Chemical Characterization and Resource Utilization Potential of By-Products from Hydroponic Strawberry Cultivation

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.