I n the Boumango agroindustrial area (2°S, 13°E) of Gabon, 2000 ha has been intensively cropped since 1980 under mechanized conditions, with an annual sequence of maize and soybean. New alternative cropping systems are now required to solve the cultivation problems that have arisen. Experiments were carried out to test systems involving direct seeding on plant cover that were initially developed in central-western Brazil. Several soil fertility indicators were monitored over a 3-year period, their evolution under three different crop management sequences and two fertilizer levels are reported.