Geoscience Reference
In-Depth Information
Africa
The huge continent of Africa cannot be subsumed into one story. Its soils are varied
and their distribution very patchy, depending on slope, bedrock, and rainfall. Two
case studies aim at showing the diversity. Places as different as the Nile valley and
the Kalahari desert, to name but two of the iconic landscapes of the continent, do
exhibit very different histories with regard to their soils. Kate Showers has pointed
out how greatly the perception of African soils has been shaped and in
uenced by
colonial, European, mindsets and expectations. Many African regions offer no
historical sources pre-dating colonial impacts; this scarcity of evidence and lack of
research makes it dif
cult to compare African agricultural societies with those of
other continents. We have to rely on ethnopedology for case studies except for the
Nile valley.
47
Deirdre Birmingham has done ethnological research to investigate the soil
knowledge of the B
people, who
live in the equatorial forest zone, distinguished from 10 to 12 mutually exclusive
soil types, on the basis of gravel, texture, and color. The B
é
t
é
and Senufro peoples in Cote d
'
Ivoire. The B
é
t
é
é
t
é
used their senses
—
touch, sight, smell, and even hearing (for testing soil grittiness)
to determine soil
properties. While the determining characteristic was absolute, other properties
varied. The range for nondetermining properties, such as that of colors, was often
described. Although names for the same soil may vary due to dialectical differences
among villages, descriptions of each soil type were essentially the same. Animals,
earthworms, and termites that carry soils to the surface help the B
—
identify soil
types, particularly subsoils. The Senufo, living in the guinea-savanna zone, used an
entirely different system. Land types include land that
é
t
é
oods annually (fa
a or
'
fadoulgou), land that does not
gay), and land that
is barren and rocky (yandalga). Each valley bottom may carry its own name,
sometimes given as the soil or land type. While the Senufo know that gravelly soils
are found on the crests and upper slopes, with softer soils on the midslopes to valley
bottoms, they do not classify soils. They know, however, variations in their plots
and prefer certain soil qualities. The features they use to distinguish among soils
(gravel content, texture, and color) in
ood annually (shopegay or sho
uence the soil properties of importance to
them: these are primarily the rates of water in
ltration and retention, and soil
workability. The main difference to the B
system is the integration of the dis-
tinction between soil types into those of land: Each place is characterized by a
speci
é
t
é
c set of qualities, and soil is not analytically taken apart from these.
48
Systems of soil description and sensually aided determination of soil qualities
are widespread among agricultural people. As the two African examples show, the
systems can differ markedly, but all agricultural peoples do possess traditional
ecological soil knowledge acquired through experience and transmitted orally as
part of their life-world knowledge. Oral traditions are often broken due to people
47
Cooper (
1977
).
48
Birmingham (
2003
).
