Agronomic performance, carbon storage and nitrogen utilisation of long-term organic and conventional stockless arable systems in Mediterranean area

•We assessed sixteen years of agronomic performance and environmental sustainability.•Organic agroecosystems produced comparable crop grain yields respect to the conventional.•Conventional agroecosystem showed a larger N surplus and a lower crop N use efficiency.•Organic agroecosystems were more effective in terms of soil C and soil N storage.•Organic farming in Mediterranean increase environmental sustainability.