Mohammad Zaman, and Lee Heng
©International Atomic Energy Agency 2018
M. Zaman et al., Guideline for Salinity Assessment, Mitigation and Adaptation Using
Nuclear and Related Techniques,https://doi.org/10.1007/978-3-319-96190-3_2
43
1 Introduction
Soil salinity is a major global issue owing to its adverse impact on agricultural
productivity and sustainability. Salinity problems occur under all climatic conditions
and can result from both natural and human-induced actions. Generally speaking,
saline soils occur in arid and semi-arid regions where rainfall is insufcient to meet
the water requirements of the crops, and leach mineral salts out of the root-zone. The
association between humans and salinity has existed for centuries and historical
records show that many civilizations have failed due to increases in the salinity of
agricultural elds, the most known example being Mesopotamia (now Iraq). Soil
salinity undermines the resource base by decreasing soil quality and can occur due to
natural causes or from misuse and mismanagement to an extent which jeopardizes
the integrity of soils self-regulatory capacity.
Soil salinity is dynamic and spreading globally in over 100 countries; no conti-
nent is completely free from salinity (Fig. 2.1). Soil salinization is projected to
increase in future climate change scenarios due to sea level rise and impact on
coastal areas, and the rise in temperature that will inevitably lead to increase
evaporation and further salinization. Salinization of soils can affect ecosystems to
an extent where they no longer can provide environmental servicesto their full
potential. It is realized that recent estimates of the global extent of soil salinization do
not exist. But it can be assumed that, since the earlier data gathering in the 1970s and
1980s, salinization has expanded as newly affected areas most probably exceed the
areas restored through reclamation and rehabilitation. There is a long list of countries
where salt-induced land degradation occurs. Some well-known regions where sali-
nization is extensively reported include the Aral Sea Basin (Amu-Darya and
Syr-Darya River Basins) in Central Asia, the Indo-Gangetic Basin in India, the
Fig. 2.1 World map representing countries with salinity problems. (https://www.researchgate.net/
publication/262495450)
44 2 Soil Salinity: Historical Perspectives and a World Overview of the Problem
Indus Basin in Pakistan, the Yellow River Basin in China, the Euphrates Basin in
Syria and Iraq, the Murray-Darling Basin in Australia, and the San Joaquin Valley in
the United States (Qadir et al. 2014).
2 Soil Salinity A Historical and Contemporary
Perspective
For centuries, humanity and salinity have lived one aside the other. There is good
evidence for Mesopotamia that early civilizations ourished and then failed due to
human-induced salinization. Jacobson and Adams (1958), in their publication, Salt
and silt in ancient Mesopotamian agriculturehighlighted the history of salinization
in Mesopotamia. Ancient records show three episodes of soil salinization in Iraq.
The earliest and the most serious one affected Southern Iraq from 2400 BC until at
least 1700 BC. A milder episode in Central Iraq occurred between1200 BC and
900 BC, and there is archeological evidence that the Nahrwan area, east of Baghdad,
became salinized after 1200 AD. Flooding, over-irrigation, seepage, silting, and a
rising water-table are considered to be the main reasons for these episodes of
increased salinization (Gelburd 1985).
In southern Iraq in 3500 BC, both wheat and barley were equally important
cultivated crops, though after 100 years wheat had slipped to one sixth, and by
2100 BC, its cultivation had become almost insignicant, dropping to only 2%. By
1700 BC, wheat cultivation was completely phased out. Historical records show that
concurrent with the shift to barley cultivation, there was an appreciable and serious
decline in soil fertility and gradual declines in barley yields, which for the most part
can be attributed to salinization (Jacobson and Adams 1958). Thus, after almost
5000 years of successful irrigated agriculture, the Sumerian civilization failed. In the
Indus plains of Pakistan and India, the practice of irrigation began about 2000 years
ago during the Harapa civilization, but it is only recently that serious problems of
salinity and sodicity are being encountered. In the Viru valley of Peru, irrigated
agriculture began between 800 BC and 30 AD (Wiley 1953), and by 800 AD, the
population was at a peak. Then from 1200 AD, the population declined appreciably
and the residents of the once densely populated Viru valley bottom relocated to more
narrow upper reaches of the valley. The historians partly attribute this relocation to
increased salinity and a rising water- table, together with inadequate soil drainage
(Armillas 1961). Tanji (1990) draws a historical perspective of irrigation-induced
salinity in several regions. In a similar perspective, general remarks by Wiley (1953)
clearly reveal that many societies based on irrigated agriculture have failed,
e.g. Mesopotamia and the Viru valley of Peru.
2 Soil Salinity A Historical and Contemporary Perspective 45
3 An Overview of Salinity Problem
The earths land surface is 13.2 10
9
ha, but only 7 10
9
ha of this is arable, of
which only 1.5 10
9
ha is currently cultivated (Massoud 1981). Of the cultivated
lands, about 0.34 10
9
ha (23%) are saline and 0.56 10
9
ha (37%) are sodic.
Older estimates (Szabolcs 1989) described 10% of the total arable land as being
affected by salinity and sodicity, with the effects extending to over 100 countries in
all continents. One billion hectares of the 13.2 10
9
hectares of the land is, thus,
covered with saline and/or sodic soils, and between 25% and 30% of irrigated lands
are salt-affected and essentially commercially unproductive.
The countries affected by salinization are predominantly located in arid and semi-
arid regions, where continued irrigation with low quality groundwater has taken
place. Low rainfall has also contributed to the expansion of salt-affected soils. The
largest area of the worlds saline soils occurs in the arid and semi-arid regions
(Massoud 1974; Ponnamperuma 1984), where evapotranspiration exceeds precipi-
tation. The rapid conversion into barren land through salinity/sodicity has negatively
affected the environment and has substantially altered natural resources in a number
of countries. Worldwide, some ten million hectares of irrigated land is abandoned
annually because of salinization, sodication and waterlogging (Szabolcs 1989).
These degraded soils occur principally in the hot arid and semi-arid regions,
although they have also been recorded in Polar Regions (Buringh 1979).
Global statistics on salt-affected soils vary according to different data sources.
