Cassava is to African peasant farmers as rice is to Asian farmers, or wheat and potatoes are to European farmers (Dixon A; Intl. Inst. of Tropical Agriculture in Nigeria; personal communication). Because cassava (also called manioc or yucca, with various spellings) is drought-tolerant and its mature roots can maintain their nutritional value for a long time without water, cassava may represent the future of food security in some developing countries.
Cassava originated in the New World. Today it is a staple food and animal feed in tropical and subtropical Africa, Asia, and Latin America, with an estimated total cultivated area greater than 13 million hectares, of which more than 70% is in Africa and Asia (EL-Sharkawy 2003). Approximately 500 million people depend on it as a major carbohydrate (energy) source, in part because it yields more energy per hectare than other major crops (Table 1). Cassava is grown predominantly by small-scale farmers with limited resources in marginally fertile soils; it is resistant to adverse environments and tolerates a range of rainfall (El-Sharkawy 2003). Tapioca, a commercially important starch product common in the United States, is produced from cassava roots. Figure 1 illustrates the widespread use and daily consumption of cassava and its products.
Table 1—. Maximum recorded yield and food energy of important tropical staple crops.a
Crop Annual yield (tons/hectare) Daily energy production (kJ/hectare)
aAdapted from EL-Sharkawy (2003).
bAll grains reported as dry.
Fresh cassava root 71 1045
Maize grainb 20 836
Fresh sweet potato root 65 752
Rice grain 26 652
Sorghum grain 13 477
Wheat grain 12 460
Banana fruit 39 334