Fonio is a little-known grain in the Western world. The book “Lost Crops of Africa” has an entire chapter devoted to Fonio, also called “Acha”. It is a survival grain for many people in Africa because it reaches maturity sooner than any of the major cereals (wheat, rice, corn, barley, etc.). A fonio crop can go from planting to harvest in 6 to 8 weeks. Most grains require 3 to 5 months (12 to 20 weeks) to reach maturity.
Sometimes fonio is grown, in Africa, as an emergency crop. If the main crop of rice, wheat, or corn fails midway through the crop season, they plant fonio, and it comes to harvest about the same time that the failed crop would have been ready. So instead of starvation, due to crop failure, they have a nutritious grain.
Fonio is adapted to grow with minimal rainfall. By comparison corn and rice are rather thirsty crops. Fonio is drought and heat resistant, but it prefers hot dry weather over cool damp conditions. It thrives without irrigation and with minimal inputs (fertilizer, weeding etc.). Fonio can be successfully grown on land where wheat, rice, corn, and barley would all fail.
The main disadvantage to fonio is the small grain size. This makes the crop more difficult to thresh and winnow. Hulling fonio is difficult, for this reason. But the whole grains can be milled for flour, without dehulling.
Fonio is nutritious. It is about 9% protein by weight, so it is higher in protein than rice. The protein has all essential amino acid in good proportions except lysine. It is a good sources of fiber, phosphorus, and carbohydrates.
For prepping and survival purposes, it would be good to have some fonio seeds as part of your stored gardening seeds. Experiment with the crop, to see how it fares on your soil. The short time from planting to harvest is its main advantage over other crops.