Saline soils occupied more than 20% of the worlds irrigated area by the mid-1990s
(Ghassemi et al. 1995). Since then, the extent of salinity has likely increased and, in
some countries, salt-affected soils occur on more than half of the irrigated lands
(Metternicht and Zinck 2003). Kovda and Szabolcs (1979) reported global distribu-
tion of salt-affected soils as 954 million ha. Data summarized from Szabolcs (1974)
for Europe and Massoud (1977) for the other continents, as reported by Abrol et al.
(1988) in FAO Soils Bulletin 39, presents 932.2 million ha of salt-affected soils
(Table 2.1). Of almost 1500 million ha of dryland agriculture, 32 million ha are salt-
affected (FAO 2000). Although recent estimates of global extent of salt-affected
soils do not exist, many countries have assessed their soils and soil salinization levels
at the national level, such as Kuwait (Shahid et al. 2002), United Arab Emirates
Table 2.1 Worldwide
distribution of salt-affected
areas (Million ha)
Area Saline soils Sodic soils Total Percent
Australasia 17.6 340.0 357.6 38.4
Asia 194.7 121.9 316.5 33.9
America 77.6 69.3 146.9 15.8
Africa 53.5 26.9 80.4 8.60
Europe 7.8 22.9 30.8 3.30
World 351.2 581.0 932.2 100
Source:Abrol et al. (1988) in FAO Soil Bulletin 39; Summary of
data for Europe (Szabolcs 1974) and for other continents
(Massoud 1977)
46 2 Soil Salinity: Historical Perspectives and a World Overview of the Problem
(EAD 2009,2012), Middle East (Hussein 2001; Shahid et al. 2010), and Australia
(Oldeman et al. 1991).
In a comprehensive overview of the global identication of salinity problems and
the global salinity status, Shahid (2013) reported that about 200 10
6
hectares of
land is affected by salinity in Southwest USA and Mexico. In Spain, Portugal,
Greece, and Italy, saltwater intrusion into aquifers is appreciable; in Spain more
than 20% of the land area is desert, or is seriously degraded and, thus,
nonproductive.
In the Middle East, 20 10
6
hectares are affected by increased soil salinity, the
reasons being poor irrigation practices, high evaporation rates, growth of sabkhas
(salt scalds), and an increase in groundwater salinity. In addition, productivity of the
irrigated lands of the Euphrates basin (Syria, Iraq) is seriously constrained by
salinity. In Iran, 14.2% of the total land area is salt-affected (Pazira 1999). In
Egypt, 1 10
6
hectares of land which could be cultivated along the Nile is salt-
affected. Salt accumulation in the Jordan River basin adversely affects agricultural
production in Syria and Jordan. In Africa, 80 10
6
hectares is saline, sodic, or
saline-sodic, of which the Sahel, in West Africa, is the most affected.
In Asia, 20% of Indias cultivable land, mainly in Rajasthan, coastal Gujarat, and
the Indo-Gangetic plains, is affected by salinity or sodicity. In Pakistan, 10 10
6
hectares is affected and about 510 hectares per hour is lost to salinity and/or
waterlogging in coastal regions and in the irrigated Indus basin. In Bangladesh,
310
6
hectares is unproductive due to salinity. In Thailand, 3.58 10
6
hectares is
salt-affected (3.0 10
6
hectares being inland and 0.58 10
6
hectares being coastal
saline soils). In China, 26 10
6
hectares of their total land area is salt-affected (Inner
Mongolia, the Yellow River basin and tidal coastal regions), while in Australia the
extent of saline soils is 357 10
6
hectares.
The global extent and distribution of 76.6 million hectares of human-induced salt-
affected soils (Oldeman et al. 1991) and a similar distribution for irrigated lands
affected by secondary salinization (Ghassemi et al. 1995) are presented in Tables 2.2
and 2.3. These soils are distributed in desert and semi-desert regions, frequently
occurring in fertile alluvial plains, river valleys, coastal areas and in irrigation
districts. The countries where signicant salinity problems exist include, but are
not limited, to Australia, China, Egypt, India, Iran, Iraq, Mexico, Pakistan, the
Table 2.2 Global extent of human-induced salinization (Oldeman et al. 1991; Mashali 1995)
Continent
Degree of salinization and affected area (mha)
Percent
Light Moderate Strong Extreme Total
Africa 4.7 7.7 2.4 14.8 19.3
Asia 26.8 8.5 17.0 0.4 52.7 68.8
South America 1.8 0.3 –– 2.1 2.7
North & central America 0.3 1.5 0.5 2.3 3.0
Europe 1.0 2.3 0.5 3.8 5.0
Australia 0.5 0.4 0.9 1.2
World total 34.6 20.8 20.4 0.8 76.6 100
3 An Overview of Salinity Problem 47
USSR, Syria, Turkey, and the United States. In Gulf States (Bahrain, Kuwait, Saudi
Arabia, Qatar, Oman, and the United Arab Emirates), saline soils mainly occur in
coastal lands (due to seawater intrusion), and also on agricultural farms irrigated with
saline/brackish water.
Secondary salinization (i.e., soil salinization due to human activities such as
irrigated agriculture) is predominantly located in the arid and semi-arid regions
including Egypt, Iran, Iraq, India, China, Chile, Argentina, Commonwealth of
Independent States, Spain, Thailand, Pakistan, Syria, Turkey, Algeria, Tunisia,
Sudan and the Gulf States. About 76.6 million hectares (Table 2.2) of cultivated
lands are salt-affected by human-induced processes (Oldeman et al. 1991; Mashali
1995; Ghassemi et al. 1995) and approximately 30 million ha can be attributed to
secondary salinization of non-irrigated lands. However, according to Ghassemi et al.
(1995), globally 20% or 45 million hectares out of a total 227 million hectares of
irrigated land are salt-affected (Table 2.3).
4 Distribution of Salinity in Drylands in Different
Continents of the World
As reported by UNEP (1992), the distribution of salt-affected soils in drylands in
different continents is presented in Table 2.4. These soils are divided into two
categories: saline (412 million hectares) and sodic (618 million hectares), totaling
1030 million hectares. Australasia has the widest distribution with 357.6 million
hectares, followed by Africa with 209.6 million hectares.
