The South Atlantic Columbian Exchange
In his classic 1972 book, The Columbian Exchange, Alfred W. Crosby Jr. assesses the biological and cultural consequences of the introduction of new species into transatlantic environments. From 1492 on, different species of animals, plants, viruses and bacteria were exchanged between the Old and New Worlds following their human symbiotic companions. The consequences of these exchanges for human history were manifold — from the decimation of the majority of Americas’ indigenous population by Old-World germs in the early modern period to a global agriculture revolution that changed the patterns of food and drug consumption, textile production, and set the basis for the European colonization of the Americas. If one were to plot, on a world map, the ports of origin of these invasive species and the transatlantic regions to which they were first introduced, one would be able to visualize the many threads connecting not only Europe, but also Africa, to the Americas in the early modern period. These later South-Atlantic transfers demonstrate that the importance of the transatlantic exchange is not reducible to a matter of European “ecological imperialism” in the neo-Europes of the temperate New World. A tropical exchange also helped to shape the food and agricultural systems of populations living outside those areas of temperate climate.
In the case of sub-Saharan Africa and the Portuguese America, these transatlantic species were carried through the sea lanes set by Europeans in their establishment in South Atlantic shores, and were also part of one of the biggest and longest transatlantic flux of human population, that of the African slaves. In the late sixteenth century, the slave trade became the main maritime pathway for the tropical exchange of biological species, but before that, Portuguese sailors were already using the South Atlantic’s two coasts as a stopping point in their travels to and from the Indian Ocean. The aim of this paper is to directly contextualize the Columbian exchange in the South Atlantic world during the early modern period. Exactly when, where, and how did the exchange described by Crosby occur in the tropics? How did the introduction of these new species follow the spatial connections established mainly by Europeans between Brazil and Africa?
Although the connections between Portuguese America and sub-Saharan Africa are a well-covered topic in the literature on the Atlantic World, little attention has been focused on the issue of a South Atlantic Columbian exchange. Crosby himself does not spend much time on Portuguese colonies, even though he reserves a substantial portion of The Columbian Exchange for dealing with Spanish America. Other authors who focus more specifically on the transatlantic transplantation of agricultural systems that followed the slave trade also fall short in studying these phenomena in the South Atlantic region. One example of this omission is Judith A. Carney’s Black Rice, a book that proposes to be the history of the “African origins of rice cultivation in the Americas”, but which, in fact, focuses mainly on North America (particularly North Carolina). Portuguese America was one of the first destinations for African slaves in the sixteenth century, and Brazil received the largest amount of African slaves during the early modern period (Table 1). Also, Portuguese and Brazilian ships were responsible for the biggest share of slave transport between 1500 an 1800 — 39 percent of enslaved Africans passed through the Middle Passage in a ship with a Portuguese flag. British ships came in second, with 34 percent. Moreover, a share of these Portuguese-flagged trade was increasingly in the hands of entrepreneurs located in Brazil and therefore, it is reasonable to call this trade a Luso-Brazilian one. This considerable Luso-Brazilian slave trade cannot be explained away by the classical models of triangular trade connecting Northwest Europe, North America, and the Caribbean and, therefore, it is necessary to recognize the existence of a South-South connection linking Portuguese America and Africa. Therefore, it is reasonable to assess the biological exchanges between Africa and the Americas by giving special attention to the two Portuguese colonies of Brazil and Grão Pará and Maranhão. This is the path we will follow in this paper.
Table 1. Disembarkation regions of African slaves between 1500 and 1800.
Number of Slaves
|Mainland North America||
|Danish West Indies||
Source: The Trans-Atlantic Slave Trade Database, available at <http://www.slavevoyages.org/>, accessed May 9, 2011.
Due to the limited scope of this paper we will focus on only one of the biological kingdoms — that of the plants. Vegetal species comprise the bulk of the biological exchange between Brazil and Africa. In the present days, there are not many animals or “germs” other than malaria and the guineafowl that might have been introduced from Africa to South America, syphilis being arguably the only non-plant biological transfer in the opposite direction. Therefore, three staple crops will be at the center of this paper: from Brazil to Africa, manioc and maize, from Africa to Brazil, African rice. Varieties of manioc and maize are main staple food in contemporary Africa, and the Asiatic rice (analogous to the African rice) is important in Brazil in the present day. The longue durée role of transplanted crops attests to the importance of tropical South Atlantic connections in the early modern period. In the African continent, manioc is consumed as a chief staple in most areas of a region delimited by the Sahara desert at the north and the Zambezi River at the south, between 13° N and 18° S. In the last decades, maize has become the most produced grain in the African continent, and is grown from Morocco to South Africa. In contrast to industrialized countries, where the majority of the maize produced is used as livestock feed or industrial raw material, in Africa 95 percent of the grain is destined to human consumption. At the other side of the Atlantic, Brazil was among the ten major producers of rice in 2008, and rice and beans has been the most common staple food in most parts of Brazil since the early 20th century. Beyond these three crops, several other species of plants crossed the South Atlantic — bananas, coconuts, and sorghum coming from Africa, and pineapples, guavas, chili peppers, and sweet potatoes from Portuguese America. These other species will also appear in this paper, but our main focus is on manioc, maize, and rice.
