To overcome adoption barriers of EU agri-environmental schemes (AES) related to the organizational burden from complying with the schemes’ inflexible land management prescriptions, the EU has introduced result-based AES. Farms receive compensation once a contracted environmental result is verified. However, desired large-scale adoption of these result-based schemes is threatened since participating farmers risk losing the premium if they cannot reach the environmental target. This study aims at investigating acceptance of a hypothetically result-based AES for arable farmers in North-Rhine Westphalia, Germany, and elicit the role of behavioral factors and a social nudge for acceptance. The hypothetical scheme targets at increasing biodiversity of pollinator and bird species by supporting weed-species richness in intensive arable production. We used a split-treatment design to investigate the influence of a social nudge on scheme participation and area enrolled in the scheme (intensity). We rely on a convenience sample of 63 farmers and find an average willingness to participate of about 60%. Results indicate no influence of the social nudge on participation and intensity. Cognitive factors determine the willingness to participate while social and dispositional factors determine the intensity decision. This study sheds light on farmers’ decision-making and delivers a pilot-scheme for follow-up studies.