Table 2.3 Global estimates of secondary salinization in the worlds irrigated lands. (Summarized
from Ghassemi et al. 1995; Mashali 1995)
Country
Area (mha)
Cropped Irrigated Salt-affected
a
China 97.0 44.8 6.7 (15)
India 169.0 42.1 7.0 (17)
Commonwealth of independent states 232.5 20.5 3.7 (18)
United States of America 190.0 18.1 4.2 (23)
Pakistan 20.8 16.1 4.2 (26)
Iran 14.8 5.8 1.7 (29)
Thailand 20.0 4.0 0.4 (10)
Egypt 2.7 2.7 0.9 (33)
Australia 47.1 1.8 0.2 (11)
Argentina 35.8 1.7 0.6 (35)
South Africa 13.2 1.1 0.1 (9)
Subtotal 842.9 158.7 29.7 (19)
World (Total) 1474 227 45 (20)
a
Salt-affected soils within the irrigated area; values in parentheses are percentage
48 2 Soil Salinity: Historical Perspectives and a World Overview of the Problem
5 Irrigation Practices and Soil Salinization
The practice of irrigation, if not planned and managed properly, can result in
increased soil salinization. An estimate (Postel 1989) shows that about 25% of the
worlds irrigated lands are damaged by salinity, while Adams and Hughes (1990)
have reported that up to 50% of irrigated lands are affected by salt. Szabolcs (1989)
states that no continent is free from salt-affected soils and serious salt-related
problems occur in at least 70 countries. Table 2.5 shows the area of irrigated land
damaged by salinization for the ve worst-affected countries (Postel 1989).
6 Regional Overview of Salinity Problem
More recent estimates of the regional distribution of saline soils do not exist. There is
a need to update this information in order to better understand the extent of the
problem and to develop soil use and management policies. Such estimates are
essential given the continuing decline of soil resources for food production. An
earlier search of the literature (Mashali 1995; FAO-Unesco Soil map of the world
Table 2.4 Salt-affected soils in drylands by continents (UNEP 1992; cf FAO-ITPS-GSP 2015)
Continent
Salt-affected area (mha)
Saline soils Sodic soils Total
Africa 122.9 86.7 209.6
Australasia 17.6 340.0 357.6
Mexico/Central America 2.0 2.0
North America 6.2 9.6 15.8
North and Central Asia 91.5 120.2 211.7
South America 69.5 59.8 129.3
South Asia 82.3 1.8 84.1
Southeast Asia 20.0 20.0
Total 412.0 618.1 1030.1
Table 2.5 Soil salinity
caused by irrigation in major
irrigating countries and in the
world (Postel 1989)
Country
Area damaged
mha % of irrigated land
India 20.0 36.0
China 7.0 15.0
United States of America 5.2 27.0
Pakistan 3.2 20.0
Soviet Union 2.5 12.0
Total 37.9 24.0
World 60.2 24.0
6 Regional Overview of Salinity Problem 49
1974) does, however, give an estimate of the extent of the regional distribution of
salt-affected soils (Table 2.6). These estimates show the total extent to be 932 million
hectares of salt-affected lands, with the maximum area occurring in the region of
Australasia (357 million ha).
7 Extent of Soil Salinity in the Middle East
Information regarding the extent of salinization in the Middle East is very limited.
However, some general information has been obtained through the use of Remote
Sensing imagery and other methods. This information was used to develop a soil
salinization map of the Middle East (Hussein 2001; Shahid et al. 2010). In this map,
salinization was divided into four general categories: slight, moderate, severe and
very severe, as shown in Table 2.7. Earlier, an estimated area of 209,000 hectares has
been reported as being salinized in Kuwait (Hamdallah 1997), which is roughly 3%
of the total Kuwait land area.
Table 2.7 shows an area of 11.2% of the Middle East being affected to varying
levels by soil salinization. Realizing the soil salinity, a hazard to agriculture and to
the ecosystem services, Shahid et al. (1998) described soil salinization as early
warning of land degradation in Kuwait. Later, Shahid et al. (2002) interpreted the
soil survey data (KISR 1999) using GIS and mapped soil salinity into different
salinity zones, where area occupied by each zone is as: 4.1 10 dS m
1
(0.685%),
10.1 25.0 dS m
1
(4.37%), and more than 25 dS m
1
(7.06%). This concludes an
area of about 12.1% affected to varying degrees of salinity in the entire state of
Kuwait. In the Abu Dhabi Emirate (EAD 2009), an area of 35.5% (2,034,000 ha) has
been depicted to be affected to varying degrees of soil salinity. The highly saline
soils on the soil salinity map are conned to the coastal land (King et al. 2013), the
areas of deation plains, and inland sabkha (salt scald) where the groundwater levels
approach the surface, creating large areas of aquisalids at the great group level of US
soil taxonomy (Soil Survey Staff 2014; Shahid et al. 2014).
Table 2.6 Regional distribution of salt-affected soils (mha). (cf.Mashali 1995)
Region Solonchak saline phase Solonetz sodic phase Total
North America 6 10 16
Mexico and Central America 2 2
South America 69 60 129
Africa 54 27 81
South and West Asia 83 2 85
South East Asia 20 20
North and Central Asia 92 120 212
Australasia 17 340 357
Europe 9 21 30
Total 352 580 932
50 2 Soil Salinity: Historical Perspectives and a World Overview of the Problem
8 Socioeconomic Aspects of Soil Salinization
A comprehensive review of published literature revealed very few publications
dealing with socioeconomic aspects of salt-induced land degradation. On the global
level, generation of such information requires appreciable resources and the com-
mitment of properly trained staff to the project. However, Qadir et al. (2014)
conclude that previous studies show a limited number of highly variable estimates
of the costs of salt-induced land degradation. Even so, they have made simple
extrapolations from these studies and the estimates show that the global annual
cost of salt-induced land degradation in irrigated areas could be US$ 27.3 billion in
lost crop production. Based on these estimates, Qadir et al. (2014) recommended
investing in the remediation of salt-affected lands and noted that remediation costs
must be included in a broader national strategy for food security, and dened in
national action plans.
