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Sudan
Soils
The country's soils can be divided geographically into three
categories. These are the sandy soils of the northern and west
central areas, the clay soils of the central region, and the laterite
soils of the south. Less extensive and widely separated, but of
major economic importance, is a fourth group consisting of alluvial
soils found along the lower reaches of the White Nile and Blue
Nile rivers, along the main Nile to Lake Nubia, in the delta of
the Qash River in the Kassala area, and in the Baraka Delta in
the area of Tawkar near the Red Sea in Ash Sharqi State.
Agriculturally, the most important soils are the clays in central
Sudan that extend from west of Kassala through Al Awsat and southern
Kurdufan. Known as cracking soils because of the practice of allowing
them to dry out and crack during the dry months to restore their
permeability, they are used in the areas of Al Jazirah and Khashm
al Qirbah for irrigated cultivation. East of the Blue Nile, large
areas are used for mechanized rainfed crops. West of the White
Nile, these soils are used by traditional cultivators to grow
sorghum, sesame, peanuts, and (in the area around the Nuba Mountains)
cotton. The southern part of the clay soil zone lies in the broad
floodplain of the upper reaches of the White Nile and its tributaries,
covering most of Aali an Nil and upper Bahr al Ghazal states.
Subject to heavy rainfall during the rainy season, the floodplain
proper is inundated for four to six months--a large swampy area,
As Sudd, is permanently flooded--and adjacent areas are flooded
for one or two months. In general this area is poorly suited to
crop production, but the grasses it supports during dry periods
are used for grazing.
The sandy soils in the semiarid areas south of the desert in
northern Kurdufan and northern Darfur states support vegetation
used for grazing. In the southern part of these states and the
western part of southern Darfur are the so-called qoz
sands. Livestock raising is this area's major activity, but a
significant amount of crop cultivation, mainly of millet, also
occurs. Peanuts and sesame are grown as cash crops. The qoz
sands are the principal area from which gum arabic is obtained
through tapping of Acacia senegal (known locally as hashab).
This tree grows readily in the region, and cultivators occasionally
plant hashab trees when land is returned to fallow.
The laterite soils of the south cover most of western Al Istiwai
and Bahr al Ghazal states. They underlie the extensive moist woodlands
found in these provinces. Crop production is scattered, and the
soils, where cultivated, lose fertility relatively quickly; even
the richer soils are usually returned to bush fallow within five
years.
Data as of June 1991
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