Ideas about the origins of agriculture have for a long time been pervaded by some measure of ethnocentricity. The tendency was (and sometimes still is) to think that a 'Neolithic Revolution', as defined by Gordon Childe, occurred in an agricultural and pastoral cradle in the Near East, and that this was not simply the birthplace for the cultivation of major cereals like wheat and barley and of animal husbandry (goats, sheep and later cattle), which are the very foundation of western material civilization, but also the genesis of civilization itself, at any rate so far as the Old World was concerned. It is no doubt true that archaeological research after the Second World War and especially during the last twenty years has to some extent modified this narrow and somewhat self-centred point of view.
Recent research has confirmed the importance of the Fertile Crescent in the history of world agriculture, but it has also thrown light on the role of other regions in this major change in the life of man, a change to the production of foodstuffs which previously had been merely collected from the natural environment. The result has been a clearer appreciation of the significance of agricultural inventions and plant domestication in America and of the relatively earlier development of a cradle of agriculture in tropical southeast Asia and, lastly, of the contribution of Africa to the history of world agriculture.
Already, however, nearly half a century ago, the celebrated Russian agronomist and geneticist N.I.Vavilov posited the existence of centres in Africa where cultivated plants could have originated, and later one of his assistants, A. Kuptsov, demonstrated that such centres had, in fact, existed. A few years later, one of the authors of this chapter plotted in detail the situation and number of these centres of origin and described their role. However, colonialist prejudices, allied to ignorance about many African cultigens and, generally, about the prehistory of the continent, led to a long period when the participation of Africa in developing agricultural techniques and resources was either played down or disregarded altogether.
This situation has now radically changed and the last few years have seen the growth of a keen interest in the origins of African agriculture, witness, for example, the essays published in 1968 in 'Current Anthropology' and the large number of comments that they aroused. We must also mention the studies put together by J.D.Fage and R. A.Oliver and, still more recently, the contribution of W.G.L.Randies to the history of Bantu civilization. But before attempting a brief account of the state of our knowledge of the agricultural prehistory of Africa, w e must describe the ecological setting into which it fitted.
Natural environments and the origins of African agriculture
It is obvious that the origins, development and diversity of agricultural techniques must be closely related to aspects of the natural environment such as the climate, the water resources, the geographical relief, the nature of the soil and of the vegetation, the types of plants originally utilized, and the nature of foodstuffs they yielded, and so on. However, these elements, important and even predominant as they are in the raising of plants and stock were not the sole agencies at work. There was also the influence of the prevailing cultures and civilizations.
Even in pre-agricultural times and when agriculture was just beginning, man had carried with him in his migrations implements, techniques, modes of understanding and interpreting the environment, and methods of manipulating and using space. He also took with him a whole range of attitudes and of behaviour that had grown out of his relationships with nature in his original habitat. Thus, at a time when Europe was barely emerging from the Palaeolithic, the cultivation of plants and the raising of livestock were already established in the Near East, where the first cities were beginning to appear, and it was the Near East which introduced to a somewhat backward Europe those technical inventions which, with their attendant attitudes, made possible there also a 'Neolithic Revolution' based on agriculture and stock-breeding.
Similar migrations or exchanges took place in Africa, as elsewhere, as a result of population movements within Africa and between neighbouring continents. It is essential, however, to grasp the implications both of the inventions of agriculture and stock-herding and of the domestication of plants and animals. Man passed from mere food collecting (gathering, hunting) to artificially producing (cultivating, rearing). Thus, progressively and partially, man began to free himself from the constraints of the ecosystems to which he belonged and in which, until he began to control agriculture and stockraising, he led more or less the same passive or bio-cenotic life as other living organisms following the normal course of natural processes.
Thus the introduction of agriculture and stock-raising was a fundamental change which permitted human beings to adapt to various natural environments and made it possible to change biological processes in order to produce more or something different from what they would have done by themselves. Man's new role of cultivator and stock-breeder also caused very considerable changes in the natural environment as well as in quantity and quality of the food produced. Nevertheless, in spite of his mastery over some elements of his natural environment, m a n was not able to free himself totally and immediately from all the constraints they imposed. We must therefore consider the environmental features which played an overriding role in agricultural prehistory and history in Africa, and so we need to sketch an environmental map of the continent. We find that it is divided into wide latitudinal bands which are ecologically distinct from each other and which lie symmetrically north and south of the equator.
As was pointed out by Randies (1974), some of these bands acted as barriers to north-south migrations. The barriers were the Sahara, the great equatorial rain forest, the Tanzanian steppe and the Kalahari desert. But other bands provided spaces, or convenient pockets, into which these currents or population movements could flow, for example, the northern and southern savannahs. Randies, however, also pointed out that none of the barriers were absolutely impenetrable; the Sahara and the great equatorial forest, for example, contain obvious evidence of some migration of peoples.
