References Chenu, C., Angers, D.A., Barré, P., Derrien, D., Arrouays, D., Balesdent, J., 2019. Increasing organic stocks in agricultural soils: Knowledge gaps and potential innovations. Soil and Tillage Research 188, 41-52. Elser, J., Bennett, E., 2011. Phosphorus cycle: a broken biogeochemical cycle. Nature 478, 29. Erisman, J.W., Sutton, M.A., Galloway, J., Klimont, Z., Winiwarter, W., 2008. How a century of ammonia synthesis changed the world. Nature Geoscience 1, 636. Hobley, E., Baldock, J., Hua, Q., Wilson, B., 2017. Land‐use contrasts reveal instability of subsoil organic carbon. Global change biology 23, 955-965. Hobley, E., Steffens, M., Bauke, S.L., Kögel-Knabner, I., 2018. Hotspots of soil organic carbon storage revealed by laboratory hyperspectral imaging. Scientific reports 8, 13900. Towards more efficient carbon, nitrogen and phosphorus cycling in European agricultural soils: Circular Agronomics (CA) program Yaser Ostovari1, Jan Willem Van Groenigen2, Rachel Creamer2, Julien Guigue1 ,Eleanor Hobley1, Laura Ferron2, Henk Martens2, Emily Overtuf1, Anke Neumeier1, Andreas Muskolus3, Paolo Mantovi4, Francesc Domingo Olivé5, Thomas Guggenberger6, Marek Holba7, Ingrid Kögel-Knabner1, Alix Vidal1 1TU München, Lehrstuhl für Bodenkunde, Freising, Germany, 2Wageningen University, Soil Biology Group, Wageningen, The Netherlands, 3Landwirtschaftliche Versuchsstation Berge, Berlin, Germany, 4Fondazione CRPA Studi Ricerche, Reggio Emilia, Italy, 5IRTA Mas Badia, Agricultural Experimental Station MasBadia, La Tallada d’Emporda, Spain, 6Höhere Bundeslehr- und Forschungsanstalt für Landwirtschaft Raumberg-Gumpenstein, Irdning, Austria, 7ASIO SPOL SRO, Brno, Czech Republic 1) CATALONIA, Spain (leader: IRTA) 2) BRANDENBURG, Germany (leader: IASP) 3) LUNGAU, Austria (leader: AREC) 4) EMILIA-ROMAGNA, Italy (leader: FCSR) 5) GELDERLAND, The Netherlands(leader: WUR) 6) SOUTH MORAVIA, Czech Republic (leader: ASIO) 1 2 3 4 5 6 Case Study Sites Material and methods Organic and inorganic amendments Different organic and inorganic amendments according to the case study. E.g., mineral fertilizer, pig slurry (solid or liquid fraction), manure, whey, biogas digestate, nitrogen-depleted digestate. Soil sampling for every case study Soil sampling to a depth of 1 m using a hydraulic corer. One un-disturbed half of the core for hyperspectral imaging The other half of the core for laboratory analyses. Five depths: 0-10 cm,10-20 cm, 20-40 cm, 40-80 cm and 80-100 cm. Laboratory analyses Classical bulk chemical analyses. E.g., bulk density, pH, CEC, texture, total and available C, N and P State-of the-art imaging technique: hyperspectral camera to reveal horspots of C and N storage in the soil profile (Hobley et al., 2018). A focus on hyperspectral soil analysis Introduction Mineral fertilizers: low recovery efficiency by crops. E.g., 30-50 % for nitrogen (N) and 45 % for phosphorus (P) (Tilman et al., 2002). Loss of nutrients into the environment : severe negative influence on soil (e.g. unbalanced N cycle), water (e.g., eutrophisation) and air (e.g., greenhouse gas emissions) (Elser and Bennett, 2011; Erisman et al., 2008). Less than 2% soil organic carbon (SOC) in 45% of European soils (Jones et al., 2012) and projected decline of agricultural SOC stocks of up to 24 % (Wiesmeier et al., 2016). Soil carbons stocks: not only topsoils, but also subsoils are reactive to agricultural change (Hobley et al., 2017). Impacts of organic amendments (e.g., digestate, manure) versus traditional mineral fertilizers on SOC contents and stocks are uncertain at the long-term (e.g., Chenu et al., 2019). Within the project Circular Agronomics - production of new organic fertilizers: residues (manure, digestate) treated with vacuum degasification for nitrogen depletion of residues and recovery of fertilizer. One of the objectives of Circular Agronomics Exploring medium and long-term effect of new organic fertilizers versus classical organic and mineral f