This project uses an experimental design to evaluate the longer-term impact of organic farming training in Indonesia, a country that struggles with land degradation and overuse of agricultural inputs but where policy makers and non-governmental organizations have also expressed strong interest to promote organic farming. The research team can build upon a previous research project that investigated the short-term impact of organic farming training. The project included a randomized controlled trial in which 1,200 smallholders in Indonesia were interviewed in 2018 and 2019 and 600 of these smallholders were invited to an organic farming training (a third wave of data collection will take place late 2021). In the new project, we will add a second training intervention to deepen farmers’ knowledge about organic farming practices. The training will be complemented by soil testing. A fourth wave of data collection will be implemented in this project in 2023, thereby creating unique panel data on sustainable farming.