Manioc (Manihot esculenta), also known as cassava, is a tropical root that was consumed as staple food in most parts of Portuguese America from the sixteenth to the eighteenth centuries. It was and still is today mainly consumed as flour and, in the plantation zones of colonial Brazil, third-part farmers grew the root to supply bigger sugarcane plantations. In the sixteenth century the Portuguese settlers used indigenous slave labor in both manioc and sugarcane plantations, but, by the end of the century, overseas African slaves started to substitute the Indians as a source of coerced labor. Manioc flour was one of the main items used by Luso-Brazilians in exchange for African slaves in West Central Africa. However, it took some years for manioc cultivation to be transferred to the other side of the Atlantic. In its more common variety, manioc is poisonous, and the Portuguese and Africans in Brazil employed Indian techniques to extract the poison from the plant before the fabrication of the flour. This complication can explains why it took longer for manioc to be introduced in African than other American crops, like maize.
By 1600, manioc flour was already a common staple food in the areas of the West Central African coast dominated by the Portuguese. In 1592, Brazilian Jesuits exported manioc flour to missionaries in Luanda in exchange for slaves. In Angola, manioc flour was known as farinha do Brasil (Brazilian flour), in contrast to the farinha da Europa (European flour), which was probably wheat flour. Luiz Felipe de Alencastro posits that manioc brought from Brazil started to be grown by the Portuguese in the Island of São Tomé sometime between 1600 and 1620. From there, it started to be planted in the outskirts of the Pinda port, in the Kongo kingdom, in 1625, and from there it went to Luanda, in Angola. There, the Portuguese governor Fernão de Sousa (1624-30) proposed the growing of those crops that, prior to then, were imported from Brazil. Luanda became the main producer of manioc in Portuguese Africa in the seventeenth century. Manioc flour from Luanda was used for payment of slaves brought from interior regions and of soldiers engaged in the protection of the Portuguese factories against the assaults of the Dutch West India Company (West-Indische Compagnie — WIC). In the seventeenth century, manioc flour started to be known as farinha de guerra (war flour), in both sides of the Atlantic, revealing its major role as a staple food for the Luso-Brazilian and Luso-African soldiers engaged in both Dutch-Portuguese and intra-African conflicts. Traders from other African ports, including Pinda, went to Luanda to buy the flour. A Jesuit farm in the Bengo valley, in Luanda, was known as a major producer of “war flour” in the African coast. Once the technique of extracting the poison from the root was introduced into a few points of West Central Africa, it started to diffuse to other areas, including those not under the direct influence of the Portuguese. According to Mary Karash, by the 1660s, manioc was an important crop in northern Angola, where they borrowed preparation techniques from the Kingdom of Kongo.
Further north, in West Africa, manioc spread more slowly. Its cultivation was already established in the São Tomé Island in the sixteenth century, but it was only adopted by the continent in the nineteenth century. Karasch suggests that this was due to the more tenuous ties between the Portuguese to West Africa when compared to Angola and the Kingdom of Kongo, which resulted in the system of manioc cultivation being transplanted to these regions as late as the 1800s. After 1840s, manioc was introduced in the region by the retornados (returned ones), ex-slaves from northern Brazil who returned to the Bight of Benin. Some of these returned manumitted slaves became involved in Africa with the slave trade to Brazil, which increased in the first half of the nineteenth century despite the British pressure. After the 1870s, the advent of European neo-colonialism in Africa brought the disruption of traditional patterns of growing yams and other crops, and the manioc cultivated until then only among the retornados community filled the void and became popularized throughout the region.
