The African yam bean (Sphenostylis stenocarpa) provides two consumable products -the tuber which grows as the root source and the actual yam beans which develop in pods above ground.
Many consumers worldwide may already be familiar with the tuber portion of the African yam bean plant-the American variety (Pachyrizus erosus) is harvested and sold as jicama in grocery stores. Although the two yam bean plants are related genetically, the American variety does not produce edible beans.
Grown in pockets of tropical Central, West and East Africa, the African yam bean has great potential to contribute to overall food security and improve local diets. A publication by the National Research Council notes that the tuber of the African yam bean contains twice the protein of comparable African root crops including yams and sweet potatoes and has almost ten times the protein found in cassava. Consumers can enjoy the tuber raw—it’s crunchy, juicy, and mildly sweet-and it can also be cooked like other starch staples found in Africa.
In addition, the beans contain amounts of essential proteins comparable to levels found in soybeans. And like other beans, yam beans are easily-preserved through drying. This means that the crop can provide food security to households and communities in Africa that experience seasonal or unexpected disruptions in agricultural production.
The yam bean can also improve the soil. Yam beans are leguminous, adding a natural nitrogen boost in the soil and reducing the need for fertilizers in areas where farmers cultivate it.
People also consume the leaves of the African yam bean plant. Although the leaves are not a main reason for cultivation, the fact that plant foliage can be eaten or used as fodder for livestock makes the overall value of the plant even greater.
A recent article by the International Institute of Tropical Agriculture (IITA) notes that little investment has been made to scale-up production or preserve the indigenous African yam bean seed variety. The bean is most commonly grown intercropped with yams in Nigeria and Ghana and it can grow in upland and tropical areas of the continent as well. Additional funding for research and development could provide more countries in Africa with the opportunity to fight hunger with this multipurpose crop.
Danielle Nierenberg, an expert on livestock and sustainability, currently serves as Project Director of State of World 2011 for the Worldwatch Institute, a Washington, DC-based environmental think tank. Her knowledge of factory farming and its global spread and sustainable agriculture has been cited widely in the New York Times Magazine, the International Herald Tribune, the Washington Post, and
other publications.
Danielle worked for two years as a Peace Corps volunteer in the Dominican Republic. She is currently traveling across Africa looking at innovations that are working to alleviate hunger and poverty and blogging everyday at Worldwatch Institute’s Nourishing the Planet. She has a regular column with the Mail & Guardian, the Kansas City Star, and the Huffington Post and her writing was been featured in newspapers across Africa including the Cape Town Argus, the Zambia Daily Mail, Coast Week (Kenya), and other African publications. She holds an M.S. in agriculture, food, and environment from Tufts University and a B.A. in environmental policy from Monmouth College.