Latitude is not the sole factor roughly marking off the major ecological zones of Africa. Geographical relief and so also altitude enter into the picture as well, witness the Zaire-Nile axis which separates the East African highlands from the West African peneplain while the latter itself is bisected by a minor axis of up-thrust between Principe island and Chad. There are therefore exceptions to this latitudinal zoning of the African continent, the most important of which is perhaps that of the highlands already mentioned extending, parallel to the Rift valley, from the north of Lake Victoria to the Munchinga hills and which, to cite Randies again, acted as a narrow and safe corridor through the equatorial barrier (Fig. 27.1). There is also the Ethiopian massif, the role of which in the origin of African cultivated plants will be described later.
If at this stage we put together the various elements of the picture, extremely summary though they may be, we can see Africa as consisting of an almost semicircular zone of savannah and steppe in the north, the east and the south enclosing a core of equatorial forest, and then still further north and south, two arid zones - the Sahara and the Kalahari - and lastly, to furthest north and furthest south, two narrow almost homo-climatic zones which, to simplify a great deal, could both be described as Mediterranean in climate even though there are certain ecological peculiarities to be found in the extreme south of Africa (Fig. 27.2). Moving outwards, then, from the equatorial forest heart of Africa and leaving aside the coastal regions, we can draw a graph from the extremely humid to the extremely dry, from the generalized ecosystems of the tropical rain forest type to the more specialized ecosystems of the savannah, steppe and desert scrub types.]
With regard to deserts, and more specifically the Sahara, it may at this point be recalled, even though it is now a sufficiently well-known fact, that it was not always the desert that it is now. Agriculture and stock-raising were carried on there, and a number of writershave suggested that cradles of agriculture and animal husbandry are to be found in the Sahara. Returning, however, to our ecological map of Africa, we can assume that in pre-agricultural times food-gathering and hunting similar to those still used today by the Pygmies were practised in the generalized ecosystem of the great tropical rain forest, whose food resources, both animal and vegetable, are as varied and abundant as the constituents of their biocenoses. Given the food resources available to Pygmy bands and the density of population in the forests, it is clear that they can obtain the food they need without undue effort or anxiety.
The same is true of the hunter-gatherers in the more specialized ecosystem of arid and sub-arid regions, for example, the Kung San of the Kalahari studied by J.B.Lee. For these people the food available is less varied and, because of wide seasonal variations in rainfall, tends to be restricted to areas near water supplies.
Returning to Africa's pre-agricultural past, we may note that the humid phase known as the Makalian (5500-2500 before our era) which followed the Pleistocene made contacts rather easier between the Mediterranean coast and the regions south of the Sahara, while the increase in the level of water courses and lakes, even in the heart of the continent, helped fishing to develop and brought some degree of settlement among the populations which resorted to it. Both of these conditions favoured the gradual transition to agriculture. Migrations from the Near Eastern and Mediterranean cradles of agriculture which took place at this time no doubt accelerated the process.
From the end of the Pleistocene, that is, between 9000 before our era and the beginning of the Makalian, there seem to have been some places where the kind of food suitable for gathering grew in great abundance and this doubtless encouraged early man to concentrate in them. The forest-savannah borderland on the edges of the equatorial forest, the East African grassland plateaux, the waterside of lakes and major rivers, such as the Nile, as well as the coastal regions of the north and south come into this category.
These transitional zones, and especially the forest-savannah borderland, possessed all the characteristics required for agricultural development and, much later, not surprisingly, for the growth of a number of African civilizations. Randies remarks in this connection that it is 'at the margins of the two savannahs (Sahel and forest fringes) that are to be found the most prestigious of the Bantu civilizations'. We should now consider in some detail the possibilities for plant domestication that were available in Africa, for we must not forget that in the logic of ecology it is the plants which are the primary producers.
The African origin of some cultivated plants
It is only comparatively recently that interest has been focused on the origin of cultivated plants. If the remarkable work by A. de Candolle, published in 1883, is excepted, it is only with the work of the Soviet geneticist N.I.Vavilov and his team beginning work soon after the October Revolution in 1917 that a global approach was made to this question of fundamental importance in the history of man, and that man's attempts to use his environment and its resources were studied.Vavilov's point of departure was the variations observed in cultivated plants and, by combining a systematic analysis of botanical and phyto-geographical data with agrobotanical inventories and genetic studies, he and his assistants were able to point to eight regions where cultivated plants first emerged. These eight regions included three secondary centres, of more local importance.
