Soils developed on voIcanic parent materials have many intrinsic qualities favourable to cropping. Howerer, fertility decreases dramatically when they are badly managed. A short review and case studies from Reunion and Guadeloupe highight the special characteristics of these soils, and their response to management. The interplay of cropping systems and physical characteristics of Andisols is first considered through the example of Pelargonium and food crop systems in Reunion. Progressive decrease in production and cropping potential shows in falling yields as well as in the overall decline of the system. The example of banana production in Guadeloupe highights the increase in inputs needed to realise the land's potential and to maintain yields, in particular more tillage and pest treatment. In both cases, these trends are connected to the co-evolution of soil characteristics and cropping systems. They lead to an increase of risks with less security and less scope in the choice of cropping systems. Technical solutions in the form of erosion-control measures, rotation and planting techniques have been developed and prove to be relevant and consistent in their benefit.