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 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.