Tubers

Tubers are cultivated for their juicy roots. These are rich in easily digestible carbohydrates (starch and sugar) and are used both for human consumption and as animal feed. Tubers usually have more calories than grains, but often less protein, vitamins and minerals. For smallholder farmers in Africa and Asia, tubers play an important role as emergency reserves, as they can remain in the ground until harvest. In sub-Saharan Africa in particular, cassava, yams and sweet potatoes cover 20% of calorie requirements.