The production of industrial hemp (Cannabis sativa L.) has expanded recently in the US. Limited agronomic knowledge and supply chain issues, however, stemming from a long-standing cultivation ban, pose a barrier to continued market expansion of hemp, which leads to the import of most hemp products. This review examines the most recent cultivation methods, fertilizer and nutrient requirements, soil management practices, environmental parameters, and post-harvest processing methods, particularly in the context of environmental benefits such as soil phytoremediation and CO2 sequestration. Details of the valorization of hemp biomass into sustainable products, such as fibers, papers, packaging, textiles, biocomposites, biofuels, biochar, and bioplastics, along with current limitations and scope for improvements, are explored. Finally, an overall summary of the life cycle and techno-economic analysis aimed at optimizing their environmental performance and economic feasibility are discussed with a focus on inter with the growing circular economy paradigm.
Industrial hemp is a crop with a high tolerance and accumulation of lead (Pb). Improving the Pb tolerance and accumulation capacity of industrial hemp is of great scientific and practical importance. This study utilized a pot with soil contaminated with Pb to investigate the differences in Pb tolerance between two industrial hemp varieties, Yunma1 (YM) and Shaanxi Industrial Hemp (SM), under Pb stress. The results indicated that Pb mainly accumulates in the roots of YM and SM (70-80%), with YM having a higher Pb accumulation than SM. It is worth nothing that under high Pb concentration conditions (5000 mg/kg), the Pb accumulation capacity of YM is twice that of SM. Accumulation characteristics of Pb in different plant tissues followed the pattern: roots > stems > leaves > fibers > seeds. In YM, approximately 70% of the absorbed Pb was fixed in the roots and 30% was transported to the above-ground parts. In contrast, SM transported more than 50% of absorbed Pb by roots to the above-ground areas, causing some degree of damage to stems and leaves. Even when Pb concentrations exceed 4000 mg/kg, YM exhibits strong tolerance (tolerance index greater than 90%), with normal growth and no signs of toxicity. However, SM showed a tolerance level of < 50% at high Pb concentrations, with significant heavy metal toxicity symptoms in the above-ground areas. These results provide important information for the remediation of Pb contaminated soils in mining areas.