Qadir et al. (2014) identied countries where such economic cost on salt-induced
soil degradation has been reported, including but not necessarily limited to Australia,
India, the United States, Iraq, Pakistan, Kazakhstan, Uzbekistan, and Spain. They
further indicated that the valuation of the cost of salt-induced land degradation has
been mainly based on estimates of crop production losses. However, it is unclear
whether their comparisons are made with crop production values taken from land not
affected by salinity.
Taking the above examples into account, Qadir et al. (2014) have concluded that,
considering the current extent of global irrigated area 310 million hectares
(FAO-AQUASTAT 2013) and 20% of this area as salt-affected (62 million hect-
ares), and the ination-adjusted cost of salt-induced land degradation in 2013 as US$
441 per hectare, a simple benet transfer suggests the current annual economic
losses could be US$ 27.3 billion.
References
Abrol IP, Yadav JSP, Massoud FI (1988) Salt-affected soils and their management. FAO Soils
Bulletin 39, Food and Agriculture Organization of the United Nations, Rome, Italy, 131 pp
Adams WM, Hughes FMR (1990) Irrigation development in desert environments. In: Goudi AS
(ed) Techniques for desert reclamation. Wiley, New York, pp 135160
Armillas P (1961) Land use in pre-Columbian America. In: Stamp LD (ed) A history of land use in
arid regions, vol 17. UNESCO Arid Zone Research, Paris, pp 255276
Table 2.7 Salinization
classes and affected area in the
Middle East (Hussein 2001;
Shahid et al. 2010)
Class Area km
2
Area %
Slight 113,814 1.72
Moderate 109,148 1.65
Severe 380,025 5.74
Very severe 138,204 2.09
Total 741,191 11.2
References 51
Buringh P (ed) (1979) Introduction to the soils of tropical and subtropical regions, 3rd edn. Center
for Agricultural Publishing and Documentation, Wageningen, 124 pp
EAD (2009) Soil survey for the emirate of Abu Dhabi. Reconnaissance soil survey report. Volume
1. Environment Agency Abu Dhabi, United Arab Emirates
EAD (2012) Soil survey of northern emirates. Environment Agency Abu Dhabi, 2 Volumes
FAO (2000) Extent and causes of salt-affected soils in participating countries. Global network on
integrated soil management for sustainable use of salt-affected soils. FAO-AGL website
FAO-AQUASTAT (2013) Area equipped for irrigation and percentage of cultivated land. Available
at http://www.fao.org/nr/water/aquastat/globalmaps/index.stm. Accessed 16 Sept 2013
FAO-ITPS-GSP (2015) Status of the worlds soil resources. FAO-ITPS-GSP Main Report, Food
and Agriculture Organization of the United Nations, Rome, Italy, pp 125127
FAO-UNESCO (1974) FAO-Unesco soil map of the world. 1:5 000 000, UNESCO Paris,
10 volumes
Gelburd DE (1985) Managing salinity lessons from the past. J Soil Water Conserv 40(4):329331
Ghassemi F, Jakeman AJ, Nix HA (1995) Salinisation of land and water resources: human causes,
extent, management and case studies. CABI Publishing, Wallingford, 526 pp
Hamdallah G (1997) An overview of the salinity status of the near east region. Proceedings of the
workshop on management of salt-affected soils in the Arab Gulf States, Abu Dhabi, United Arab
Emirates, 29 October2 November 1995. Food and Agriculture Organization of the United
Nations, Regional Ofce for the Near East, Cairo, Egypt, pp 15
Hussein H (2001) Development of environmental GIS database and its application to desertication
study in Middle East a remote sensing and GIS application. PhD thesis Graduate School of
Science and Technology, Chiba University Japan, 155 pp
Jacobson T, Adams RM (1958) Salt and silt in ancient Mesopotamian agriculture. Science (New
Series) 128(3334):12511258
King P, Grealish G, Shahid SA, Abdelfattah MA (2013) Land evaluation interpretations and
decision support systems: soil survey of Abu Dhabi emirate. Chapter 6. In: Shahid SA, Taha
FK, Abdelfattah MA (eds) Developments in soil classication, land use planning and policy
implications-innovative thinking of soil inventory for land use planning and management of
land resources. Springer, Dordrecht, pp 147164
KISR (1999) Soil survey for the state of Kuwait volume IV: semi-detailed survey. AACM
International, Adelaide
Kovda VA, Szabolcs I (eds) (1979) Modelling of soil salinization and alkalization: supplementum.
Vol 28 of Agrokemia es Talajtan (Agrochemistry and Soil Science), 207 pp
Mashali AM (1995) Integrated soil management for sustainable use of salt-affected soils and
network activities.Proceedings of the international workshop on integrated soil management
for sustainable use of salt-affected soils. 610 November 1995. Bureau of Soils and Water
Management, Manila, Philippines, pp 5575
Massoud FI (1974) Salinity and alkalinity. In: a world assessment of soil degradation. An interna-
tional program of soil conservation. Report of an expert consultation on soil degradation, FAO,
UNEP, Rome, Italy, pp 1617
Massoud FI (1977) Basic principles for prognosis and monitoring of salinity and sodicity. Pro-
ceedings of the international conference on managing saline waters for irrigation. 1620 Aug
1976, Texas Tech University, Lubbock, Texas, USA, pp 432454
Massoud FI (1981) Salt affected soils at a global scale for control. FAO Land and Water Devel-
opment Division Technical Paper, Rome, Italy, 21pp
Metternicht GI, Zinck JA (2003) Remote sensing of soil salinity: potentials and constraints. Remote
Sens Environ 85(1):120
Oldeman LR, Hakkeling RTA, Sombroek WG (1991) World map of the status of human-induced
soil degradation. An explanatory note. Second revised edition. International Soil Reference and
Information Center (ISRIC), Wageningen, 35 pp
Pazira E (1999) Land reclamation research on soil physico-chemical improvement by salt leaching
in southwest part of Iran. IERI, Karaj
Ponnamperuma FN (1984) Role of cultivar tolerance in increasing rice production on saline-lands.
