Valorization of agro-industrial residues and sheep manure through composting and agronomic application on beet (Beta vulgaris L.) in Arenosol

Abstract The valorization of organic waste by composting reflects a sustainable substitute for the management of agro-industrial residues in Morocco, particularly in the Gharb region. This study investigates the production of compost from residues originating from two industrial units: essential oil hydrodistillation and red fruit processing, combined with sheep manure incorporated at the beginning of the composting process. The process was evaluated over 90 days using an integrated approach combining physicochemical analyses. Temperature monitoring revealed a robust thermophilic phase, with temperatures reaching 65°C, ensuring effective hygienization of the compost. The final compost exhibited physicochemical properties favorable for agronomic use, including a stable C/N ratio of 16.63, a near-neutral pH (7.30), and a non-limiting electrical conductivity (3.64 mS/cm). Agronomic evaluation was carried out on beetroot ( Beta vulgaris L.) cultivated in experimental plots at the Faculty of Sciences of Kenitra, on a soil classified as an Arenosol according to the World Reference Base (WRB) classification. The compost was applied at a rate of 25% (v/v), previously identified as optimal, and compared with a non-amended control soil. The results revealed a significant increase in tuberous root weight and leaf number in the compost-amended treatment, confirming the agronomic potential of the compost and its beneficial effect on the fertility of Arenosols.