The Sudan Handbook

48 the sudan handbook

between these flexible strategies of land use and the new demands of

administrative boundaries, individual ownership and entrepreneurial

investment.

Roughly speaking, in Sudan, the further south, the more rain there

is. This rule is not invariable. Where there is high ground there is more

rain, around Jebel Marra in Darfur or in the Nuba hills, for example;

and the extreme south-eastern corner of Sudan is relatively arid. But in

general, the overall amount of rainfall and the extent to which it is spread

through the year both increase towards the south. The area of the three

old southern provinces – Upper Nile, Bahr al-Ghazal and Equatoria – is

generally much greener than the north. The wettest part of Sudan lies

on its borders with the Democratic Republic of Congo and the Central

African Republic. Everywhere, the rain is seasonal, and there are some

months which are likely to see more rain than others – even in the south-

west, where it may rain in any month, there is a pronounced seasonality

to the rain. This is the product of the inter-tropical convergence zone,

the shifting meeting place of high-altitude air streams.

There are also significant differences of soil type, which combine with

the pattern of rainfall to produce varying kinds of vegetation. From north

to south, roughly speaking, the soil changes from sandy to clayish to the

hard red, lateritic soils known as ironstone. In the south, the distinction

between the ironstone plateau of the south-west and the flood-prone,

clayish black cotton soils which lie east and north of them is striking,

affecting vegetation and the possibilities of movement. The black cotton

swells and grows sticky in the rain; it shrinks and cracks as it dries. The

clay plains at the heart of the south are largely grassland. Here travel is

very difficult when the rains are heavy. The ironstone plateau is more

wooded and movement is easier.

Landscape and Technology

Over the last hundred years in most parts of Sudan, human interven-

tion has reshaped the landscape and the possibilities of movement and

The Sudan Handbook, edited by John Ryle, Justin Willis, Suliman Baldo and Jok Madut Jok. © 2011 Rift Valley Institute and contributors communication.^ Railways^ and^ telegraph^ lines^ were^ the^ first^ innovations;^

(www.riftvalley.net).