Agricultural systems in Africa 1500-1800: the role of the
environment
Bricolage and notes towards a paper Sept 23rd 2014
Mats Widgren, Department of Human Geography, Stockholm University
‘Geographical’ factors and environmental determinism
Geographers (especially human geographers) do not usually recognize themselves
when ’geographical’ factors are analysed by economists and economic historians. There are
two reasons for this. First ,the usage of geography as short for naturally given environmental
factors that may influence economic outcome does definitely not resonate with the
understanding of what geography is, regardless if we talk about geography as the lay of the
land, of the varying conditions of the surface of the earth or about the geography as an
academic discipline. In both cases goes without saying that e.g. economic and cultural
conditions are part of geography. The global distribution of GDP in different nations is in that
sense a geographical factor and you cannot explain geography by geography. The fact that
this has to be said as a preamble to a discussion between geographers and economists about
the role of the environment probably to large degree reflects the marginality of academic
geographers in the debate on how the world came to be, or why nations fail.
The second reason why geographers do not feel at home in this debate is the summarily and
often ignorant way that environmental (’geographical’) factors are treated and operationalised
in the economic literature. Many authors assume that latitude in itself is a geographical factor,
while it can only be seen as very rough proxy for temperature, rainfall and hence climate.
Moreover Gallup and Sachs results on the tropics being less productive is often taken for
granted, while what they did show was that that the tropical or equatorial climatic zone was in
fact more productive, but that the geographical tropics also included arid lands, which
contributed to the reduction of the productivity of the intertropical zone (Gallup and Sachs
2000).
Moreover each author that claims to have investigated ’geographical’ factors, focus on
different aspects and on different time perspectives. Some seeks to understand environmental
constraints from an assumed time-less perspective where the productivity of 20th century
agriculture is taken as proxy what was possible in the past (Gallup & Sachs 2000), while other
authors take a long-term perspective and looks at very early biogeographical distributions as
determining present economic outcome (Hibbs & Olsson 2004).
Environmental determinism - an old debate
For geographers it also seems as if some of the economists working with ‘geographical’
factors as causative for economic development are totally ignorant on the long discussion on
environmental determinism, a debate that has been carried out in in geography and
anthropology almost for the most part of the 20th century. After these debates most
geographers are strongly opposed to anything that have a slight smell of environmental
determinism and we are sometimes misunderstood by other scholars, who think that we
oppose that physical factors, climate, soils have an profound influence on the type of
agriculture has been that is developed in a specific environment. That is not the point.
However, what the historical geography of agriculture tells us is that the major regional types
of agriculture of the world cannot be explained on the basis of the environment alone. Areas
with similar environments exhibit types of agriculture that were very different. Geographers
have been aware of the since long (some examples: Whittlesey 1936, 209, Morgan 1988, 69).
Ideas based on environmental determinism have, however continued to thrive in many other
disciplines, not only in economics. It is for example evident that the idea of Oriental
despotism as well as the notion of the Asian mode of production was to large degree based on
a misunderstanding of Marx and Engels of the determining factor that arid Asian
environments supposedly had on modes of production (Blaut 1993, 82-4).
The American anthropologist Betty Meggers in 1954, on the basis of her experience of
archaeological work in South America formulated what she called the law of environmental
limitation on culture. She argued
Differences in soil fertility, climate and other elements determine the productivity of
agriculture, which, in turn, regulates population size and concentration and through this
influences the sociopolitical and even the technological development of culture. (Meggers
1954, 802)
and formulated her law as
the level to which a culture can develop is dependent on the agricultural potential of the
environment it occupies (Meggers 1954, 815).
Her argument was to a large extent based on the contemporary knowledge of archaeology in
the South American rainforest in the Amazon, which she claimed could only support hunting
and gathering or slash-and-burn agriculture. But very early her arguments was criticised on
theoretical grounds by Hirschberg and Hirschberg who reformulated the law into
The level to which a culture develops is dependent on the amount of food the people
know how to raise (Hirschberg & Hirschberg 1957,891)
However, the position that Meggers took on the agricultural potential of the Amazon
rainforest became for a relatively long period part of a general assumption of what kind of
prehistory one would expect there. Towards the end of the last millennium archaeological
research came to reverse that story fundamentally. Complex societies based on dense
settlements and advanced agriculture from pre-Columbian times were discovered and this
completely overthrew Meggers ideas about the “the level to which a culture can develop” in a
tropical rainforest environment (Heckenberger et al. 2003). It has also been shown that the
type of agriculture that formed the basis for these settlement were to a large based on
permanent agriculture rather than on the type of agriculture known from later times in the area
– slash-and-burn. The permanent agriculture was based on a form of soil improvement which
until these archaeological discoveries had not been known. Woody vegetation was charred
and the charcoal incorporated in the soil and formed the basis of what is now known as a new
type of anthropogenic soil – Amazonian Dark Earths (Glaser and Woods 2004). The
discovery that the Amazonia rainforest was not virgin has also raised the issue of a new
research agenda on the cultural history of other rain-forest areas in the world (Willis et. al
2004).
