Reduced tillage and green manures for sustainable organic cropping systems Organic farming systems contribute to ecosystem services such as the maintenance of soil quality and biodiversity. Reduced tillage and green manures are efficient conservation agriculture tools that can be adapted to further improve organic crop production systems. The TILMAN-ORG project’s overall goals are to design improved organic cropping systems with: (a) enhanced productivity and nutrient use efficiency, (b) more efficient weed management and (c) increased biodiversity, but (d) lower carbon footprints (in particular increased carbon sequestration and lower GHG emissions from soils). These goals will be achieved by adapting and integrating conservation agriculture techniques (in particular reduced tillage and improved use of green manures) into organic farming systems to intensify biological soil functions like nutrient cycling, soil carbon build-up, and biological nitrogen fixation, while at the same time optimising management protocols for weeds (which are the main challenge when introducing minimum tillage systems). Optimum techniques for organic systems will be identified using an integrated approach: i. Farmers’ experiences and perceptions about reduced tillage and green manures will be assessed in semi-structured interviews. Existing data from medium and long-term trials on reduced tillage and green manures provided by the consortium and the published existing peer reviewed and grey literature, will be evaluated with respect to yield stabilisation, soil quality and biodiversity (WP1 and WP2).ii. Experimental Case Studies on soil quality and greenhouse gas emissions, weed management and functional biodiversity, and improved nutrient management will be carried out, and carbon stocks under reduced tillage compared to ploughing will be measured (WPs3-5). Data from long-term tillage trials across Europe will be exploited to calibrate NDICEA, a decision support tool to predict soil organic carbon and nitrogen fluxes in the soil – plant system.iii. Design of optimised cropping systems by modelling approaches based on results from the literature and case studies (WP6). This will also involve the preparation of guidelines focused on helping farmers toaddress weed management challenges, and temporary shortages of nitrogen supply in order to improve yields and yield stability, thus improving both the environmental and economic sustainability of organic farming systems. The project’s dissemination activities will target farmers, advisors, and the scientific community, but also the agricultural support industries and policy makers. The main innovative strategy of the project is to adapt conservation agriculture approaches to organic farming drawing on existing field experiments across Europe.