Growing in elevations up to 2000 m/asl and tolerating poor soil conditions, as well as flexible harvest dates, cassava is the small farmers crop, used for food but also a cash generator when sold for industrial starch, food starch and feed. It is often the fallback staple in times of famine. It is classified as sweet or bitter, depending on the level of toxic cyanides. Improper preparation of cassava can leave enough residual cyanide to cause acute cyanide intoxication and goiters. Nevertheless, farmers often prefer the bitter varieties because they deter pests. Measured by area and day, cassava yields the highest food energy among crops. It originated in the Americas, arriving in Africa around the end of the 16th century.
Among food crops, cassava acreage ranks only 12th in the world but 4th in sub-Saharan Africa, immediately after maize, sorghum and millet. Cassava tubers begin to deteriorate immediately after harvest and are a complete loss by day three without intervention. In some regions farmers are increasingly storing their cassava in the form of chips, which better preserves the value of the crop.
Reference to numbers/statistics are from FAOSTAT 2010 for the year 2008