The interpretative mistake that Meggers did was to assume that the type of agriculture that
was practiced in the area in later times, was also a good indication of what type of agriculture
that was possible given the environmental conditions. This led her to conclude that similar
adaptations might have existed in the past.
Recent findings from the central African rain-forests illustrates a similar case, where
assumptions of what was possible in the past were erroneously based on recent agriculture. In
the central African rain forest bananas and tubers play a central for agriculture and it has been
assumed that the beginning of agriculture in this area must have been based on a similar
repertoire of crops. It must however be noted that many of the crops that at present (and in the
recent history) are important in the area and form the basis of the forest vegeculture systems
were of American origin. Based on archaeobotanical evidence Kahlheber and co-authors
show that pearl millet and Bambara groundnuts were cultivated in the rainforests of southern
Cameroon in the period 400 B.C.E. to 400 C.E. These crops have conventionally been seen as
a part of savannah type of agriculture, with its basis much further north. The environment of
the African rain forest is generally considered to be too wet for these crops (Kahlheber et al.
2013). The new finds thus suggest that the more recent forest vegeculture systems should be
considered as a secondary phase of agricultural development in the area, and not the earliest
and only possible adaptation to that environment (Fuller et. al 2013, 22).
The anthropocene – a world of domesticated landscapes
Another factor to take into consideration when role of natural factors for the human
development is discussed is the new understanding of the antiquity of humans role in
changing their environments. While geologists seem to be on their way to accept a definition
of the anthropocene as beginning as late as in the 20th century there is at the same time more
and more evidence to show that humans fundamentally reshaped the global environment in a
much longer time scale. It therefore becomes more and more difficult to define which factors
in the environment that are natural and which are anthropogenic.
Ellis & Rammankutty (2008) argue against the established view of the environments of the
world as consisting of a series of naturally and climatically determined biomes and instead
launch the concept of anthropogenic biomes. They argue that “human-dominated ecosystems
now cover more of the Earth’s land surface than do “wild” ecosystems”. According to them
only 22 percent of land consist of ‘wild’ nature. Moreover this wild nature contributes to only
11 percent of terrestrial net primary production. The conclusion is that “nature” is now
embedded within human systems. It is no longer possible to conserve nature by avoiding
human interactions. The authors accompany their argument with an interesting map based on
a categorisation of areas of the world into different types of anthromes or human biomes.
More and more evidence is now gathered that shows such anthromes go back at least to the
Neolithic revolution. In a recent summary by Jonathan Foley and co-authors the term paleaeo
anthropocene is suggested for the period from the early hominids to industrial revolution.
Anthropogenic biomes have gradually come to dominate the world at least from the neoltihic
revolution. The term domesticated landscapes has also been used to describe this situation.
While climate and landforms are comparatively stable variables of at least the last 2000 years,
vegetation and anthropogenic soils are part of a domesticated landscape heavily influenced by
human activities, and can hardly in an economic analysis be seen as given, but are in fact the
outcome of economy, social organisation and technology.
A special question relates to the role of vector-borne diseases in Africa. They are most often
treated like given, exogenous variables in the analysis of the economy. But the reserach into
the environmental history of tsetse and trypanosomiasis shows clearly that the distribution of
tsetse can is not naturally given, but reflects the degree to which humans have cleared the land
(Giblin 1990).
Agricultural systems in Africa 1500 to 1800
The analysis of agricultural systems in Africa and their relation to the environment is based on
an ongoing project aimed at producing a series of maps covering the last millennium in which
the known agricultural history of world is made spatially explicit. Three cross-sections in time
are chosen.



1800 – before the second wave of globalization that drew large parts of the global
south into commercial agriculture.
1500 – or more precisely 1491, on the eve of European oceanic expansion and before
the Columbian exchange
1000 – a time period when African and American polities and landscapes were
distinctly different from those of the late 15th century
The project was in its design inspired by the work done by historical geographers in the US on
the precolumbian agriculture in North and South America. The perspectives outlined in the
works by Bill Turner and Karl Butzer (Turner & Butzer 1992, Butzer 1992,Turner et al. 1995)
and the three syntheses on the cultivated landscapes of different regions of the Americas
(Doolittle 2000, Denevan 2001, Whitmore and Turner 2001) formed a model for our work. In
the dissemination of that work to a broader audience Charles Mann also later showed that it
was possible to summarize the knowledge in map form (Mann 2005).