In Eastern Africa, the French, not the Portuguese, were responsible for transferring manioc cultivation to the region. After 1736, bringing the crop from the Atlantic coast of South America, probably from Cayenne, they introduced it into their island colonies of Mauritius, Reunion, and Madagascar. In the 1740s the Portuguese took manioc to the coast of Tanzania and Kenya, in Zanzibar, and in the following decade they started to grow it near the town of Mozambique. William O. Jones argues that the insecurity of the Portuguese tenure in the region was due to the difficulty of introducing the manioc cultivation in the region. According to Jones, West Africa and West Central Africa, with its tropical rain forests and numerous gallery forests, is much more suitable for manioc than the wooded savannas of Eastern Africa. The biome similarities between the two coasts of the South Atlantic seemed to set the limits of the early Portuguese system of tropical colonialism based on manioc. In the nineteenth century, manioc cultivation coming from the Indian Ocean coast reached the lakes Tanganyika and Victoria. There in the upper Congo, this westward spread merged with the cultivation area from the Atlantic, which had originated in the Portuguese introduction of the tuber to West Central Africa centuries earlier. However, manioc remained an unimportant crop until as late as 1850 (except in the area of the lake Tanganyika), and it only became staple food after the European colonization in the late nineteenth century, when European officials saw the crop as a solution for feeding workers.
Zea Mays, also known as corn or maize, was already widespread in Brazil before the arrival of the Portuguese in the coast of Bahia in 1500. Sérgio Buarque de Hollanda coined the term “maize civilization” to refer to the inland hilly country of southern Minas Gerais and São Paulo, where the use of maize as staple food surpassed the hegemonic manioc. Maria Yeda Linhares divides the Brazilian territory into three areas, attributing to each a different indigenous agricultural complex that was inherited by the subsequent colonial populations. In an area extending from the Amazon basin to the arid lands of the northeast to the lowland Atlantic fringes down to the São Paulo coast, the main crop was manioc. Maize was the staple food for the Guarani and Gê populations of the highlands of southeastern Brazil. Sweet potato was staple among the peoples living in the savannas that occupy most of central Brazil. In the eighteenth and early nineteenth century, this spatial division between maize and manioc areas still existed, and it reflected the weight of the indigenous agricultural techniques and cultural norms in the colonial population until that date.
Marvin Miracle offers a theory for the introduction of maize in West Africa, proposing that it was first introduced by the Portuguese through Cape Verde around 1550. However, evidence for his hypothesis is not sound. An unnamed Portuguese pilot referred to a milho zaburro in the island of São Tomé in sixteenth century, but as the word corn in english, milho in Portuguese language is both a specific word for maize and a general term for grain. Another evidence is provided by the Dutch traveler Olfert Dapper, who in the 1660s, affirms that maize was introduced by the Portuguese into the region of Gold Coast. According to him,
“First of all rice grows there and Turkish wheat, which Indians call Mays, and which was first brought from the West Indies where it is plentiful by the Portuguese to the island of Saint Thomas and which was distributed thence along the Gold Coast for Consumption by the blacks…”
However, there is also linguistic evidence suggesting that the first grains of maize reached West Africa via Saharan trade. If that is true, it is probable that the grain reached the Gold Coast originally from the Caribbean via Spain, North Africa, and Saharan trade. Indeed, it is reasonable to consider that maize was introduced in West Africa through more than one route in different times. By the seventeenth century, the grain was widespread in the region. 
For West Central Africa, Miracle affirms that, in 1591 in the kingdom of Kongo, maize was already known as the “grain of Portugal.” Additional evidence attests the presence of maize cultivation in Northern Angola in 1600. Also, there is indication that the grain was being grown in 1571 in the island of São Tomé, and that there were plans to transplant it to Angola. Oral tradition attests to the presence of maize in the south-central Congo Basin in 1680. According to Alencastro, maize growing was introduced into West Central Africa in the second half of the sixteenth century. In 1598, the Jaga, an African society of slave hunters, already grew the grain during their raids in the Angola hinterland, following the same pattern of wandering maize cultivation presented by the warrior Tupi societies of Southeast Brazil. In 1610, the grain had spread out and was already found in Congolese and Angolan markets. By 1630, the aforementioned Jesuit farm in Luanda, besides producing “war flour” to feed Portuguese soldiers engaged in colonial wars, was also growing maize, potatoes, pineapples, and papayas from Brazil. In sum, the grain was likely introduced by the Portuguese sometime after 1490s and, citing Miracle, “[it] spread so rapidly that by 1600 it had become established as a staple six hundred miles or so inland.” In the following centuries, maize advanced upriver along the Congo. It might have reached the northern Congo Basin, in the area of Lake Tanganyika, sometime after 1830.