In: Staple RC, Toenniessen GH (eds) Salinity tolerance in plants: strategies for crop improve-
ment. Wiley, New York, pp 255271
52 2 Soil Salinity: Historical Perspectives and a World Overview of the Problem
Postel S (1989) Water for agriculture: facing the limits. Worldwatch paper 93. Worldwatch
Institute, Washington DC, USA, 54 pp
Qadir M, Quillerou E, Nangia V, Murtaza G, Singh M, Thomas RJ, Drechsel P, Noble AD (2014)
Economics of salt-induced land degradation and restoration. Nat Res Forum 38(4):282295
Shahid SA (2013) Developments in salinity assessment, modeling, mapping, and monitoring from
regional to submicroscopic scales. In: Shahid SA, Abdelfattah MA, Taha FK (eds) Develop-
ments in soil salinity assessment and reclamation innovative thinking and use of marginal soil
and water resources in irrigated agriculture. Springer, Dordrecht\Heidelberg\New York\London,
pp 343
Shahid SA, Omar SAS, Grealish G, King P, El-Gawad MA, Al-Mesabahi K (1998) Salinization as
an early warning of land degradation in Kuwait. Probl Desert Dev 5:812
Shahid SA, Abo-Rezq H, Omar SAS (2002) Mapping soil salinity through a reconnaissance soil
survey of Kuwait and geographic information system. Annual research report, Kuwait Institute
for Scientic Research, Kuwait, KSR 6682, pp 5659
Shahid SA, Abdelfattah MA, Omar SAS, Harahsheh H, Othman Y, Mahmoudi H (2010) Mapping
and monitoring of soil salinization remote sensing, GIS, modeling, electromagnetic induction
and conventional methods case studies. In: Ahmad M, Al-Rawahy SA (eds) Proceedings of
the international conference on soil salinization and groundwater salinization in arid regions, vol
1. Sultan Qaboos University, Muscat, pp 5997
Shahid SA, Abdelfattah MA, Wilson MA, Kelley JA, Chiaretti JV (2014) United Arab Emirates
keys to soil taxonomy. Springer, Dordrecht/Heidelberg/New York/London, 108 pp
Soil Survey Staff (2014) Keys to soil taxonomy 12th ed. US Department of Agriculture, Natural
Resources Conservation Service, US Government Printing Ofce, Washington DC, 360 pp
Szabolcs I (1974) Salt-affected soil in Europe. Martinus Nijhoff, The Hague, 63 pp
Szabolcs I (1989) Salt-affected soils. CRC Press, Boca Raton, 274 pp
Tanji KK (1990) Nature and extent of agricultural salinity. In: Tanji KK (ed) Agricultural salinity
assessment and management. ASCE manuals and reports on engineering practice no 71, ASCE
New York, USA, pp 117
UNEP (1992) Proceedings of the Ad-hoc expert group meeting to discuss global soil database and
appraisals of GLASOD/SOTER, 2428 February 1992, Nairobi, Kenya, 39 pp
Wiley GR (1953) Prehistoric settlement patterns in the Viru Valley, Peru. Smithsonian Institute,
Bureau of American Ethnology, Bulletin 155 Washington DC, USA XXII+454 pp (+60 plates)
The opinions expressed in this chapter are those of the author(s) and do not necessarily reect the
views of the IAEA, its Board of Directors, or the countries they represent.
Open Access This chapter is licensed under the terms of the Creative Commons Attribution 3.0
IGO license (https://creativecommons.org/licenses/by/3.0/igo/), which permits use, sharing, adap-
tation, distribution and reproduction in any medium or format, as long as you give appropriate credit
to the IAEA, provide a link to the Creative Commons license and indicate if changes were made.
The use of the IAEAs name for any purpose other than for attribution, and the use of the IAEAs
logo, shall be subject to a separate written license agreement between the IAEA and the user and is
not authorized as part of this CC-IGO license. Note that the link provided above includes additional
terms and conditions of the license.
The images or other third party material in this chapter are included in the chapters Creative
Commons license, unless indicated otherwise in a credit line to the material. If material is not
included in the chapters Creative Commons license and your intended use is not permitted by
statutory regulation or exceeds the permitted use, you will need to obtain permission directly from
the copyright holder.
IGO
IGO
References 53
... Waterlogging and soil salinization, known as the twin menace of poor drainage conditions, have been aggravated all over the world and have become a national threat to agriculture in many countries ( Figure 2). Globally, it was estimated that more than 800 million hectares of land could be considered salt-affected [18][19][20]. growing season due to mid-summer drainage practices. The aim is to investigate whether or not it is necessary to modify the input module of the DRAINMOD model and include the surface depression capacity as a time-variable value. ...
... Waterlogging and soil salinization, known as the twin menace of poor drainage conditions, have been aggravated all over the world and have become a national threat to agriculture in many countries ( Figure 2). Globally, it was estimated that more than 800 million hectares of land could be considered salt-affected [18][19][20]. The above-mentioned threats of waterlogging and soil salinization highlight the great need for particular practices that help poorly drained lands get rid of their excess water to ensure the desired conditions for crops, soil, and the surrounding environment. ...
Article
Full-text available
Practicing agricultural drainage strategies is necessary to manage excess water in poorly drained irrigated agricultural lands to protect them from induced waterlogging and salinity problems. This paper provides an overview of subsurface drainage strategies and the modeling of their performance using the DRAINMOD model. Given that the DRAINMOD model considers a fixed value of the surface depression capacity (SDC) for the whole simulation period, which does not suit many agricultural practices, the paper then assesses the model’s performance under time-variable SDC. It was revealed that adopting a fixed value of SDC for the whole simulation period in the DRAINMOD model causes it to produce improper predictions of the water balance in farmlands characterized by time-variable SDC. Such a model drawback will also adversely impact its predictions of the nitrogen and phosphorus fate in farmlands, which represent major inputs when managing both the agricultural process and agricultural water quality. Researchers should pay attention when applying the DRAINMOD model to farmlands characterized by time-variable SDC. Moreover, it is recommended that the DRAINMOD input module be improved by considering changes in SDC during the simulation period to ensure better management of the agricultural process and agricultural water.
