Bulletin No. ⁰²⁷ deals with two research themes. The spread of bean cultivation and the mapping of soil fertility in Burundi.

1. The first broadcast of The Bean would be started by the Vatican. It was introduced to Africa in the 20th century by the Portuguese. The bean also established itself well in East Africa, especially in the Great Lakes region (Kenya, Uganda, Tanzania) where it found ecological conditions similar to those of the Andean mountains. This region has also become a center of diversification and beans are still a staple food for rural populations. According to BAERT, the common bean was introduced to Burundi from Angola between the 17th and 18th centuries. Beans are classified among the first subsistence crops in this country. It is the most consumed food at any meal and provides 20% of calories and 50% of proteins and micronutrients.

Soil fertility mapping in Burundi was carried out to analyze the evolution of fertility in comparison with maps produced in 2013. These offer a decision-making tool for taking clear guidelines in terms of fertilizers and amendments by adapting their intake, in quality and quantity, according to the availability of nutrients and other soil parameters.
The maps thus produced will support the situation of the various Burundian soils such as: acidity, the content of total nitrogen, exchangeable calcium, organic carbon, exchangeable magnesium, assimilable phosphorus, exchangeable potassium, exchangeable potassium, the (Ca+Mg) /K ratio, the (Ca+Mg) /K ratio, the Ca/Mg ratio, the C/N ratio as well as the Mg/K ratio.