M. DESERT SOILS
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are found (regs, hamadas) even to the extent, in many places of having
stony pavement characteristics. Calcium and gypsum layers accumulate in
these soils.
The medium- to fine-textured soils follow the Tigris, Euphrates, and
Jordan rivers. These old flood plain areas are used extensively for
irrigated agriculture (Ravikovitch, 1960). Solonchak, Solonetz, and solodized-Solonetz are found in the alluvial irrigated plains of the Mesopotamian and other irrigated areas as well as depressions such as near
the Dead Sea.
In the Central Negev of Israel the distribution of soils is said to be ( 1 )
rocky slopes 42% of the area; (2) dunes and plains, 2 2 % ; (3) loessial
plains, 12%; (4) sandy plains, 10%; (5) gravelly (hamadas) plains, 8%;
wadis, about 6%, etc. (Seligman et al., 1961).
On the less arid plains and plateau margins of the desert where rainfall
ranges from 25 to 30 cm, Sierozem and isohumic brown soils have developed on loess and sand.
The Southern Arabian Desert is very similar to the Sahara. Most of
the Arabian Peninsula is extremely arid, and soils develop poorly if at all.
The same type of vegetation as found in the Sahara extends across Central Asia and into India (McGinnies, 1967). Almost no true succulents
occur. Perennials include halophytes. Ephemerals follow rains. The
Anabasis articulata/Rétama raetam plant communities dominate the sandy
plains of Negrev. In lower Jordan Anabasis articulata/Zilla spinosa communities are common. The most common plants in Palestine are Pistacia
atlantica t Zizyphus lotus, Rétama raetam var. raetam, Phlomis brachyodon, Rhus tripartita, Artemisia herba-alba, Noaea mucronata, Anabasis
haussknechtii, Haloxylon articulatum, and Achillea santolina.
E. IRANIAN
The Iranian Deserts are defined to include the arid areas of Iran,
Afghanistan, and Pakistan which encompass (a) the Dasht-e-Kavir in the
northwest, (b) Kavir-i-Namak in the north, (c) the Dasht-e-Lut in the
southwest, (d) the Dasht-i-Naomid in the east, and (e) the Dasht-i-Margo
in the southeast.
The Dasht-e-Kavir is known most widely for its extensive salt-crusted
soils of solonchaks or halomorphics. Gypsum beds and saline marls underlie these soils. Salty soils also occur along the Persian Gulf, the Gulf of
Oman, and the Arabian Sea.
Coarse-textured soils predominate in the Iranian Deserts. Fans of alluvial soils on upper slopes next to mountains and hills are coarse textured
as are the Gray Desert soils lower down slope. Most are limy (Dewan and
81
are found (regs, hamadas) even to the extent, in many places of having
stony pavement characteristics. Calcium and gypsum layers accumulate in
these soils.
The medium- to fine-textured soils follow the Tigris, Euphrates, and
Jordan rivers. These old flood plain areas are used extensively for
irrigated agriculture (Ravikovitch, 1960). Solonchak, Solonetz, and solodized-Solonetz are found in the alluvial irrigated plains of the Mesopotamian and other irrigated areas as well as depressions such as near
the Dead Sea.
In the Central Negev of Israel the distribution of soils is said to be ( 1 )
rocky slopes 42% of the area; (2) dunes and plains, 2 2 % ; (3) loessial
plains, 12%; (4) sandy plains, 10%; (5) gravelly (hamadas) plains, 8%;
wadis, about 6%, etc. (Seligman et al., 1961).
On the less arid plains and plateau margins of the desert where rainfall
ranges from 25 to 30 cm, Sierozem and isohumic brown soils have developed on loess and sand.
The Southern Arabian Desert is very similar to the Sahara. Most of
the Arabian Peninsula is extremely arid, and soils develop poorly if at all.
The same type of vegetation as found in the Sahara extends across Central Asia and into India (McGinnies, 1967). Almost no true succulents
occur. Perennials include halophytes. Ephemerals follow rains. The
Anabasis articulata/Rétama raetam plant communities dominate the sandy
plains of Negrev. In lower Jordan Anabasis articulata/Zilla spinosa communities are common. The most common plants in Palestine are Pistacia
atlantica t Zizyphus lotus, Rétama raetam var. raetam, Phlomis brachyodon, Rhus tripartita, Artemisia herba-alba, Noaea mucronata, Anabasis
haussknechtii, Haloxylon articulatum, and Achillea santolina.
E. IRANIAN
The Iranian Deserts are defined to include the arid areas of Iran,
Afghanistan, and Pakistan which encompass (a) the Dasht-e-Kavir in the
northwest, (b) Kavir-i-Namak in the north, (c) the Dasht-e-Lut in the
southwest, (d) the Dasht-i-Naomid in the east, and (e) the Dasht-i-Margo
in the southeast.
The Dasht-e-Kavir is known most widely for its extensive salt-crusted
soils of solonchaks or halomorphics. Gypsum beds and saline marls underlie these soils. Salty soils also occur along the Persian Gulf, the Gulf of
Oman, and the Arabian Sea.
Coarse-textured soils predominate in the Iranian Deserts. Fans of alluvial soils on upper slopes next to mountains and hills are coarse textured
as are the Gray Desert soils lower down slope. Most are limy (Dewan and