... Salinity is considered as one of the most serious global problems particularly in the arid and semi-arid regions of the world which affects many metabolic processes of plants and reduces the growth and productivity of many crops [1]. Over 400 million hectares are affected by either salinity or sodicity, which are over 6% of the world land area [2]. ...
... Over 400 million hectares are affected by either salinity or sodicity, which are over 6% of the world land area [2]. Approximately 20% of total cultivated and 33% of irrigated agricultural lands are affected by salinity [1,2]. Salinity causes adverse effects at molecular, biochemical, and physiological levels, negatively affecting crop productivity [3]. ...
Article
Full-text available
Salicylic acid (SA) is one of the strongest candidates to be used as a salinity moderator. A hydroponic experiment was conducted to evaluate the effect of foliar application of SA (0.00, 0.75 and 1.50 mM) on growth, productivity, and some physiological and biochemical parameters of French beans (Phaseolus vulgaris L.) continuously exposed to three NaCl levels (0, 50 and 100 mM). NaCl treatment significantly reduced vegetative growth parameters (between 16–50%), membrane stability (10–15%), relative water content (25–31%), chlorophyll content (21–42%), macro- and micronutrient levels (13–52% and 4–49%, respectively), growth promoters (auxins, gibberellins, and cytokinins; 11–28%), and yield of green pods (22–39%), while the phenolic compounds contents (35–55%), total antioxidant capacity (34–51%), proline (60–100%) and malondialdehyde (18–51%) contents, peroxidase activity (35–41%), Na+ (122–152%) and Cl− (170%) ions and abscisic acid (20–30%) contents were significantly increased compared to the non-salt-stressed controls. Foliar application of SA at 0.75 mM was able to overcome the adverse effects of NaCl stress to variable extent, which allowed for close to 90% of the yield of control plants to be reached. In conclusion, this study demonstrated that foliar spraying of SA helped to reduce the harmful effects of NaCl stress on French bean via regulation of some physiological and biochemical processes. This could be the basis of an effective and low-cost strategy to cope with salt stress.
... Global food production should increase by 50% by 2050 to feed a population that will rise to 10 × 10 9 people [1]. However, soil salinity affects over 109 × 10 6 ha of cropland worldwide, reducing yields in more than 50% of the surface of the most productive agricultural areas-those cultivated under irrigation in arid and semi-arid regions [2][3][4][5][6]. The source of high salt concentration is primarily the presence of salt in irrigation water and the accumulation of Na + and Cl − in soils [2]. ...
... However, soil salinity affects over 109 × 10 6 ha of cropland worldwide, reducing yields in more than 50% of the surface of the most productive agricultural areas-those cultivated under irrigation in arid and semi-arid regions [2][3][4][5][6]. The source of high salt concentration is primarily the presence of salt in irrigation water and the accumulation of Na + and Cl − in soils [2]. ...
Article
Full-text available
Soil salinity is becoming one of the most critical problems for agriculture in the current climate change scenario. Growth parameters, such as plant height, root length and fresh weight, and several biochemical stress markers (chlorophylls, total flavonoids and proline), have been determined in young plants of Solanum melongena, its wild relative Solanum insanum, and their interspecific hybrid, grown in the presence of 200 and 400 mM of NaCl, and in adult plants in the long-term presence of 80 mM of NaCl, in order to assess their responses to salt stress. Cultivated eggplant showed a relatively high salt tolerance, compared to most common crops, primarily based on the control of ion transport and osmolyte biosynthesis. S. insanum exhibited some specific responses, such as the salt-induced increase in leaf K+ contents (653.8 μmol g−1 dry weight) compared to S. melongena (403 μmol g−1 dry weight) at 400 mM of NaCl. Although there were no substantial differences in growth in the presence of salt, biochemical evidence of a better response to salt stress of the wild relative was detected, such as a higher proline content. The hybrid showed higher tolerance than either of the parents with better growth parameters, such as plant height increment (7.3 cm) and fresh weight (240.4% root fresh weight and 113.3% shoot fresh weight) at intermediate levels of salt stress. For most biochemical variables, the hybrid showed an intermediate behaviour between the two parent species, but for proline it was closer to S. insanum (ca. 2200 μmol g−1 dry weight at 200 mM NaCl). These results show the possibility of developing new salt tolerance varieties in eggplant by introducing genes from S. insanum.
... Therefore, adding organic material to these soils not only raises organic levels but also provides available absorbable nutrients to plants (Ameen et al. 2019). Furthermore, almost 35% of the agricultural lands suffer from salinity (Shahid et al. 2018;Molle 2019). Thus, applying KH to sandy soil represents a promising natural resource and a better alternative that could be used effectively to increase organic matter levels and improve soil nutrition status, crop growth, and productivity (Ibrahim and Ali 2018;Saad 2020). ...
Article
Full-text available
Previous studies have demonstrated the impact of potassium humate (KH) and chitosan (CH) on ameliorating drought effects, but their combined applications in promoting these benefits are still unfound. Therefore, the current study aims to evaluate the efficacy of KH and CH on corn growth, yield, nutrient contents, and water productivity under full and limited irrigation conditions. Under the drip irrigation system, a split-plot experiment was performed with three replications in the second week of February in the seasons of 2021 and 2022. The main plot was equipped with a valve and a flow emitter to control the amount of the targeted irrigation levels (full irrigation and limited irrigation from the development stage onwards), as well as four foliar applications in the subplot (0, CH 500 mg l−1, KH 3000 mg l−1, and CH 500 mg l−1 + KH 3000 mg l−1). It was found that separate foliar applications of KH or combined foliar applications of KH + CH had a significant impact on the most examined traits. However, compared to the control, adopting limited irrigation and applying combined applications thereof have significantly increased iron, zinc, manganese, oil, protein, yield, and water productivity. In addition, this combination decreased proline, and the maximum reduction was observed for the combined application with adopting full irrigation. In arid regions, the researcher recommends treating stressed plants with combined foliar applications of KH + CH, which could help plants overcome the negative effects of drought and attain the highest yield and water productivity.
