Petra Rietberg (MSc) conducted this study as research fellow at the Plant Production Systems group of Wageningen University, investigating oil palm smallholders’ sustainability in relation to intensification and certification. During her master studies in environmental policy and soil science at Wageningen University, she conducted field work in Indonesia and Uruguay. As a researcher at the Louis Bolk Institute, she contributed to on-farm research and facilitated knowledge exchange between farmers and researchers on soil management and sustainable cropping systems. She has a keen interest in how farmers and other producers deal with natural resources and why they do so, and in combining participatory methods, modelling and on-farm research to explore options to make farming systems more sustainable.