Local soil knowledge is an important source of information when designing sustainable agricultural strategies. This knowledge participates essentially in farmer adoption process of new agricultural techniques proposed by research. Besides, several ethnopedological studies has recognized the effectiveness of local knowledge and that its carelessness contributed widely to the failures of numerous development projects. However, little effort has been made to study soil local knowledge in Madagascar, an essentially agricultural country. This project aims to take into account local knowledge as a tool for sustainable agricultural systems. The objectives are to (i) study local soil knowledge to compare with French and FAO soil classification, (ii) identify local soil fertility indicators and compare them with those used by scientists, (iii) analyse farmer practice of soil fertility in order to produce knowledge and new practice processes that are suitable for farmers and valid for scientists.To achieve these objectives, semi-directive surveys will be carried out among 400 farmers. Soil samples for chemical analyses will supplement the methodology.The results would improve communication and interactivity between farmers, scientists and extension workers to build up an active knowledge, consensus agricultural practices that are adaptable for a sustainable agriculture in Madagascar.