In Guinea-Bissau, a country on the West African coast between Senegal, the Republic of Guinea and the Atlantic, rice is the staple food. Three different rice production systems coexist in the country: mangrove swamp rice, upland slash-and-burn rice and freshwater swamp rice. The coast, deeply cut by saltwater rivers where mud and silt accumulate and in which mangrove swamps grow, has favoured the production of mangrove swamp rice. This small country with an area of 36,000km2 is, out of the 16 countries that produce rice in the West African rice belt, the one which presents the biggest cultivated area of mangrove swamp rice (Écoutin et al. 1999: 211). Out of the three production systems present in the country, the mangrove swamp rice system has the greatest productivity, reaching 3,500kg per hectare without resorting to inputs (Espírito Santo 1949). The Balanta-Nhacra3 are considered the biggest producers of mangrove swamp rice in the country. Written sources from the beginning of the seventeenth century describe the Balanta living on the margins of the Geba River, a territory which they still inhabit today, dedicating themselves to the cultivation of rice and various other cereals and livestock (Álvares c. 1615: 40). The beginning of an effective colonial occupation in the second half of the nineteenth century, greater population densities and difficulties in access to land, as well as intra-ethnic and intra-lineage conflicts in the territories that had been occupied for centuries by the Balanta-Nhacra, caused an enormous migration to the south of the country (Temudo 2009; Callewaert 2000; Drift 2000; Carreira 1961). The south (the current regions of Quinara and Tombali) was abundant in mangrove swamps which were barely used by the Nalus and Biafadas, the ethnic groups that owned the land, who practiced forest and savannah upland agriculture. Within a few decades the south of the country became the main area of rice production in Guinea-Bissau, and in 1963, the Balanta were responsible for 90 percent of the rice that entered commerce (Ribeiro 1988: 235). Their agricultural system was based almost exclusively on the production of rice and the accumulation of cattle.