Precision farming systems promise a highly efficient resource use reducing cost for farmers and contributing to the preservation of the environment. A major obstacle, however, in such systems dissemination is the reluctant adoption by farmers. Prior work is suggesting that mainly knowledge or missing resources for investment are barriers, while social norms are rarely addressed for precision farming systems. We adopt the reasoned action approach including behavioural, social, and control aspects to analyse intentions and actual use of sustainable digital fertilisation methods. Based on a German sample of farmers, we find that social norm is the major predictor, while behavioural and control aspects surprisingly are not relevant at all. The results contribute to the understanding of what drives farmers in adopting precision farming systems on a theoretical basis and highlight the importance of considering social norms in increasing adoption.