80
WALLACE H. FULLER
are not available. The few broad reconnaissance-type maps give sketch
information. As pointed out by Dregne (1967) the most detailed information about the soils is contained in the UNESCO "Arid Zone Research
Series" (Pichi-Sermolli, 1955).
The Somali-Chalbi Desert soils, morphologically, are undeveloped. Some
fine-textured, reddish-clay soils occur in plains of the Kenya-Somalia border region as well as in the upland associated with the Buiba and Scebeli
Rivers.
Salt-affected soils occupy large areas of coarse and medium soils of
French Somaliland as lime and gypsum accumulations. The coastal plains
are well known for their saline characteristics. The Danakil pan is high
in salts. Irrigation of certain soils has led to a salinization because of poor
drainage conditions.
Stony and rock detritus are found in all parts of the Somali-Chalbi
Desert but are concentrated most in French Somaliland. Sand dunes are
confined mostly to the coastal plains. Soils formed on these materials are
skeletal and poorly developed. The vegetation resembles that of the Sahara
under comparable climatic conditions.
D. ARABIAN
Soils information on the area delineated as the Arabian Desert is extremely limited. Israel provides the best source material. Scant information
is available on Iraq, Iran, and Saudi Arabian deserts (Dregne, 1967).
The broad expanse of Saudi Arabia of thin sandy soils and sand dunes
and stony surfaces is better known for oil than agriculture. Irrigation quality water is lacking in most of Saudi Arabia, Kuwait, and Israel. The soils
are in a very primitive state of development under the influence of prevailing arid conditions and scarcity or absence of natural vegetation. Outcroppings of partially weathered parent material, not yet soil, frequent this
region (Abu Fakhr, 1961). Salt flats, "gatch pan" (lime-silica-sand
indurated layers) and deep layers of gypsum and lime are common. Almost
all plant vegetation is excluded although a native salt-tolerant plant,
Zygophyllum coccinium, may grow in these extreme arid areas. Acacia
trees have been planted on the irrigated periphery of the Saudi Arabian
Desert but even these often die as a result of salt accumulation on top
of "gatch." A typical profile described by Abu Fakhr (1961) in Kuwait
is 0-5 cm of white sand over 5-30 cm of fine calcareous sand with some
silt and clay, friable sand continues to the gatch hardpan at about 120-150
cm. Gatch pan is almost impervious to water and perches irrigation water
sufficiently to cause upward movement of salts.
In the northern part, broad plains and tablelands and stony soil surfaces
WALLACE H. FULLER
are not available. The few broad reconnaissance-type maps give sketch
information. As pointed out by Dregne (1967) the most detailed information about the soils is contained in the UNESCO "Arid Zone Research
Series" (Pichi-Sermolli, 1955).
The Somali-Chalbi Desert soils, morphologically, are undeveloped. Some
fine-textured, reddish-clay soils occur in plains of the Kenya-Somalia border region as well as in the upland associated with the Buiba and Scebeli
Rivers.
Salt-affected soils occupy large areas of coarse and medium soils of
French Somaliland as lime and gypsum accumulations. The coastal plains
are well known for their saline characteristics. The Danakil pan is high
in salts. Irrigation of certain soils has led to a salinization because of poor
drainage conditions.
Stony and rock detritus are found in all parts of the Somali-Chalbi
Desert but are concentrated most in French Somaliland. Sand dunes are
confined mostly to the coastal plains. Soils formed on these materials are
skeletal and poorly developed. The vegetation resembles that of the Sahara
under comparable climatic conditions.
D. ARABIAN
Soils information on the area delineated as the Arabian Desert is extremely limited. Israel provides the best source material. Scant information
is available on Iraq, Iran, and Saudi Arabian deserts (Dregne, 1967).
The broad expanse of Saudi Arabia of thin sandy soils and sand dunes
and stony surfaces is better known for oil than agriculture. Irrigation quality water is lacking in most of Saudi Arabia, Kuwait, and Israel. The soils
are in a very primitive state of development under the influence of prevailing arid conditions and scarcity or absence of natural vegetation. Outcroppings of partially weathered parent material, not yet soil, frequent this
region (Abu Fakhr, 1961). Salt flats, "gatch pan" (lime-silica-sand
indurated layers) and deep layers of gypsum and lime are common. Almost
all plant vegetation is excluded although a native salt-tolerant plant,
Zygophyllum coccinium, may grow in these extreme arid areas. Acacia
trees have been planted on the irrigated periphery of the Saudi Arabian
Desert but even these often die as a result of salt accumulation on top
of "gatch." A typical profile described by Abu Fakhr (1961) in Kuwait
is 0-5 cm of white sand over 5-30 cm of fine calcareous sand with some
silt and clay, friable sand continues to the gatch hardpan at about 120-150
cm. Gatch pan is almost impervious to water and perches irrigation water
sufficiently to cause upward movement of salts.
In the northern part, broad plains and tablelands and stony soil surfaces