Only one of the main centres, the Abyssinian, is situated in Africa, though another, the Mediterranean, affects part of the African continent (North Africa and Egypt), and also shows affinities with the vastly important Near Eastern centre of origin where, as we have already said, the major cereals (wheats, barleys, ryes) appeared in addition to other cultivated plants. With regard to Africa, Vavilov's conclusions represent a considerable change from those of Candolle, who recognized only three primary centres of origin for agriculture and the domestication of plants: China, South-East Asia (with an extension to Egypt) and America.
Vavilov's contribution to the understanding of the theory of the origin of cultivated plants was also of the highest importance, because he established the need to distinguish between a centre of primary mutation, where a very great diversity in any particular plant is combined with continuing dominant characteristics, and, on the other hand, sub-areas of secondary mutation which show many recessive characteristics which were masked in the centre of primary mutation. When centres of mutation are found closely associated in the same area they are said jointly to constitute a 'cradle of agriculture', and its existence is usually an indication that a civilization has been at work for a long time, altering and domesticating the plants required by that society. It is important to stress the point that the botanical place of origin of a cultivated plant species is not necessarily the same as the area in which it was first adapted by human intervention for man's own use.
So, one often has to distinguish between the place of origin of the wild parent of a cultivated species and the place where the plant emerged in an altered form after being domesticated and subjected to selection by man. This last has a simple explanation. In the long years of plant-gathering a wild parent must have been frequently carried away from its original habitat. One of the present authors has been able to complete Vavilov's picture by demonstrating that in addition to the Abyssinian centre and the African portion of the Mediterranean centre, there existed also a West African centre and an East African one, this latter being possibly an extension into the equatorial highlands of the Abyssinian centre. We can summarize the situation as follows:
The Mediterranean centre. The African portion of this centre includes the group of cultivated plants n ow characteristic of Mediterranean regions, such as cereals, especially wheats and barleys, and leguminous plants with edible seeds (Cicer, Lens, Pisum, Vicia) which were also developed in the Near Eastern centre. We also find here common Mediterranean cultivated species such as the olive tree (Olea europa L.) and the carob or Mediterranean locust tree (Ceratonia siliqua L.). However, some of the plants are proper to Africa, like the argan tree (Argania sideroxylon Roem.) from Morocco which yields oil and gum.
Egypt, whose links with the Near East are obvious and whose influence in agriculture and stock-breeding in North Africa is so important, belongs to this centre. In Egypt, and also Syria, the berseem or Alexandrian clover (Trifolium alexandrinum L.) was developed and proved of great economic importance. Although this African portion of the Mediterranean centre did not play a direct part in the development of agriculture in tropical Africa, it did profoundly influence the Sahara during the period when the climate there was favourable to cultivation and stock-raising.
The Abyssinian centre has, in the cultivated species it produced, affinities with the Near East centre (wheats, barleys, leguminous plants like Cicer, Lens, Pisum, Vicia) and also with some found in African centres proper such as sorghum which will be dealt with later. It seems evident that plants originating in Asia passed into Africa through this centre. However, this Abyssinian centre also developed some characteristic cultivated species, among them the Arabian coffee shrub (Coffea arabica L.), the Abyssinian banana tree (Musa ensete, I.F. Gmelin) the teff grass (Eragrostis abyssinica Schrad.) and the niger with oleaginous seeds (Guizotia abyssinica, L.f. Cass.).
The East African centre is characterized by a number of varieties of sorghum including Sorghum verticilliflorum Stapf, and various penicilliary millets such as the Eleusine coracana Gaertn. and various sesames.
The West African centre. Here we find the origin of various types of sorghum deriving from Sorghum arundinaceum Stapf.; of penicilliary millet like Pennisetum pychnostachyum Stapf, and Hubb. and P. gambiense Stapf, and Hubb.; as well as digitary millets including ibura (Digitaria ibura Stapf.) and fonio (D.excilis Stapf.) and several rice varieties which will be referred to below. In this centre we can distinguish two main ranges of development, the tropical and the sub-equatorial. Within the tropical range there are several subdivisions (the Senegambian, the central Niger, the Chad-Nilotic), each of them producing characteristic cultivated plants, principally cereals but some tuberous (Coleus dazo Chev. especially) and some oleaginous such as Butyrospermum parkii (Don.) Kotschy (known to botanists also as Vitellaria paradoxa Gaertner).