... The relationship between human civilizations and salinity has existed for thousands of years. The total area of saline and sodium lands is likely to be approximately 10% of arable land worldwide [1]. Many of the factors that lead to soil salinization are being exacerbated by climate change and it will get worse and worse over the next few years based on the indicators that the scientific world takes into consideration. ...
Article
Full-text available
The Mediterranean basin is rich in wild edible species which have been used for food and medicinal purposes by humans throughout the centuries. Many of these species can be found near coastal areas and usually grow under saline conditions, while others can adapt in various harsh conditions including high salinity. Many of these species have a long history of gathering from the wild as a source of food. The aim of this contribution is an overview on the most important halophyte species (Salicornia sp. pl., Arthrocaulon macrostachyum (Moric.) Piirainen & G. Kadereit, Soda inermis Fourr., Cakile maritima Scop., Crithmum maritimum L., Reichardia picroides (L.) Roth., Silene vulgaris (Moench) Garcke subsp. tenoreana (Colla) Soldano & F. Conti, Allium commutatum Guss., Beta vulgaris L. subsp. maritima (L.) Arcang., Capparis spinosa L.) that traditionally have been gathered by rural communities in southern Italy, with special interest on their ecology and distribution, traditional uses, medicinal properties, marketing and early attempts of cultivation. It is worth noting that these species have an attractive new cash crop for marsh marginal lands.
... Climate change is also triggering more soils to become saline through increased evaporation of irrigation water associated with water shortages and increased soil temperatures [1,2]. Globally, an area of 9.54 × 10 8 has been declared as salt affected [3]. Of the area of land that is fit for arable production, 10% has deteriorated due to salinity or sodicity. ...
Article
Full-text available
Salt-affected soil reclamation provides opportunities for crop production and carbon se-questration. In arid regions such as Pakistan, limited studies have been reported involving soil reclamation and crop production under wheat-maize rotation, but no study has reported predictions on long-term carbon sequestration in reclaimed soils for the treatments used in this study. Thus, a field-scale fallow period and crop production experiment was conducted for wheat-maize rotation on salt-affected soils in Pakistan for 3 years to check the effectiveness of organic amendments for reclamation of the salt-affected soils, carbon sequestration and food grain production. Treatments used were the control (with no additional amendments to reduce salinity), gypsum alone and gyp-sum in combination with different organic amendments (poultry manure, green manure, and farmyard manure). The treatment with gypsum in combination with farmyard manure was most effective at increasing soil carbon (+169% over the three-year period of the trial). The maximum wheat yield was also recorded in year 3 with gypsum in combination with farmyard manure (51%), while the effect of green manure combined with gypsum also showed a significant increase in maize yield in year 3 (49%). Long-term simulations suggested that the treatments would all have a significant impact on carbon sequestration, with soil C increasing at a steady rate from 0.53% in the control to 0.86% with gypsum alone, 1.25% with added poultry manure, 1.69% with green manure and 2.29% with farmyard manure. It is concluded that food crops can be produced from freshly reclaimed salt-affected soils, and this can have added long-term benefits of carbon sequestration and climate change mitigation.
... This will require more farmland to meet the increasing food demand, but environmental factors including rising temperatures, erratic rainfall patterns, drought and soil salinity already limit land suitable for agricultural production [4]. Soil salinization is a major contributor to the degradation of agricultural land and reductions in crop productivity, with salinity affecting over 800 million hectares of land or 6% of the total worldwide land area [5]. Crop growth is impeded by salinity due to the toxicity of certain ions, nutrient imbalances, and osmotic stress [6], and low levels of organic matter in the soil, all of which can amplify the unfavourable effects of salinization [7,8]. ...
Article
Full-text available
Soil salinity is one of the major abiotic constraints in agricultural ecosystems worldwide. High salinity levels have negative impacts on plant growth and yield, and affect soil physicochemical properties. Salinity also has adverse effects on the distribution and abundance of soil microorganisms. Salinity problems have previously been addressed in research, but most approaches, such as breeding for salt tolerant varieties and soil amelioration, are expensive and require years of efforts. Halotolerant plant growth-promoting rhizobacteria (HT-PGPR) secrete secondary metabolites, including osmoprotectants, exopolysaccharides, and volatile organic compounds. The importance of these compounds in promoting plant growth and reducing adverse effects under salinity stress has now been widely recognised. HT-PGPR are emerging as effective biological strategies for mitigating the harmful effects of high salinity; improving plant growth, development, and yield; and remediating degraded saline soils. This review describes the beneficial effects and growth-promoting mechanisms of various HT-PGPR, which are carried out by maintaining ion homeostasis, increasing nutrient availability, and the producing secondary metabolites, osmoprotectants, growth hormones, and volatile organic compounds. Exploring suitable HT-PGPR and applications in agriculture production systems can play a crucial role in reducing the adverse impacts of salinity stress and sustainable crop productivity.
... "Soil salinity is the 2 nd most importantfeaturethat causesearth degradation after soil erosion, leads to decline in agricultural economic outputs for 10,000 years" [14]. Poor salinity management can because soil solicits of farming soils, wheresodium in cationic form binds to anionic natured clay, leads to clay swelling and dispersal, consequentlydeclining the crop productivity. ...
Article
Wheat constitutes a central position for ensuring food and nutritional security; however, rapidly rising soil and water salinity pose a serious threat to its production globally. Salinity stress is a universal dilemma that is happening due to climate change. It affects hectares of arable land. Main focus regarding improving salinity tolerance in plants has been given to Na+ exclusion/ Na+ compartmentalization and enhanced ROS system. Besides this, ameliorative activity of phytohormones, nutrients, amino acids and organic osmolytes has also been widely studied. Exploring traits in wild genotype aids search for better solutions. Based upon phenotype screening, novel genes involving salinity tolerance will be easily identified. Moreover, selected mutants can be used to validate the functions of salt genes. Wheat plants utilize a range of physiological biochemical and molecular mechanisms to adapt under salinity stress at the cell, tissue as well as whole plant levels to optimize the growth, and yield by off-setting the adverse effects of saline environment. Recently, various adaptation and management strategies have been developed to reduce the deleterious effects of salinity stress to maximize the production and nutritional quality of wheat. Thereby, this review highlights effects of salt tolerance, physiological mechanisms behind salt tolerance and transgenic wheat that are potential indicators of salinity stress tolerance.
