High-protein legume grain import dependency has placed Scottish organic producers in an unattractive position financially, and environmentally. High import prices and price-volatility can be avoided by producing legume grains ‘at home’. This approach also offers environmental benefits, as legume crop residues present a complex organic provision to help realise more holistic crop rotations. The potential is due to ‘biological nitrogen fixation’, a process whereby atmospheric nitrogen is ‘fixed’ into biologically useful forms. This is a function of the symbiosis between legumes and soil bacteria termed ‘rhizobia’. The benefits of high protein grain production are therefore allied to enriching crop residues which remain in-field. Here, protein yield, yield qualities, and soil-enrichment potential will be maximised using novel grain legume and cereal ‘crop mixtures’, i.e., cultivating multiple crop species in the same field at the same time. The project also tests the efficacy of elite-rhizobia to further optimise the protein yield potential