What I didn't know (since I worked in urban Liberia, not in a rural area) was that rice was independently domesticated in West Africa around 1500 BC from a wild plant that grew there.
From Kew garden site:
Oryza glaberrima Steud.
Widespread in cultivation.
African rice grows best on fertile alluvial soils although it tolerates low soil fertility and can produce higher yields than Asian rice on alkaline and phosphorus-deficient soils. Floating rice is planted on loam or clay soils.
There are only two species of cultivated rice in the world: Asian rice (Oryza sativa) and African rice (Oryza glaberrima). African rice is native to West Africa, where it is cultivated as a foodcrop. It is known for its hardiness and its ability to compete with weeds, pests, infertile soils and human neglect. However, increasingly African rice is being replaced by the introduced Asian varieties of Oryza sativa, which produce a higher yield than African rice, shatter less easily and have a softer grain that is easier to mill.
This article notes that a new cross breed of both rices has greater yields and could help the growing population in West Africa.