There are scattered records for the presence of maize in Eastern Africa (Western Mozambique in 1561, and Mozambique in 1570) but “regardless of how long maize may have been established in eastern Africa, it was little observed before the end of the sixteenth century,” affirms Miracle. For 1643, there is an account of Portuguese settlers on Zanzibar and Pemba growing maize to supply the Portuguese garrison at Mombasa. In the eighteenth century, it was recorded in Madagascar (1717). In 1750, maize, probably brought from Zanzibar, was being regularly grown in Mozambique and in 1798 it had become staple on the western coast of the Mozambique Channel. In that same year, the grain was recorded as far inland as eastern Zambia. By the end of the nineteenth century, maize was found almost everywhere in eastern Africa, except Uganda, where it seems to have been introduced in Uganda after 1863, from the coast. In Kenya, it was a staple food only on the coast, in the southeastern corner of the country, in the 1880s. In sum, for Miracle, maize was introduced to Africa in different points and times, and the Portuguese seemed to be responsible for most of these introductions.
Before the arrival of the first Portuguese in the region, West Africa already had its own species of indigenous domesticated rice, known today as African rice, or black rice (Oryza glaberrima). The glaberrima is one of the two known species of domesticated rice, the other being the common rice (Oryza Sativa), which is from Asiatic origin. When the Portuguese arrived in Upper Guinea in the late fifteenth century, they found dense African populations growing not only African rice, but also other locally domesticated crops, like yams, sorghum and millets. Given the importance of rice to these populations in West Africa, and to the existence of slave-based rice plantations in the Americas in the following centuries, a group of scholars has proposed that this African rice system was transplanted from Africa to the Americas altogether with West African slaves. According to them, the agricultural techniques, the cultural system, and the biological species (O. glaberrima) were carried by Africans to the New World. Most of these authors have proposed this “black rice thesis” to understand the role of Africans in the implementation of rice culture in North America, but recently Carney extended those claims for South America.
Carney calls the coastal region between Senegambia and the contemporary Liberia the “Grain or Rice Coast.” Rice was first mentioned by the Portuguese traveler Estevão Alfonso in 1446. From the continent, the Portuguese introduced rice into the Cape Verde islands, along with slaves, at some point before 1500. The archipelago was uninhabited before the European arrival, and the Portuguese implemented there a slaved-based system of sugarcane plantation that anticipated to the one they would introduce to coastal Brazil decades later. From Cape Verde, there are records of the exportation of rice to Salvador, in Brazil, as early as 1530. According to Carney, rice cultivation was already widespread in the Bahia region, and when the Dutch invaded Pernambuco, in 1630, the grain was a common staple for the African plantation slaves. By 1620, slave ships from Cape Verde usually stopped in Portuguese São Luiz do Maranhão, which later became the main rice-producing area in Portuguese America. Carney suggests that, in northern Brazil, the cultivation of African rice was practiced mainly by slaves as a matter of subsistence. In the 1760s, when the Portuguese government acted to implement rice plantations with the Asiatic rice in Amapá, Pará and Maranhão, it passed laws banning the cultivation of African rice. She also suggests that the Dutch might have taken the African rice know-how from Recife to Paramaribo as part of the sugarcane plantations system they implemented there in the 1660s, after they were expelled from Northeast Brazil. 
However, the black rice thesis is not a consensus among historians of the Atlantic World. Walter Hawthorne, in a recent book, has questioned Carney’s findings regarding the introduction of African rice in South America. According to him, limitations in Carney’s account call into question the plausibility of her theory. We select two of these limitations as important for our purposes. First, the arroz vermelho (red rice), or arroz da terra (country rice) that Carney identified with African rice in colonial sources could also be read as any of the several native species of wild rice known and gathered by the native Tupi peoples. Second, there were not many slaves from Upper Guinea in the Portuguese America in the sixteenth and seventeenth centuries. The majority of the African slaves in Brazil during this time came from Angola, where rice (African or Asiatic) was not known then. Moreover, by the time rice began to be planted for commercial purposes in eighteenth-century Maranhão, Asiatic rice was the species used. There is no evidence that African rice was important for the implementation of these rice plantations in northern Portuguese America. There might not be even evidence for the claim that the species was transplanted to the New World by West Africans. Therefore, for our purposes of retracing the history of a South Atlantic exchange of staple crops, rice provides the weakest evidence for such an exchange. It seems that neither the actual species of African rice, O. glaberrima, nor the Upper Guinean system of rice cultivation and consumption can explain the prominent role of rice in Brazil from the eighteenth century on.
