Ancient plant remains found in Kenya help explain the history of plant farming in East Africa.

Around the world, the development of agriculture marked a massive leap in the social and cultural development of humanity.

Eastern Africa is a region long thought to have been important in the development of early farming.

“There are many narratives about how agriculture began in east Africa, but there’s not a lot of direct evidence of the plants themselves,” says Natalie Mueller, an assistant professor at Washington University in St. Louis and co-first author of a new study published in the Proceedings of the Royal Society B.

New evidence found during an excavation at the Kakapel Rockshelter in the Lake Victoria region of Kenya changes that.

“We found a huge assemblage of plants, including a lot of crop remains,” Mueller says. “The past shows a rich history of diverse and flexible farming systems in the region, in opposition to modern stereotypes about Africa.”

The site has been a Kenyan national monument since 2004. It includes rock art and other archaeological artefacts reflecting more than 9,000 years of human occupation.

Mueller’s team performed radiocarbon dating on the plant samples, finding remnants of cowpea dated to 2,300 years ago. This is the oldest crop found in eastern Africa. It dates to a time when local people also began to use domestic cattle.

They also found evidence that sorghum (an ancient grain) arrived in East Africa from the northeast about 1,000 years ago.

Another crop took the researchers by surprise. Mueller’s team uncovered a burnt, but perfectly intact field pea. Peas were not previously considered part of early agriculture in the region.

“To our knowledge, this is the only evidence of peas in Iron Age eastern Africa,” Mueller says.

“The standard peas that we eat in North America were domesticated in the near east,” Mueller says. “They were grown in Egypt and probably ended up in east Africa by travelling down the Nile through Sudan, which is also likely how sorghum ended up in east Africa. But there is another kind of pea that was domesticated independently in Ethiopia called the Abyssinian pea, and our sample could be either one.”

Emmanuel Ndiema is from the National Museums of Kenya, a project partner on the research.

“Our findings at Kakapel reveal the earliest evidence of domesticated crops in east Africa, reflecting the dynamic interactions between local herders and incoming Bantu-speaking farmers,” Ndiema says.

“Our work shows that African farming was constantly changing as people migrated, adopted new crops and abandoned others at a local level,” Mueller explains. “Prior to European colonialism, community-scale flexibility and decision-making was critical for food security – and it still is in many places.”

“This is where human evolution occurred. This is where hunting and gathering was invented by people,” Mueller says. “But there has been no archaeological evidence about which plants hunter-gatherers were eating from this region. If we can get that kind of information from this assemblage, then that is a great contribution.”