For Africa a preliminary result from this project shows that the period 1500 to 1800 implied
an intensification of agriculture in many different parts of the continent. We note terracing,
irrigation, increased investments in anthropogenic soils and intensification based on new
crops. Among the factors behind this intensification are the establishment of Portuguese
trading posts along the coast, the Atlantic trade, the American crops, and the slave trade. The
evidence for agricultural intensification is often indirect and based on the degree of
investment in terracing and irrigation. It is thus far from the quantitative measures of
agricultural productivity used by e.g. Gallup and Sachs but it may be assumed that there is a
relation between these indicators of intensity and an increased area productivity. In the
following I will analyse to what degree the development differed between climatic zones and
hence to what degree climatic differences determined African agricultural development
during this period.
Islands of intensive agriculture in the savannah regions
The localised occurrence of pre-colonial irrigation and soil-and-water conservation in the
form of terracing has, in Africa, has generally been considered an exception from an assumed
prevailing system of shifting agriculture. In a previous project we investigated and compared
some of the cases mainly in eastern Africa (Widgren & Sutton 2004). The “islands” of
intensive agriculture, were in that work, seen as signs of incipient, but halted, process of
intensification. They witness to the fact, that from the perspective of landscapes, soils and
climate, a development towards a much more intensively cultivated landscape was possible in
eastern Africa. Terracing, mulching, manuring, and irrigation was known and it can be
seriously questioned whether the often quoted environmental problems in Africa were really
the causative factor behind the slower development in Africa, as compared to similar
environments in India. In that work we tried to single out some of the factors leading to
intensification and emphasised the geographical labour division, though institutionalised
exchange. As we can understand this intensification now, it was in all documented cases
connected to a geographical division of labour – in some cases as a direct consequence of the
caravan trade in the 19th century (Baringo, Kenya see Andersson 1988, 1989) and in other
cases through institutionalised exchange within or between ethnical groups (Östberg 2004,
Loiske 2004). The relations between, on the one hand trade and exchange, and on the other,
investments in landesque capital has been further elaborated for four contrasting cases in
Tanzania (Håkansson & Widgren 2007). An overview of similar islands of intensification in
Western Africa and in the Sahel zone seems to confirm this conclusion (Widgren 2010).
These intensive agrarian systems, from the Dogon and the Kassena in the west to the Nuba
hills (Kordofan) in the east, have mainly been described as the outcome of the slave raiding
from the 15th century onwards. In the old German and French literature they have been
described as the remnants of a paleonegritic culture, who escaped the slave raiding by
retreating into inaccessible hills or refoulés montagnards. While this interpretation is often
quoted in literature focusing on the recent development among these hill farmers, there is
surprisingly little historical and archaeological evidence for the age of the terracing and other
farming practices. After a closer scrutiny of the west African cases I concluded in Widgren
2010:_
The hill environments often provided not only shelter from invasions, but also good
conditions for agriculture. Soils are often of volcanic origin or are for other reasons more
fertile than on the surrounding plains. Several sources of water are evident, and it has also
been argued that the hills receive higher precipitation and that the rains are also more
regular (Dresch 1952:6; Froelich 1968:60; Netting 1973:226; Beek & Avontuur 2005:72).
It has also been argued that the hills provided healthier environments (Eggon in Nigeria:
Dorward 1987:204). As Straube argues, it was rather the extraordinarily bad conditions
for agriculture on the great plains of the continent that led to a concentration of farmers in
hilly areas (Straube 1967:209). The argument that the hills, from an agricultural
viewpoint, offered fewer possibilities than the plains (which is one part of the siege
hypothesis) can thus be questioned. However, as Netting points out, a more detailed
analysis of labour productivity versus land productivity needs to be taken into account
(Netting 1973:43).
-
---On the basis of evidence from the Mandara Mountains and the Tangale Waja uplands, it
seems probable that in 1500 and well before, many of these hills were indeed settled and
farmed. Further, evidence suggests that they offered some environmental advantages over
the surrounding savannah lowlands. Higher precipitation and, often, good volcanic soils
offered possibilities for those who were ready to embark on labour-intensive agriculture.
Terracing, mulching, manuring and other intensive farming practices in these areas might
therefore have their origin in times well before slave raiding, although the extent of
terracing at that time cannot be established. (Widgren 2010)
Intensification in the west African plains
In the same article and in a more recent one on the connection between slavery and
agricultural intensification (Widgren 2012) I have also described the parallel intensification in
the plains of the savannah zone:
Farming in the closely settled zones around the Hausa capitals is well described from the
mid 19th century. Barth travelled in the 1850s through intensively cultivated fields of
millet, sorghum, cotton and indigo (Barth 1859). From later evidence we know that
manuring, stubble grazing, intercropping, ridging and irrigation were part of the system
(Raynaut 1989; Swindell & Iliya 1989). To what extent such farming practices were
present at the beginning of the 19th century has not yet been proven. The answer might
lie in new methods of investigating the age of anthropogenic soils in such areas (Adderley
et al. 2004 and personal communication).