Article
Full-text available
Abiotic stresses adversely affect rice yield and productivity, especially under the changing climatic scenario. Exposure to multiple abiotic stresses acting together aggravates these effects. The projected increase in global temperatures, rainfall variability, and salinity will increase the frequency and intensity of multiple abiotic stresses. These abiotic stresses affect paddy physiology and deteriorate grain quality, especially milling quality and cooking characteristics. Understanding the molecular and physiological mechanisms behind grain quality reduction under multiple abiotic stresses is needed to breed cultivars that can tolerate multiple abiotic stresses. This review summarizes the combined effect of various stresses on rice physiology, focusing on grain quality parameters and yield traits, and discusses strategies for improving grain quality parameters using high-throughput phenotyping with omics approaches.
Article
Full-text available
Food security concerns and the scarcity of new productive land have put productivity enhancement of degraded lands back on the political agenda. In such a context, salt-affected lands are a valuable resource that cannot be neglected nor easily abandoned even with their lower crop yields, especially in areas where significant investments have already been made in irrigation and drainage infrastructure. A review of previous studies shows a very limited number of highly variable estimates of the costs of salt-induced land degradation combined with methodological and contextual differences. Simple extrapolation suggests that the global annual cost of salt-induced land degradation in irrigated areas could be US$ 27.3 billion because of lost crop production. We present selected case studies that highlight the potential for economic and environmental benefits of taking action to remediate salt-affected lands. The findings indicate that it can be cost-effective to invest in sustainable land management in countries confronting salt-induced land degradation. Such investments in effective remediation of salt-affected lands should form part of a broader strategy for food security and be defined in national action plans. This broader strategy is required to ensure the identification and effective removal of barriers to the adoption of sustainable land management, such as perverse subsidies. Whereas reversing salt-induced land degradation would require several years, interim salinity management strategies could provide a pathway for effective remediation and further showcase the importance of reversing land degradation and the rewards of investing in sustainable land management.
Data
Full-text available
Middle East region can be divided into two simple zones, the northern mountain belt, comprising the states of Turkey, Iran and northern part of Iraq. The second zone formed by plains and dissected plateaus. Middle East region is a region with the highest rate of population growth in the world, from 102 millions on 1960 to 318 millions on 2000, with annual growth about 3%. It is facing environmental problems of land degradation and desertification. Whereas the most of Arabian Peninsula is free of perennial vegetation. For most areas shifting sand dunes are incapable of sustaining plants life. Most of marginal lands in Middle East are permanent pastures of 1.35 millions sq. km, and 85% of them are considered in danger to desertification. These marginal lands are subject to human activities and susceptible to inappropriate land use practices, such as overgrazing, fuel cutting and inadequate cultivation. The study concerned with the utilization of Remote Sensing and Geographic Information System (GIS) techniques to perform land cover assessment and mapping, to understand land degradation and desertification processes, to integrate and manipulate many factors and layers with different forms and to design new methodologies to improve effects of future actions. The study is divided into three major topics: Land cover assessment and mapping, construction of a geographic information system (GIS) contained the available data with concern on environment and land degradation features and the third subject is desertification assessment and mapping. The land cover assessment and mapping is based mainly upon satellite images, particularly NOAA AVHRR 1-km resolution images. Tree structure method was applied and four levels of classification were performed to get a final result of land cover. Thirteen classes could be recognized. 60% of study area belongs to deserted land cover types and 33% are of vegetation cover types and 7% are internal water bodies, sabkhats and sand on the beaches. The accuracy result shows that 82% of classification errors are avoided, which is cons idered to be good enough. Environmental GIS database were created from different source of information. Data gathered are of two types: spatial data such as satellite images, topographic maps, soil maps, and land cover maps. The second type of data used in this study is tabular data, examples are census records, economic data and hydrographic data. More than 75 layers were collected, many tabular data were converted into layers, and this procedure facilitated the manipulation of data. Desertification Mapping Units (DMU) layer was created by the integration of land cover layer, soil units map, and national boundaries of countries located in the study area. The DMUs allowed us to analyze and assess the different types of land degradation. Through this layer we could put equations about desertification and others environmental features, and then find the answers in form of maps, tables or charts. An Integrated Approach is of utmost important for desertification study, which reflect the complexity of desertification process. So the desertification assessment in this study is the outcome of a combination of social factors, economic factors, climatic factors and physical factors. This method allowed taking in consideration all possible and available variables of desertification processes. We note that the application of such approach requires the use of geographic information system (GIS). Finally the statistic results of this study show the gravity of desertification problems in all levels. It is supposed that all the area is subject to desertification, mainly by vegetation degradation process, where 40% of study area is severely and very severely affected by vegetation degradation, followed by wind erosion process (27% severe and very severe wind erosion). So we conclude that 6% of land area in Middle East is slightly desertified, 21% is moderately desertified, 31% is severely desertified and 11% is very severely desertified. Without doubt these results show the gravity of desertification problem in the study area.
Article
Examines the need for irrigation, indigenous irrigation, irrigation water supply, application of irrigation water and environmental aspects of arid land irrigation. The paper presents brief outlines of the Bakolori, Kano River, and S Chad irrigation projects (Nigeria) and a more detailed case study of the Bura Irrigation Project (Kenya). -C.J.Barrow
Article
Irrigated agriculture has faced the challenge of sustaining its productivity for centuries. Because of natural hydrological and geochemical factors, as well as irrigation-induced activities, soil and water salinity and associated drainage problems continue to plague agriculture. The problems have extended far beyond the farmlands, where saline soils and waters impair crop production. Practices based on the presumption that saline drainage waters will somehow, somewhere, be discharged are now being challenged. New and extended regulations on the discharge of nonpoint source pollutants in agricultural drainage waters are expected in the United States. This chapter presents an overview of the nature of salinity in soils and waters, its extent from global to regional scales, the reactivity of salts and salt flows, and the concerns of agriculture and other sectors of society.
Article
Progressive changes in soil salinity and sedimentation contributed to the breakup of past civilizations.