My current research focus is on developing and improving of agro-ecosystem models with low external input for sustainable agriculture (field trials and greenhouse experiments). I work in various environments and cropping systems, from perennial tropical systems (coffee, clove, cacao, kayu putih, etc) and small-scale farming in Indonesia (rice, maize, legumes, etc). Main topics are agronomy, agroforestry, yield gap analysis, crop simulation, soil fertility and marginal lands (coastal sandy, rainfed areas, karst areas, etc)