The intensive farming, mulching and manuring that occurred in these areas and more
generally in the semi-arid belt from Senegal to Nigeria (e.g. Mossi in Burkina Faso) led to
the development of what has been characterised as ring cultivation or the infield–outfield
system (Fussel 1992; Prudencio 1993). It is striking that this type of labour-intensive
farming occurs in a zone where there were ‘predatory’ slave-raiding and slave-using
states in the 18th and 19th centuries. We know that slaves played an important role in
agricultural labour and that plantations with slave labour were in existence (Lovejoy
1986). However, to my knowledge, the possible role of slave labour as a force behind this
intensification has not been explored in more detail.
When the perspective is broadened from looking only at terraced agriculture in hilly
areas, it thus becomes evident that different labour-intensive farming practices, leading to
investments in land, were practiced in both hills and plains in West Africa during the 19th
century and earlier. A previous approach focussed on intensification as an outcome of the
retreat of decentralised societies into hills and mountains, but this view is clearly
challenged by the fact that intensification also occurred on the plains and in areas
dominated by stratified social organisation and predatory states. It seems as if the labour
mobilisation required for intensive agriculture was achieved at both ends of this social
continuum. This idea supports the notion of complexity in the relationships between
intensification of agriculture and structures of power (Widgren 2010)
Intensification in the tropical zone
In most maps of African agricultural systems a large zone of central and equatorial Africa is
usually characterised as based on shifting agriculture. From the overviews by Allan (1965)
and Miracle (1967) we however know that, throughout that region, extensive forms of shifting
cultivation often coexisted with horticulture close to the settlements. For some of the crops,
there were also variations the form of the forest based shifting cultivation so that a more
labour intensive kind of shifting agriculture, with mounding and composting, was practiced.
With the arrival of the American crops, especially cassava, but also maize, these labour
intensive practices seem to have increased in importance. For the central parts of the Congo
basin Vansina has shown how the arrival of American crops combined with the expansion of
the Portuguese trade led to localised areas of a more intensive agriculture (Vansina 1990).
According to Vansina the demand for foodstuffs to feed the slave trade led to this
intensification, first by slave villages and farms and later on by the introduction of the new
high-yielding American crops. Of special importance was the manioc/cassava because of its
storing capacity. Intensive and labour demanding cultivation of cassava then developed
among the main trade routes and their immediate hinterland. Vansina is, however, not very
precise about the chronology of these processes.
A contrasting view, of the role of trade versus the role of an indigenous agricultural revolution
in the spread of cassava in central Africa, is presented by Achim van Oppen. (1999). He
shows that the remote interior of central Africa took up that cassava cultivation well before it
was accepted at the coast. It was present in the Lunda empire in 16th century, and reached the
upper Zambesi in 17th century. von Oppen categorises the adoption of cassava in these areas
as an indigenous revolution. He shows how it enabled an increased permanency of fields, and
hence a reduction in the labour for clearing new land. This had effects on the gendered
division of labour, with increased workloads for women in the planting, mounding and
composting and reduced male labour in clearing new lands (Oppen 1999).
Intensification in the temperate zone
In the temperate zones in Southern Africa two cases of vast areas of terracing are known in
Nyanga (Zimbabwe) and Bokoni (South Africa). This terracing exists today only as
archaeological features and the full context of these areas of agricultural intensification is
insufficiently known (Soper 2002, Delius and Schoeman 2008, Delius and Schirmer
2014)).They both roughly belong to the period 1500 to 1800 and have many traits in common
with the terraced areas in the savannah zone of West Africa and the islands of intensification
in eastern Africa.
Conclusion
By viewing these different case of agricultural intensification during the period 1500 to 1800
from the viewpoint of different climatic zones it becomes clear that there is no clear
correlation with climate. Intensification occurred in different environments and it is not
possible to single out one climatic zone which was more favourable for this intensification.
The intensification took different forms in different climatic zones in terms of crops involved,
farming practices, degree and character of investment in the land and degree of integration
between livestock and arable farming but the driving forces were more likely the political
institutions, involvement in Atlantic trade, and in institutionalised exchanged with other
groups, rather than environmental factors. The different pathways towards intensive farming
also bear witness to the possibilities for the development of a more productive agriculture in
Africa, regardless of climatic zones and regardless of environmental limitations that in some
analyses have been used to explain Africas lack of development.
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