After cereals, root and tuber crops - including sweetpotato and yam (in addition to cassava and aroids), are the second most cultivated crops in tropical countries. This literature review examines the environmental constraints to, and impacts of, sweetpotato and yam production systems in Sub-Saharan Africa (SSA) and South Asia (SA). The review highlights crop-environment interactions at three stages of the sweetpotato/yam value chain: pre-production (e.g., land clearing), production (e.g., soil, water, and input use), and post-production (e.g., waste disposal, crop storage and transport). We find that sweetpotato and yam face similar environmental stressors. In particular, because sweetpotato and yam are vegetatively propagated, the most significant (and avoidable) environmental constraints to crop yields include disease and pest infection transmitted through the use of contaminated planting materials. Published estimates suggest yield gains in the range of 30–60% can be obtained through using healthy planting material. Moreover, reducing pest damage in the field can greatly increase the storage life of root and tuber crops after harvest – currently losses from rot and desiccation can claim up to 100% of stored sweetpotato and yam on smallholder farms.
This review is one in a series that examines crop-environment interactions drawing on both the academic literature and the field expertise of crop scientists. Other briefs in this series include:
- Agriculture & the Environment: Overview (EPAR Technical Report #254)
- Agriculture & the Environment: Cassava Systems (EPAR Research Brief #228)
- Agriculture & the Environment: Maize Systems (EPAR Research Brief #215)
- Agriculture & the Environment: Rice Systems (EPAR Research Brief #208)
- Agriculture & the Environment: Sorghum & Millet Systems (EPAR Research Brief #213)
- Agriculture & the Environment: Wheat Systems (EPAR Research Brief #212)