To the sub-equatorial range belong especially the yams (Dioscorea cayenensis Lam., D. dumetorum Pax., D.rotundata Poir.), oleaginous plants Elaeis guineensis Jacq., Telfairia
occidentalis Hook,f.) and stimulants (Cola nitida A. Chev.). This centre actually extends itself into central Africa, as do the areas of diffusion of certain kinds of plants mentioned above (Cola, Coleus, Elaeis). The earthpea or Bambara groundnut (Voandzeia subterranea Thon.) and the leguminous African geocarp (Kerstingiella geocarpa Harms.) also originated in the West African centre.
In the view of the present authors, there originally existed to the immediate east and south of the equatorial forest a belt with a complex of cultivated species similar to the one found in the West African centre and which roughly followed contours of the forest belt, skirting in the process the East African centre and thus practically co-extensive with the intensive gathering zone of the forest perimeter described above. All these considerations lead us to suppose that a number of cradles of agriculture existed in Africa which we can list as follows (Fig. 27.3).
(1) The Afro-Mediterranean cradle, stretching from Egypt to Morocco, which influenced the development of agriculture and pastoralism in the Sahara and which also acted as a channel of exchange with the Near Eastern cradle through Egypt.
(2)(a) The West African cradle, with its tropical and sub-equatorial sectors,
(b) The Nile-Abyssinian cradle in the east, with two sectors: the Nilotic and the Abyssinian.
(3) The Central African cradle.
(4) The East African cradle to the east of the Central African cradle and extending west to Angola.
Further to the south, it appears that food gatherers, doubtless provided with adequate resources, but also protected by the aridity of the Kalahari, managed for a long time to resist the penetration of agriculture and pastoralism from the cradles described above and, more particularly, from the East African cradle. The concept of'cradles of agriculture' has the disadvantage of suggesting that the prehistory and history of agricultural development proceeded in a patchwork pattern. However, in the light of what has already been said, we think it possible to present a more coherent general picture.
In the central core of forest, there was a generalized ecosystem out of which was developed a 'centre of horticulture' (a term which we think preferable to the unsatisfactory term 'centre of vegeculture' proposed by R.J.Braidwood and C. A. Reed). But in the forest conditions, gathering was still sufficiently productive to allow this to continue. It should be noted that the range of plants from this centre which could usefully be domesticated was less wide than the range found in the wet tropical forest centres of Asia or America. Secondly, there was the savannah around forest fringes providing a more specialized ecosystem which became an agricultural centre for the cultivation of cereals, and which extended from West to East Africa and south towards Angola.
In North Africa along the Mediterranean the cultivation of cereals spread from Mesopotamia through Egypt. It also penetrated into the Sahara at a time when conditions were suitable, and this fact goes a long way towards explaining some diffusions towards the south of the present desert as well as others in the opposite direction from sub-Saharan Africa. The influence of Mesopotamia can also be seen in the Ethiopian highlands, which however also share some affinities with the agricultural centre of the savannahs and steppes as well as possessing their own cultigenic characteristics.
A horticultural centre differs from a centre of agriculture in the preponderance of tuberous plants, and in the method of cultivation which belongs rather to the garden-orchard (the hortus of the forest and its borders) than to the field (the ager of the savannah and the steppe). In the African continent as a whole, agricultural implements consisted principally of the hoe and the digging stick, with their variations, but a primitive plough introduced through Egypt and Ethiopia made an inroad into part of the centre of cereal cultivation.
The cultivation of sorghum and rice
In contrast to the horticultural centre of the generalized ecosystem of the forest belt, the African agricultural centre, within the relatively specialized ecosystem of savannah and steppe, is characterized first by the use of cultivated plants reproduced by the sowing of seeds and secondly by the importance of cereals in the food complex of the population. Agricultural systems of this kind cultivated plants en masse as distinct from the cultivation of single plants that is characteristic of the horticulture found in the forest belt. The agricultural civilizations no doubt extended their cultivated fields at the expense of the forest as they came into contact with it in the course of their territorial expansion and this tended to increase the extent of the savannah.
In ecological terms, these civilizations imposed some degree of specialization on ecosystems that were originally generalized in their nature and in this way subjected the natural environment to their techniques, or rather to their conception of what the environment should be. But there were failures as well as successes in this penetration of agriculture into the forest milieu: for example, cereals might have been abandoned in favour of food crops which were more characteristic of the forests and even - the possibility cannot be ruled out - the adoption of plant-gathering as the means of subsistence by savannah peoples normally agriculturists, who had been obliged to take to life in a forest environment.
