The objective of this new approach is to show the interest of experimenting in real farmers conditions with a participatory approach, improved rubber agroforestry systems (RAS) as alternatives to traditional "jungle rubber" practices or to classical rubber based development schemes based on estate technology. The main challenge for research is to test various kinds of improved planting materials and appropriate levels of inputs and labour to see which grow and produce best in such agroforestry systems, and which are most appropriate-and affordable-for smallholders (Barlow 1993, Penot 1994, 1995, 1996). A network of on-farm experiments has been developed with 100 farmers in 3 selected provinces (Penot, 1994, 1996 & 1997): Jambi and West-Sumatra in Sumatra and West-Kalimantan in Borneo. All innovations tested in this programme have been discussed with farmers in order to improve adoptability and suitability of RAS technologies according to farmers resources and requirements. Experimentation is based on how to minimize purchased inputs and labour while conserving agroforestry practices and its advantages: income diversification, income during rubber immature period through intercropping, maintenance of a certain level of biodiversity and environmental soundness. SRAP is using a participatory approach to do on-farm experimentation with three main kinds of rubber agroforestry systems (RAS) Each is being tested for its suitability for local agro-ecological conditions, for labour and cost requirements and to determine the best level of intensification.