Strawberry cultivation generates substantial amounts of agricultural by-products, including spent substrates and plant residues, particularly in hydroponic production systems. However, information on the occurrence and management of these by-products remains limited. This study investigated the generation, disposal practices, and chemical characteristics of by-products from hydroponic strawberry cultivation in two major strawberry-producing regions of Republic of Korea, Nonsan and Jinju. Based on national statistics and field surveys, annual by-product generation was estimated at 605,400 m³ of spent substrates and approximately 25,729 t fresh weight and 6003 t dry weight of plant residues. Disposal practices varied regionally: in Jinju, over 80% of by-products were recycled as compost or feed, whereas in Nonsan, recycling rates were lower and a considerable portion remained untreated or were improperly disposed of. Analyses of 463 pesticides and seven heavy metals (Zn, Cu, Ni, Pb, As, Cd, and Hg) confirmed concentrations below the permissible limits, supporting their chemical suitability for potential recycling use. Inorganic analyses revealed high levels of N, Ca, P, and K, suggesting their potential as alternative nutrient sources and as raw materials for recycled fertilizer or soil amendment. Because strawberry by-products are generated continuously throughout the cultivation cycle, their management requires decentralized and long-term strategies. These results provide the first comprehensive assessment of the generation scale, disposal practices, and chemical characteristics of strawberry by-products in Republic of Korea, suggesting their potential as alternative nutrient resources or raw materials for recycled fertilizer or soil amendment under appropriate pretreatment and management.

Considering carbon neutrality and fossil fuel depletion, biomass is becoming increasingly important as a renewable and sustainable energy source. However, understanding of process-dependent characteristics relevant to char production remains limited. This study investigated the carbonization of mushroom waste medium (MWM) via conventional carbonization (CC; i.e., pyrolysis), hydrothermal carbonization (HTC), and microwave-assisted carbonization (MAC), and evaluated their suitability for desired char properties and target applications. For all methods, increasing reaction temperature led to carbon densification, with decreased oxygen and hydrogen contents and increased carbon and fixed carbon fractions. However, the extent of these transformations depended on the reaction environment. HTC achieved carbon enrichment and the highest higher heating value (HHV) at relatively low temperatures. In contrast, CC required higher temperatures to achieve comparable carbonization levels but showed a marked increase in BET surface area at higher temperatures. MAC exhibited intermediate characteristics under moderate conditions. HTC also facilitated potassium and chlorine removal, which may reduce operational issues during thermal utilization. These results indicate trade-offs among carbon densification, char yield, surface structure, and inorganic matter content. Rather than identifying a universally superior process, this study demonstrates that the suitability of each method depends on the desired properties and applications of MWM-derived char, providing a practical basis for appropriate process selection.

Strawberry cultivation generates substantial amounts of agricultural by-products, including spent substrates and plant residues, particularly in hydroponic production systems. However, information on the generation scale, disposal practices, and resource utilization potential of these by-products remains limited. This study investigated the generation scale, disposal practices, and chemical characteristics of by-products from hydroponic strawberry cultivation in two major strawberry-producing regions of Korea, Nonsan in Chungcheongnam-do and Jinju in Gyeongsangnam-do. Based on national statistics and field surveys, annual by-product generation was estimated at 605,400 kL of spent substrates and approximately 25,729 t fresh weight and 6,003 t dry weight of plant residues. Disposal practices varied regionally: in Jinju, over 80% of by-products were recycled as compost or feed, whereas in Nonsan, recycling rates were lower and much was untreated or dumped. Analyses of 463 pesticides and seven heavy metals (Zn, Cu, Ni, Pb, As, Cd, Hg) confirmed concentrations below permissible limits, ensuring safety for recycling. Inorganic analyses showed high levels of N, Ca, P, and K, suggesting potential use as alternative fertilizers. Unlike other greenhouse crops that generate residues mainly at harvest, strawberries produce by-products continuously, requiring decentralized and long-term management. These findings highlight the potential of strawberry by-products for resource utilization and their contribution to environmental conservation and sustainable agriculture when supported by pretreatment, monitoring, and integrated management. These results provide the first comprehensive assessment of the generation scale, disposal practices, and chemical safety of strawberry by-products in Korea, demonstrating their potential as alternative nutrient resources for circular agriculture.