The fact, however, remains that the cultivation of cereals is the main characteristic of steppe and savannah agriculture. Among these cereals one in particular - sorghum (Sorghum spp.) or great millet - appears as the characteristic cultigen throughout the area of this agricultural centre though other varieties of different origin are also found. The origin of the various varieties of sorghum was for a long time the subject of conflicting views, but it seems that the cereal sorghums did indeed originate in Africa and that in fact they did have a number of independent points of origin within the African agricultural centre. The wild variety Sorghum arundinaceum Stapf., which originated in the wet tropical zone running from Cape Verde to the Indian Ocean, gave rise to the group of sorghums cultivated in West Africa: S. aterrimum Stapf., S. nitens Snowd., S. drummondii Mill sp. and Chase, S. margaritiferum Stapf., S. guiñéense Stapf., S. gambicum Snowd., S. exsertum Snowd.
The wild variety S. verticilliflorum Stapf., which originated in the area of East Africa from Eritrea to south-east Africa, gave rise to two groups of cultivated sorghums: the south-east African or the Kafir sorghums: S. caffrorum Beauv., S. coriaceum Snowd., S. dulcicaule (sweet sorghum), and the Chad-Nile type usually found from the Nigerian Sudan to Eritrea: S. nigricans Snowd. and S. caudatum Stapf. The wild variety S. aethiopicum Rupr., which originated in Eritrea and Ethiopia, gave rise to S. rigidum Snowd. found on the Blue Nile, S. durra Stapf, cultivated from Chad to India and in all semi-desert types of country, S. cernuum Host., S. subglabrescens Schw. and Asch. found in the Nilotic regions, and S. nigricum cultivated in the central Nigerian delta.
In the central River Niger sector of the tropical section of the West African cradle a special cultivated sorghum, S. mellitum Snowd. var. mellitum Snowd., is used for making an alcoholic drink because of its rich sugar content. Other sorghums are also used for making 'millet beer'.
There are cross-relations between these various groups of cultivated sorghums, as is witnessed by the existence of S. conspicuum Snowd. (found from Tanganyika to Zimbabwe and Angola) and S. roxburghii Stapf, (found in Uganda, Kenya, Zimbabwe and South Africa), which seem to have arisen from crossing between sorghums, some of which were related to S. arundinaceum and others to S. verticilliflorum. Of these sorghums, S.durra deserves to be noted because of its distribution over the whole area from the eastern Sudan to Asia Minor and India and from Mesopotamia to Iran and Gujarat.
Enough has been said to indicate the importance of these cereals in the plant economy of the agricultural centre of the African savannahs and steppes of Africa. Moreover, this importance transcends the limits of the continent since some types of sorghum domesticated here spread very early to other regions of the world. So it would seem better to see Africa as having both a number of cradles of agriculture and a mosaic of centres where cultivated plants originated, some of which became of economic importance on a global scale. Africa was the source of other cultivated species, not least rice, which was developed from indigenous varieties. These varieties were found in the West African cradle and, more precisely, in the central River Niger sector, a centre of primary variation, and in the Senegambian sector, a secondary centre.
In classical times, Strabo had referred to the cultivation of rice in Africa and in the fourteenth centry Ibn Battuta mentioned that rice was produced on the Niger. But this evidence was often ignored and it was for a long time believed that rice cultivation in Africa began with the introduction of Asian rice (Oryza sativa R.). It was only about 1914 that the existence of a specifically African variety of rice was recognized (O. glaberrima Steudel). This has rigid, upright panicles and brown or red caryopses, a variety which can be gathered wild but which can also be cultivated and which seems to be related to the O. breviligulata A.Chev. and O.Roer found in much of the African tropics.
This African rice provides a good illustration of the theories of N.I.Vavilov. The Soviet agronomist and geneticist established that a wild parent plant required a very extensive territory if a cultivated species were to emerge. In the case of African rice there was a maximum possibility of variation with a preponderance of dominant characteristics in the central delta of the Niger (the primary centre) and a variety of species with recessive characteristics in upper Gambia and in Casamance (the secondary centre). Moving outwards, therefore, from the central delta of the Niger, the cultivated varieties of African rice spread in West Africa to the Guinea Coast. The gathering of the wild variety O. glaberrima was certainly an extremely ancient practice, and this wild cereal must have been plentiful in those relatively intensive food-gathering centres where conditions favoured the first domestication of plants. It may therefore be supposed that the domestication of African rice occurred at least as long ago as that of the other African cereals.
By R.Portères and J. Barrau as 'Origins, development and expansion of agricultural techniques' in the book " GENERAL HISTORY OF AFRICA I, J. Ki-Zerbo editor, Heinemann Publishers (London), UNESCO (Paris) and University of California Press (USA), 2000, excerpts from pages 687-699. Digitized, adapted and illustrated to be posted by Leopoldo Costa.
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