A South Atlantic System
This South Atlantic Columbian exchange points to the fact that, in contrary to that which the critics of the myth of an early Atlantic globalization affirm, there was, indeed, a system connecting several areas of the two shores of the Atlantic. Emmer is one of the scholars who has criticized the idea of an “Atlantic System.” In his attempt to counter the claims for an Atlantic system that precedes and causes the industrial revolution, he hastily concludes that outside the “plantation zones” such a system was marginal in economic terms. However, for the most part of the early modern period, these plantation zones had, in fact, the most dynamic economies. Furthermore, in the case of the Portuguese America, the connections between Africa and Brazil comprised a major part of the Atlantic trade — one that largely bypassed the triangular trade led by England. Therefore, assessing this “Atlantic System” as the cause of the Industrial Revolution, as done by both proponents and critics of this system, is a teleological exercise that misses the study of the Atlantic connections in their own right. A more sophisticated picture of this system does not limit itself to its economic effects on European industrialization, or to the expansion of European norms and values in Africa and the Americas, as proposed by Emmer, anticipating contemporary globalization. Hence, a study of the transfer of crops and agriculture techniques between Atlantic South America and Africa helps to cast light on the importance of an Atlantic System connecting subsistence farming in both continents. The transatlantic transfers of maize, manioc, and several other plants reveals a common South Atlantic world with a core area located in the two facing coasts of the southern ocean. In the early modern period, this world centered in southern Atlantic reached as far as the Amazon waterways and East Africa. In its first century, before the increase of a slave trade connecting African slave ports to American plantations, maize was introduced to the continent through several entry ports. With the increase of the slave trade in West Central Africa and the involvement of the Portuguese in conflicts against the Dutch and African kingdoms in the sixteenth, a system based on slave labor and manioc was transferred from Brazil to Africa. The following century saw the expansion of the trade to areas in West Africa like the Gold Coast and the Bight of Benin, which might have helped to supply rice plantations in the Amazon with workers already used to rice cultivation. In sum, the two shores of the South Atlantic constituted a cohesive system that, after four centuries of shared history, with the end of the slave trade to Brazil in 1850, suddenly ended. Its last ties were severed with the return of the last manumitted slave to West Africa in the late nineteenth century.
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 In 2003, Carney did write a short article on African rice in Portuguese America, but in this article, her claims for the transfer of a “black rice” system from Upper Guinea to Brazil and Maranhão are based on disputable evidence. Her “black rice theory” is discussed later in this paper. Judith A. Carney, Black Rice, and “With grains in her hair.”
 The role of Brazilians in Portuguese Africa increased during the Dutch-Portuguese conflict in the seventeenth century. In 1648, the Dutch West Indian Company, following its policy to dominate the Portuguese overseas colonies, occupied Luanda. In the 1650s, the Portuguese crown had to rely on an expedition put forth by Brazilians in Rio de Janeiro to wage war against the Dutch in Angola. By the end of the eighteenth century a great portion of the slave trade was dominated by Brazilian capital located in Rio. See Luiz Felipe de Alencastro, O Trato dos Viventes, 218-224, and João Fragoso, Homens de Grossa Aventura.
 James McCann, Maize and Grace, xiii, 1; William O. Jones, Manioc in Africa, 3; FAO, Food and Agricultural Commodities.
 Alencastro, ibid., 91-4; Karasch, ibid., 184; John Thornton, Africa and Africans, 100-1, 115-6, 324. After manioc flour started to be produced in West Central Africa, it became less important in the exchange for slaves. Cachaça (Brazilian rum) and tobacco from Brazil took the place of manioc flour as the main South American products in this exchange. In the late eighteenth century, Luanda, with a population of two thousand people, imported 1340 barrels of cachaça per year from Brazil, 76 percent from Rio de Janeiro alone. See Jaime Rodrigues, De Costa a Costa, 112.
 Sérgio Buarque de Hollanda, Caminhos e Fronteiras; Maria Yeda Linhares, História da Agricultura Brasileira, 136-140.
 Judith A. Carney, Back Rice and “With grains in her hair”; Walter Hawthorne, From Africa to Brazil, 138-40.
 Among these species of Brazilian wild rice include O. glumaepatula, O. grandiglumis, O. latifolia, O. alta, and O. rufipogon. See Walter Hawthorne, ibid., 140-1