Résumé
Improving the yield of food crops is a central issue for upland development projects. In our review of the existing literature during the first phase of the study, we found that almost 50 percent of the references about evaluation of new technologies dealt with food crops. The respective shares of wetland and dryland in the total harvested area, however, differ substantially from one crop to another (figure 4.1).1 Lowland farming systems almost have a total monopoly on the supply of rice, with more than 90 percent of harvested area. Although soybean is considered an upland crop, more soybean is now harvested on wetland.2 Wetland production of soybean increased dramatically as a result of development programs implemented in the 1980s that encouraged lowland farmers to increase their soybean area. In contrast, most of the maize and groundnut crops are grown on drylands, while cassava is almost exclusively produced on dryland. (Résumé d'auteur)