Transforming industrial by-products into new resources is a fundamental principle of sustainable agriculture and circular bioeconomy. Waste products from rosemary (Rosmarinus officinalis L.) essential oil extraction, such as exhausted biomass and water residues (WRs), are rich in bioactive compounds like phenols and terpenes. These by-products may represent a promising and economically viable option for agricultural management, particularly in weed control. This study evaluates the potential use of WR as a bioherbicide. In vitro experiments were conducted to assess the inhibitory effects of WR on the germination and seedling morphology (root and shoot development) of four detrimental weed species for temperate cropping systems: two monocotyledonous (Alopecurus myosuroides and Lolium multiflorum) and two dicotyledonous (Sinapis alba and Amaranthus retroflexus). WR was tested at four concentrations (0, 25, 50, and 100), corresponding to an increasing gradient of WR, with 100 representing pure WR. The results showed that WR did not significantly inhibit germination in A. myosuroides, L. multiflorum and S. alba, whereas A. retroflexus exhibited a dose-dependent inhibition, with germination reduced by 37.5%, 64.5%, and 91.6% at doses of 25, 50, and 100, respectively, compared with the control (dose 0). Furthermore, germination delays were observed across all tested species with promising application of WR for regulating weed–crop competitive interactions in the early crop growth stages. Results on the morphological traits of weed seedlings showed that WR application affected root more than shoot growth inhibition. In particular, WR demonstrated a pronounced root inhibitory effect in A. myosuroides, L. multiflorum, and A. retroflexus. In contrast, a dose-dependent increase in root length was observed for S. alba (21.41 mm at dose 0 and 25.77 mm, 30.97 mm and 35.96 mm, respectively, at doses 25, 50, and 100). The results of this study highlight the potential application of WR as a sustainable solution to be included in an integrated weed management (IWM) toolbox and underscore their role in promoting the valorization of waste from essential oil production.

Agroforestry systems (AFSs) enhance long-term carbon sequestration through tree biomass accumulation. As the European Union’s Carbon Farming Certification (CRCF) Regulation now recognizes AFSs in carbon farming (CF) schemes, accurate tree biomass estimation becomes essential for certification. This review examines field-destructive and remote sensing methods for estimating tree aboveground biomass (AGB) in AFSs, with a specific focus on their advantages, limitations, timing, and associated costs. Destructive methods, although accurate and necessary for developing and validating allometric equations, are time-consuming, costly, and labour-intensive. Conversely, satellite- and drone-based remote sensing offer scalable and non-invasive alternatives, increasingly supported by advances in machine learning and high-resolution imagery. Using data from the INNO4CFIs project, which conducted parallel destructive and remote measurements in an AFS in Tuscany (Italy), this study provides a novel quantitative comparison of the resources each method requires. The findings highlight that while destructive measurements remain indispensable for model calibration and new species assessment, their feasibility is limited by practical constraints. Meanwhile, remote sensing approaches, despite some accuracy challenges in heterogeneous AFSs, offer a promising path forward for cost-effective, repeatable biomass monitoring but in turn require reliable field data. The integration of both approaches might represent a valid strategy to optimize precision and resource efficiency in carbon farming applications.